UTKInput Validation 기능 추가

2026-02-12 18:04:38 +09:00
parent df6d3e3b5a
commit 93e1423525
54 changed files with 2900 additions and 188 deletions
--- a/Assets/Resources/UIToolkit/Button/UTKCheckBox.uss
+++ b/Assets/Resources/UIToolkit/Button/UTKCheckBox.uss
@@ -55,7 +55,7 @@
    width: 14px;
    height: 14px;
    font-size: 12px;
-    color: var(--color-base-01);
+    color: var(--color-text-primary);
    -unity-text-align: middle-center;
    -unity-font-style: bold;
    opacity: 0;
--- a/Assets/Resources/UIToolkit/Button/UTKToggle.uss
+++ b/Assets/Resources/UIToolkit/Button/UTKToggle.uss
@@ -50,6 +50,7 @@
 .utk-toggle > .unity-toggle__input > .unity-toggle__checkmark {
    width: 14px;
    height: 14px;
+    border-width: 0;
    border-radius: var(--radius-full);
    background-color: var(--color-text-secondary);
    -unity-background-image-tint-color: transparent;
--- a/Assets/Resources/UIToolkit/Input/UTKBoundsField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKBoundsField.uss
@@ -12,6 +12,8 @@
 .utk-boundsfield {
    flex-direction: row;
    align-items: flex-start;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -101,6 +103,35 @@
   Disabled State
   =================================== */

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-boundsfield--error .unity-float-field > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-boundsfield--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-boundsfield__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
+/* ===================================
+   Disabled State
+   =================================== */
+
+.utk-boundsfield--disabled {
+    cursor: arrow;
+}
+
 .utk-boundsfield--disabled > .unity-label {
    color: var(--color-text-disabled);
 }
@@ -108,4 +139,9 @@
 .utk-boundsfield--disabled .unity-float-field > .unity-base-text-field__input {
    background-color: var(--color-btn-disabled);
    color: var(--color-text-disabled);
+    cursor: arrow;
+}
+
+.utk-boundsfield--disabled .unity-float-field > .unity-base-text-field__input:focus {
+    border-color: var(--color-border);
 }
--- a/Assets/Resources/UIToolkit/Input/UTKDoubleField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKDoubleField.uss
@@ -12,6 +12,8 @@
 .utk-double-field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -55,6 +57,28 @@
    border-color: var(--color-border-focus);
 }

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-double-field--error > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-double-field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-double-field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    padding-left: 68px;
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
 /* ===================================
   Disabled State
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKFloatField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKFloatField.uss
@@ -12,6 +12,8 @@
 .utk-float-field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -55,6 +57,28 @@
    border-color: var(--color-border-focus);
 }

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-float-field--error > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-float-field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-float-field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    padding-left: 68px;
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
 /* ===================================
   Disabled State
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKFloatStepper.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKFloatStepper.uss
@@ -12,7 +12,9 @@
 .utk-number-stepper {
    flex-direction: row;
    align-items: stretch;
-    height: var(--size-input-height);
+    flex-wrap: wrap;
+    height: auto;
+    min-height: var(--size-input-height);
 }


@@ -154,3 +156,29 @@
 .utk-number-stepper--disabled .utk-number-stepper__btn:active {
    background-color: var(--color-btn-disabled);
 }
+
+
+/* ===================================
+   Error State
+   =================================== */
+
+.utk-number-stepper--error .utk-number-stepper__text-input {
+    border-top-color: var(--color-border-error);
+    border-bottom-color: var(--color-border-error);
+    border-left-color: var(--color-border-error);
+}
+
+.utk-number-stepper--error .utk-number-stepper__btn {
+    border-top-color: var(--color-border-error);
+    border-right-color: var(--color-border-error);
+    border-bottom-color: var(--color-border-error);
+}
+
+/* Error Message Label */
+.utk-number-stepper__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
--- a/Assets/Resources/UIToolkit/Input/UTKInputField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKInputField.uss
@@ -12,6 +12,8 @@
 .utk-input {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -99,6 +101,16 @@
    color: var(--color-state-error);
 }

+/* Error Message Label */
+.utk-input__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    padding-left: 68px;
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
 /* ===================================
   Variants
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKIntStepper.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKIntStepper.uss
@@ -12,7 +12,9 @@
 .utk-number-stepper {
    flex-direction: row;
    align-items: stretch;
-    height: var(--size-input-height);
+    flex-wrap: wrap;
+    height: auto;
+    min-height: var(--size-input-height);
 }


@@ -154,3 +156,28 @@
 .utk-number-stepper--disabled .utk-number-stepper__btn:active {
    background-color: var(--color-btn-disabled);
 }
+
+/* ===================================
+   Error State
+   =================================== */
+
+.utk-number-stepper--error .utk-number-stepper__text-input {
+    border-top-color: var(--color-border-error);
+    border-bottom-color: var(--color-border-error);
+    border-left-color: var(--color-border-error);
+}
+
+.utk-number-stepper--error .utk-number-stepper__btn {
+    border-top-color: var(--color-border-error);
+    border-right-color: var(--color-border-error);
+    border-bottom-color: var(--color-border-error);
+}
+
+/* Error Message Label */
+.utk-number-stepper__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
--- a/Assets/Resources/UIToolkit/Input/UTKIntegerField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKIntegerField.uss
@@ -12,6 +12,8 @@
 .utk-integer-field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -55,6 +57,28 @@
    border-color: var(--color-border-focus);
 }

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-integer-field--error > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-integer-field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-integer-field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    padding-left: 68px;
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
 /* ===================================
   Disabled State
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKLongField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKLongField.uss
@@ -12,6 +12,8 @@
 .utk-long-field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -55,6 +57,27 @@
    border-color: var(--color-border-focus);
 }

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-long-field--error > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-long-field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-long-field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    padding-left: 68px;
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+}
+
 /* ===================================
   Disabled State
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKRectField.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKRectField.uss
@@ -12,6 +12,8 @@
 .utk-rectfield {
    flex-direction: row;
    align-items: flex-start;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -92,6 +94,35 @@
   Disabled State
   =================================== */

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-rectfield--error .unity-float-field > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-rectfield--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-rectfield__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
+/* ===================================
+   Disabled State
+   =================================== */
+
+.utk-rectfield--disabled {
+    cursor: arrow;
+}
+
 .utk-rectfield--disabled > .unity-label {
    color: var(--color-text-disabled);
 }
@@ -99,4 +130,9 @@
 .utk-rectfield--disabled .unity-float-field > .unity-base-text-field__input {
    background-color: var(--color-btn-disabled);
    color: var(--color-text-disabled);
+    cursor: arrow;
+}
+
+.utk-rectfield--disabled .unity-float-field > .unity-base-text-field__input:focus {
+    border-color: var(--color-border);
 }
--- a/Assets/Resources/UIToolkit/Input/UTKVector2Field.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKVector2Field.uss
@@ -12,6 +12,8 @@
 .utk-vector2-field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
    margin-right: 0;
 }

@@ -98,6 +100,27 @@
    border-color: var(--color-border-focus);
 }

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-vector2-field--error .unity-float-field > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-vector2-field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-vector2-field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
 /* ===================================
   Disabled State
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKVector3Field.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKVector3Field.uss
@@ -12,6 +12,8 @@
 .utk-vector3-field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
    margin-right: 0;
 }

@@ -93,6 +95,27 @@
    border-color: var(--color-border-focus);
 }

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-vector3-field--error .unity-float-field > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-vector3-field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-vector3-field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
 /* ===================================
   Disabled State
   =================================== */
--- a/Assets/Resources/UIToolkit/Input/UTKVector4Field.uss
+++ b/Assets/Resources/UIToolkit/Input/UTKVector4Field.uss
@@ -12,6 +12,8 @@
 .utk-vector4field {
    flex-direction: row;
    align-items: center;
+    flex-wrap: wrap;
+    height: auto;
 }

 /* ===================================
@@ -79,6 +81,35 @@
   Disabled State
   =================================== */

+/* ===================================
+   Error State
+   =================================== */
+
+.utk-vector4field--error .unity-float-field > .unity-base-text-field__input {
+    border-color: var(--color-border-error);
+}
+
+.utk-vector4field--error > .unity-label {
+    color: var(--color-state-error);
+}
+
+/* Error Message Label */
+.utk-vector4field__error-message {
+    width: 100%;
+    margin-top: var(--space-xs);
+    font-size: var(--font-size-caption);
+    color: var(--color-state-error);
+    white-space: normal;
+}
+
+/* ===================================
+   Disabled State
+   =================================== */
+
+.utk-vector4field--disabled {
+    cursor: arrow;
+}
+
 .utk-vector4field--disabled > .unity-label {
    color: var(--color-text-disabled);
 }
@@ -86,4 +117,9 @@
 .utk-vector4field--disabled .unity-float-field > .unity-base-text-field__input {
    background-color: var(--color-btn-disabled);
    color: var(--color-text-disabled);
+    cursor: arrow;
+}
+
+.utk-vector4field--disabled .unity-float-field > .unity-base-text-field__input:focus {
+    border-color: var(--color-border);
 }
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKBoundsFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKBoundsFieldSample.uxml
@@ -14,6 +14,22 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Positive Extents -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Positive Extents)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKBoundsField name="bounds-validation" label="Collider" class="utk-sample-bounds-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="bounds-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKDoubleFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKDoubleFieldSample.uxml
@@ -22,6 +22,30 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Range -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Range: 0.0 ~ 100.0)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKDoubleField name="double-validation-range" label="Percent" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validation - Positive -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Positive Only)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKDoubleField name="double-validation-positive" label="Distance" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="double-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKFloatFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKFloatFieldSample.uxml
@@ -22,6 +22,30 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Range -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Range: 0 ~ 100)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKFloatField name="float-validation-range" label="Speed" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validation - Positive -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Positive Only)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKFloatField name="float-validation-positive" label="Weight" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="float-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uss
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uss
@@ -0,0 +1,10 @@
+/*
+ * ===================================
+ * UTKFloatStepperSample.uss
+ * Float Stepper Sample Specific Styles
+ * ===================================
+ */
+
+.utk-sample-stepper {
+    width: 150px;
+}
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uss.meta
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uss.meta
@@ -0,0 +1,11 @@
+fileFormatVersion: 2
+guid: f2dcdd47a630b394ea19ea8b91f61d01
+ScriptedImporter:
+  internalIDToNameTable: []
+  externalObjects: {}
+  serializedVersion: 2
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
+  script: {fileID: 12385, guid: 0000000000000000e000000000000000, type: 0}
+  disableValidation: 0
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uxml
@@ -0,0 +1,63 @@
+<?xml version="1.0" encoding="utf-8"?>
+<UXML xmlns="UnityEngine.UIElements" xmlns:utk="UVC.UIToolkit">
+    <Style src="../UTKSampleCommon.uss" />
+    <Style src="UTKFloatStepperSample.uss" />
+
+    <VisualElement class="utk-sample-container">
+        <Label class="utk-sample-desc" text="실수 스테퍼 컴포넌트 (증감 버튼 포함)" />
+
+        <!-- Step 0.1 -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Step 0.1" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKFloatStepper name="stepper-step01" min-value="0" max-value="10" value="5.5" step="0.1" class="utk-sample-stepper" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Step 0.5 -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Step 0.5" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKFloatStepper name="stepper-step05" min-value="0" max-value="10" value="2.5" step="0.5" class="utk-sample-stepper" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Wrap Around -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Wrap Around" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKFloatStepper name="stepper-wrap" min-value="0" max-value="1" value="0.5" step="0.1" wrap-around="true" class="utk-sample-stepper" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Disabled -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Disabled" />
+            <VisualElement class="utk-sample-row" name="float-stepper-disabled-row">
+                <!-- Disabled stepper will be created via C# to call SetEnabled(false) -->
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validation - Non-Zero -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Non-Zero)" />
+            <VisualElement class="utk-sample-row" name="float-stepper-validation-row">
+                <!-- Validation stepper will be created via C# -->
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="float-stepper-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Code Sample -->
+        <VisualElement class="utk-code-sample-container">
+            <utk:UTKCodeBlock name="code-csharp" title="C#" />
+            <utk:UTKCodeBlock name="code-uxml" title="UXML" />
+        </VisualElement>
+    </VisualElement>
+</UXML>
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uxml.meta
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKFloatStepperSample.uxml.meta
@@ -0,0 +1,10 @@
+fileFormatVersion: 2
+guid: 908e94035af6fc5419bdf2246bc903fd
+ScriptedImporter:
+  internalIDToNameTable: []
+  externalObjects: {}
+  serializedVersion: 2
+  userData: 
+  assetBundleName: 
+  assetBundleVariant: 
+  script: {fileID: 13804, guid: 0000000000000000e000000000000000, type: 0}
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKInputFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKInputFieldSample.uxml
@@ -38,6 +38,30 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Email -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Email)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKInputField name="input-validation-email" label="Email" placeholder="example@email.com" class="utk-sample-input-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validation - Required -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Required)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKInputField name="input-validation-required" label="Name" placeholder="이름을 입력하세요" class="utk-sample-input-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKIntStepperSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKIntStepperSample.uxml
@@ -38,6 +38,22 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Even Number -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Even Number Only)" />
+            <VisualElement class="utk-sample-row" name="stepper-validation-row">
+                <!-- Validation stepper will be created via C# -->
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="stepper-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKIntegerFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKIntegerFieldSample.uxml
@@ -22,6 +22,30 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Range -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Range: 1~150)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKIntegerField name="int-validation-range" label="Age" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validation - Positive -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Positive Only)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKIntegerField name="int-validation-positive" label="Quantity" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="int-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKLongFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKLongFieldSample.uxml
@@ -22,6 +22,30 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Range -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Range: 0 ~ 1,000,000)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKLongField name="long-validation-range" label="File Size" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validation - Positive -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Positive Only)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKLongField name="long-validation-positive" label="Count" value="0" class="utk-sample-input-field--narrow" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="long-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKRectFieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKRectFieldSample.uxml
@@ -14,6 +14,22 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Positive Size -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Positive Size)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKRectField name="rect-validation" label="Viewport" class="utk-sample-rect-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="rect-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKVector2FieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKVector2FieldSample.uxml
@@ -14,6 +14,22 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Non-Zero -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Non-Zero)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKVector2Field name="vec2-validation" label="Direction" class="utk-sample-vector2-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="vec2-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKVector3FieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKVector3FieldSample.uxml
@@ -14,6 +14,22 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Non-Zero -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (Non-Zero)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKVector3Field name="vec3-validation" label="Scale" class="utk-sample-vector3-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="vec3-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Sample/Input/UTKVector4FieldSample.uxml
+++ b/Assets/Resources/UIToolkit/Sample/Input/UTKVector4FieldSample.uxml
@@ -14,6 +14,22 @@
            </VisualElement>
        </VisualElement>

+        <!-- Validation - Normalized Color -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validation (0~1 Range)" />
+            <VisualElement class="utk-sample-row">
+                <utk:UTKVector4Field name="vec4-validation" label="RGBA" class="utk-sample-vector4-field" />
+            </VisualElement>
+        </VisualElement>
+
+        <!-- Validate All Button -->
+        <VisualElement class="utk-sample-section">
+            <Label class="utk-sample-section__title" text="Validate All (강제 검증)" />
+            <VisualElement class="utk-sample-row" name="vec4-validation-button-row">
+                <!-- Button created via C# -->
+            </VisualElement>
+        </VisualElement>
+
        <!-- Code Sample -->
        <VisualElement class="utk-code-sample-container">
            <utk:UTKCodeBlock name="code-csharp" title="C#" />
--- a/Assets/Resources/UIToolkit/Style/UTKDefaultStyle.uss
+++ b/Assets/Resources/UIToolkit/Style/UTKDefaultStyle.uss
@@ -258,7 +258,8 @@ Textfield 항목 스타일

 .unity-base-text-field {
    border-radius: 4px;
-    height: 24px;
+    /* height: 24px; */
+    height: auto;
    width: auto;
    margin-top: 0;
    margin-bottom: 0;
--- a/Assets/Resources/UIToolkit/Style/UTKThemeDark.uss
+++ b/Assets/Resources/UIToolkit/Style/UTKThemeDark.uss
@@ -50,20 +50,13 @@
    --color-blue-10: #062F4A;
    --color-blue-11: #001F33;

-    /* ===================================
-       Accent Colors - Blue Light (color-blue-light-*)
-       라이트 테마 선택 항목용 밝은 파란색
-       =================================== */
-    --color-blue-light-01: #B3D7FF;
-    --color-blue-light-02: #8EC5FF;
-
    /* ===================================
       Accent Colors - Red (color-red-*)
       =================================== */
    --color-red-01: #F14C4C;
    --color-red-02: #C74E39;
    --color-red-03: #FF0000;
-    --color-red-04: #264F78;
+    --color-red-04: #782626;

    /* ===================================
       Accent Colors - Green (color-green-*)
@@ -170,10 +163,10 @@
       =================================== */
    --color-calendar-sunday: var(--color-red-01);
    --color-calendar-saturday: var(--color-blue-02);
-    --color-calendar-today: var(--color-seti-orange);
+    --color-calendar-today: var(--color-green-02);
    --color-calendar-selected: var(--color-blue-06);
-    --color-calendar-range: rgba(66, 133, 244, 0.25);
-    --color-calendar-range-hover: rgba(66, 133, 244, 0.35);
+    --color-calendar-range: var(--color-blue-06);
+    --color-calendar-range-hover: var(--color-blue-07);

    /* ===================================
       Semantic Colors - State (color-state-*)
--- a/Assets/Resources/UIToolkit/Style/UTKThemeLight.uss
+++ b/Assets/Resources/UIToolkit/Style/UTKThemeLight.uss
@@ -41,67 +41,64 @@

    /* ===================================
       Accent Colors - Blue (color-blue-*)
-       라이트 테마에서는 약간 더 어두운 톤 사용
+       라이트 테마에서는 검정 텍스트가 잘 보이도록 밝은 톤 사용
       =================================== */
-    --color-blue-01: #0066CC;
-    --color-blue-02: #0078D4;
-    --color-blue-03: #106EBE;
-    --color-blue-04: #005A9E;
-    --color-blue-05: #004578;
-    --color-blue-06: #003F6E;
-    --color-blue-07: #003462;
-    --color-blue-08: #002952;
-    --color-blue-09: #001F3F;
-    --color-blue-10: #001530;
-    --color-blue-11: #000B1A;
-
-    /* ===================================
-       Accent Colors - Blue Light (color-blue-light-*)
-       라이트 테마 선택 항목용 밝은 파란색
-       =================================== */
-    --color-blue-light-01: #B3D7FF;
-    --color-blue-light-02: #8EC5FF;
+    --color-blue-01: #DCEEFB;
+    --color-blue-02: #B3D7F5;
+    --color-blue-03: #8AC0EF;
+    --color-blue-04: #62A8E8;
+    --color-blue-05: #3A90E0;
+    --color-blue-06: #2979C9;
+    --color-blue-07: #1A66B3;
+    --color-blue-08: #0D539C;
+    --color-blue-09: #044185;
+    --color-blue-10: #00306E;
+    --color-blue-11: #002057;

    /* ===================================
       Accent Colors - Red (color-red-*)
       =================================== */
-    --color-red-01: #D32F2F;
-    --color-red-02: #B71C1C;
-    --color-red-03: #E53935;
-    --color-red-04: #C62828;
+    --color-red-01: #F5A3A3;
+    --color-red-02: #EF7B7B;
+    --color-red-03: #F28C8C;
+    --color-red-04: #E86A6A;
+    --color-red-05: #F14C4C;
+    --color-red-06: #C74E39;
+    --color-red-07: #FF0000;
+    --color-red-08: #782626;

    /* ===================================
       Accent Colors - Green (color-green-*)
       =================================== */
-    --color-green-01: #388E3C;
-    --color-green-02: #2E7D32;
-    --color-green-03: #1B5E20;
-    --color-green-04: #4CAF50;
-    --color-green-05: #43A047;
+    --color-green-01: #A5D6A7;
+    --color-green-02: #81C784;
+    --color-green-03: #66BB6A;
+    --color-green-04: #B8E6B9;
+    --color-green-05: #98D99A;

    /* ===================================
       Accent Colors - Purple (color-purple-*)
       =================================== */
-    --color-purple-01: #7B1FA2;
-    --color-purple-02: #6A1B9A;
-    --color-purple-03: #9C27B0;
-    --color-purple-04: #8E24AA;
+    --color-purple-01: #CE93D8;
+    --color-purple-02: #BA68C8;
+    --color-purple-03: #D1A3DB;
+    --color-purple-04: #C280CE;

    /* ===================================
       Accent Colors - Yellow (color-yellow-*)
       =================================== */
-    --color-yellow-01: #F9A825;
-    --color-yellow-02: #F57F17;
-    --color-yellow-03: #FF8F00;
-    --color-yellow-04: #FF6F00;
-    --color-yellow-05: #FFD600;
+    --color-yellow-01: #FFE082;
+    --color-yellow-02: #FFD54F;
+    --color-yellow-03: #FFCA28;
+    --color-yellow-04: #FFC107;
+    --color-yellow-05: #FFF176;

    /* ===================================
       Accent Colors - Orange (color-orange-*)
       =================================== */
-    --color-orange-01: #E65100;
-    --color-orange-02: #EF6C00;
-    --color-orange-03: #F57C00;
+    --color-orange-01: #FFAB91;
+    --color-orange-02: #FF9A76;
+    --color-orange-03: #FFB74D;

    /* ===================================
       Gray Colors (color-gray-*)
@@ -113,17 +110,17 @@
    /* ===================================
       Seti Colors (color-seti-*)
       =================================== */
-    --color-seti-blue: #1976D2;
-    --color-seti-green: #689F38;
-    --color-seti-orange: #E65100;
-    --color-seti-pink: #D81B60;
-    --color-seti-red: #C62828;
-    --color-seti-steel: #455A64;
-    --color-seti-yellow: #F9A825;
-    --color-seti-purple: #7B1FA2;
-    --color-seti-ignore: #78909C;
+    --color-seti-blue: #64B5F6;
+    --color-seti-green: #AED581;
+    --color-seti-orange: #FFAB91;
+    --color-seti-pink: #F48FB1;
+    --color-seti-red: #EF9A9A;
+    --color-seti-steel: #90A4AE;
+    --color-seti-yellow: #FFE082;
+    --color-seti-purple: #CE93D8;
+    --color-seti-ignore: #B0BEC5;
    --color-seti-white: #ECEFF1;
-    --color-seti-gray: #607D8B;
+    --color-seti-gray: #90A4AE;

    /* ===================================
       Semantic Colors - Text (color-text-*)
@@ -143,7 +140,7 @@
       =================================== */
    --color-bg-base: var(--color-base-01);
    --color-bg-secondary: var(--color-base-03);
-    --color-bg-tertiary: var(--color-base-08);
+    --color-bg-tertiary: var(--color-base-06);
    --color-bg-elevated: var(--color-base-02);
    --color-bg-modal: var(--color-base-02);
    --color-bg-panel: var(--color-base-01);
@@ -167,35 +164,35 @@
    --color-btn-hover: var(--color-base-05);
    --color-btn-pressed: var(--color-base-06);
    --color-btn-disabled: var(--color-base-03);
-    --color-btn-primary: var(--color-blue-02);
-    --color-btn-primary-hover: var(--color-blue-03);
+    --color-btn-primary: var(--color-blue-03);
+    --color-btn-primary-hover: var(--color-blue-04);
    --color-btn-secondary: var(--color-base-05);
    --color-btn-secondary-hover: var(--color-base-06);

    /* ===================================
       Semantic Colors - Calendar (color-calendar-*)
       =================================== */
-    --color-calendar-sunday: var(--color-red-01);
-    --color-calendar-saturday: var(--color-blue-02);
-    --color-calendar-today: var(--color-orange-02);
+    --color-calendar-sunday: var(--color-red-05);
+    --color-calendar-saturday: var(--color-blue-05);
+    --color-calendar-today: var(--color-green-02);
    --color-calendar-selected: var(--color-blue-02);
-    --color-calendar-range: rgba(66, 133, 244, 0.15);
-    --color-calendar-range-hover: rgba(66, 133, 244, 0.25);
+    --color-calendar-range: var(--color-blue-02);
+    --color-calendar-range-hover: var(--color-blue-03);

    /* ===================================
       Semantic Colors - State (color-state-*)
       =================================== */
-    --color-state-success: var(--color-green-01);
+    --color-state-success: var(--color-green-02);
    --color-state-warning: var(--color-orange-02);
-    --color-state-error: var(--color-red-01);
-    --color-state-info: var(--color-blue-02);
+    --color-state-error: var(--color-red-03);
+    --color-state-info: var(--color-blue-04);

    /* ===================================
       Semantic Colors - Vector (color-vector-*)
       =================================== */
-    --color-vector-x: rgba(200, 60, 60, 1);
-    --color-vector-y: rgba(60, 160, 60, 1);
-    --color-vector-z: rgba(60, 60, 200, 1);
+    --color-vector-x: rgba(239, 130, 130, 1);
+    --color-vector-y: rgba(130, 210, 130, 1);
+    --color-vector-z: rgba(130, 150, 239, 1);

    /* ===================================
       Semantic Colors - Scrollbar (color-scroller-*)
@@ -216,8 +213,8 @@
       =================================== */
    --color-collection-item: rgba(255, 255, 255, 0);
    --color-collection-item-hover: var(--color-base-04);
-    --color-collection-item-selected: var(--color-blue-light-01);
-    --color-collection-item-selected-hover: var(--color-blue-light-02);
+    --color-collection-item-selected: var(--color-blue-04);
+    --color-collection-item-selected-hover: var(--color-blue-05);
    
   /* ===================================
       Semantic Colors - Tree Checkmark (color-tree-checkmark-*)
--- a/Assets/Resources/UIToolkit/Window/UTKTreeListWindow.uxml
+++ b/Assets/Resources/UIToolkit/Window/UTKTreeListWindow.uxml
@@ -6,7 +6,7 @@
            <utk:UTKButton name="close-btn" variant="Text" icon-only="true" class="tree-window-close-button" />
        </ui:VisualElement>
        <ui:VisualElement name="search-container" class="search-container">
-            <utk:UTKInputField name="search-field" placeholder-text="검색" class="search-field" />
+            <utk:UTKInputField name="search-field" placeholder-text="Search..." class="search-field" />
            <utk:UTKButton name="clear-btn" class="search-clear-button" variant="Text" icon="Close" icon-size="12" icon-only="true" />
        </ui:VisualElement>
        <ui:TreeView name="main-tree-view" view-data-key="model-tree-view" fixed-item-height="20" auto-expand="false" item-template="project://database/Assets/Resources/UIToolkit/List/UTKTreeListItem.uxml" horizontal-scrolling="true" selection-type="Multiple" style="flex-grow: 1;" />
--- a/Assets/Sample/UIToolkit/UTKPropertyListWindowSample.cs
+++ b/Assets/Sample/UIToolkit/UTKPropertyListWindowSample.cs
@@ -96,6 +96,10 @@ namespace UVC.Sample.UIToolkit
            _propertyWindow.OnPropertyButtonClicked += (id, actionName) =>
            {
                Debug.Log($"Button Clicked: {id} - Action: {actionName}");
+                if(id == "string_with_btn" && actionName == "string_action")
+                {
+                    _propertyWindow.SetPropertyValue("string_with_btn", "Button clicked!");
+                }
            };

            // 샘플 데이터 생성
--- a/Assets/Sample/UIToolkit/UTKStyleGuideSample.Input.cs
+++ b/Assets/Sample/UIToolkit/UTKStyleGuideSample.Input.cs
@@ -15,6 +15,45 @@ public partial class UTKStyleGuideSample

    private void InitializeInputFieldSample(VisualElement root)
    {
+        // Validation - Email
+        var emailInput = root.Q<UTKInputField>("input-validation-email");
+        if (emailInput != null)
+        {
+            emailInput.ErrorMessage = "올바른 이메일 형식이 아닙니다.";
+            emailInput.Validation = () => emailInput.Value.Contains("@") && emailInput.Value.Contains(".");
+        }
+
+        // Validation - Required
+        var requiredInput = root.Q<UTKInputField>("input-validation-required");
+        if (requiredInput != null)
+        {
+            requiredInput.ErrorMessage = "이름은 필수 항목입니다.";
+            requiredInput.Validation = () => !string.IsNullOrWhiteSpace(requiredInput.Value);
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var emailValid = emailInput?.Validate() ?? true;
+                var nameValid = requiredInput?.Validate() ?? true;
+                var allValid = emailValid && nameValid;
+                Debug.Log($"Validation: {(allValid ? "All Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                emailInput?.ClearError();
+                requiredInput?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 입력 필드
 var input = new UTKInputField();
@@ -27,10 +66,6 @@ var password = new UTKInputField();
 password.label = ""비밀번호"";
 password.isPasswordField = true;

-// 검증 오류 표시
-input.ErrorMessage = ""이름은 필수입니다."";
-input.ErrorMessage = """";  // 오류 제거
-
 // 변형 스타일
 input.Variant = UTKInputField.InputFieldVariant.Outlined;

@@ -39,13 +74,34 @@ input.OnFocused += () => Debug.Log(""포커스"");
 input.OnBlurred += () => Debug.Log(""포커스 해제"");
 input.OnSubmit += (value) => Debug.Log($""제출: {value}"");

-// 비활성화
+// ── Validation (입력 검증) ──────────────────────
+// 1) ErrorMessage + Validation 함수 설정
+var emailInput = new UTKInputField(""이메일"", ""example@email.com"");
+emailInput.ErrorMessage = ""올바른 이메일 형식이 아닙니다."";
+emailInput.Validation = () => emailInput.Value.Contains(""@"");
+// → Submit(Enter) 또는 FocusOut 시 자동 검증
+// → 실패: 붉은 외곽선 + 에러 메시지 표시
+// → 통과: 에러 상태 자동 해제
+
+// 2) 필수 입력 검증
+var nameInput = new UTKInputField(""이름"");
+nameInput.ErrorMessage = ""이름은 필수 항목입니다."";
+nameInput.Validation = () => !string.IsNullOrWhiteSpace(nameInput.Value);
+
+// 3) 강제 검증 호출 (폼 제출 버튼 등에서 사용)
+bool isValid = nameInput.Validate();  // Validation 실행 + UI 업데이트
+if (!isValid) return;
+
+// 4) 에러 수동 해제
+nameInput.ClearError();
+
+// 5) 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+input.ErrorMessage = ""서버 오류가 발생했습니다."";
+input.ErrorMessage = """";  // 오류 제거
+
+// 비활성화 / 읽기 전용
 input.IsEnabled = false;
-
-// 읽기 전용
 input.isReadOnly = true;
-
-// 여러 줄 입력
 input.multiline = true;",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">
@@ -62,6 +118,9 @@ input.multiline = true;",
 <!-- 여러 줄 입력 -->
 <utk:UTKInputField label=""설명"" multiline=""true"" />

+<!-- 에러 메시지 설정 (C#에서 Validation 설정 권장) -->
+<utk:UTKInputField label=""이메일"" error-message=""올바른 이메일 형식이 아닙니다."" />
+
 <!-- 비활성화 -->
 <utk:UTKInputField label=""읽기전용"" is-enabled=""false"" value=""수정 불가"" />

@@ -70,21 +129,78 @@ input.multiline = true;",

    private void InitializeIntegerFieldSample(VisualElement root)
    {
+        // Validation - Range (1~150)
+        var rangeField = root.Q<UTKIntegerField>("int-validation-range");
+        if (rangeField != null)
+        {
+            rangeField.ErrorMessage = "나이는 1~150 사이여야 합니다.";
+            rangeField.Validation = () => rangeField.Value >= 1 && rangeField.Value <= 150;
+        }
+
+        // Validation - Positive Only
+        var positiveField = root.Q<UTKIntegerField>("int-validation-positive");
+        if (positiveField != null)
+        {
+            positiveField.ErrorMessage = "수량은 0보다 커야 합니다.";
+            positiveField.Validation = () => positiveField.Value > 0;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("int-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var rangeValid = rangeField?.Validate() ?? true;
+                var positiveValid = positiveField?.Validate() ?? true;
+                var allValid = rangeValid && positiveValid;
+                Debug.Log($"IntegerField Validation: {(allValid ? "All Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                rangeField?.ClearError();
+                positiveField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 정수 필드
 var intField = new UTKIntegerField(""나이"");
 intField.Value = 25;
 intField.OnValueChanged += (value) => Debug.Log($""나이: {value}"");

-// 범위 제한 (이벤트로 처리)
-intField.OnValueChanged += (value) =>
-{
-    if (value < 0) intField.Value = 0;
-    if (value > 150) intField.Value = 150;
-};
-
 // 비활성화
-intField.IsEnabled = false;",
+intField.IsEnabled = false;
+
+// ── Validation (입력 검증) ──────────────────────
+// 1) ErrorMessage + Validation 함수 설정
+var ageField = new UTKIntegerField(""나이"", 0);
+ageField.ErrorMessage = ""나이는 1~150 사이여야 합니다."";
+ageField.Validation = () => ageField.Value >= 1 && ageField.Value <= 150;
+// → FocusOut 또는 Enter 시 자동 검증
+// → 실패: 붉은 외곽선 + 에러 메시지 표시
+// → 통과: 에러 상태 자동 해제
+
+// 2) 양수만 허용
+var qtyField = new UTKIntegerField(""수량"", 0);
+qtyField.ErrorMessage = ""수량은 0보다 커야 합니다."";
+qtyField.Validation = () => qtyField.Value > 0;
+
+// 3) 강제 검증 호출 (폼 제출 버튼 등에서 사용)
+bool isValid = ageField.Validate();  // Validation 실행 + UI 업데이트
+if (!isValid) return;
+
+// 4) 에러 수동 해제
+ageField.ClearError();
+
+// 5) 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+intField.ErrorMessage = ""서버 오류가 발생했습니다."";
+intField.ErrorMessage = """";  // 오류 제거",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -102,6 +218,45 @@ intField.IsEnabled = false;",

    private void InitializeLongFieldSample(VisualElement root)
    {
+        // Validation - Range (0 ~ 1,000,000)
+        var rangeField = root.Q<UTKLongField>("long-validation-range");
+        if (rangeField != null)
+        {
+            rangeField.ErrorMessage = "파일 크기는 0 ~ 1,000,000 사이여야 합니다.";
+            rangeField.Validation = () => rangeField.Value >= 0 && rangeField.Value <= 1000000;
+        }
+
+        // Validation - Positive Only
+        var positiveField = root.Q<UTKLongField>("long-validation-positive");
+        if (positiveField != null)
+        {
+            positiveField.ErrorMessage = "개수는 0보다 커야 합니다.";
+            positiveField.Validation = () => positiveField.Value > 0;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("long-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var rangeValid = rangeField?.Validate() ?? true;
+                var positiveValid = positiveField?.Validate() ?? true;
+                var allValid = rangeValid && positiveValid;
+                Debug.Log($"LongField Validation: {(allValid ? "All Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                rangeField?.ClearError();
+                positiveField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 Long 필드
 var longField = new UTKLongField(""파일 크기"");
@@ -109,7 +264,19 @@ longField.Value = 1073741824; // 1GB
 longField.OnValueChanged += (value) => Debug.Log($""크기: {value} bytes"");

 // 비활성화
-longField.IsEnabled = false;",
+longField.IsEnabled = false;
+
+// ── Validation (입력 검증) ──────────────────────
+// 1) ErrorMessage + Validation 함수 설정
+var sizeField = new UTKLongField(""파일 크기"", 0);
+sizeField.ErrorMessage = ""파일 크기는 0 ~ 1,000,000 사이여야 합니다."";
+sizeField.Validation = () => sizeField.Value >= 0 && sizeField.Value <= 1000000;
+
+// 2) 강제 검증 호출
+bool isValid = sizeField.Validate();
+
+// 3) 에러 수동 해제
+sizeField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -127,21 +294,66 @@ longField.IsEnabled = false;",

    private void InitializeFloatFieldSample(VisualElement root)
    {
+        // Validation - Range (0 ~ 100)
+        var rangeField = root.Q<UTKFloatField>("float-validation-range");
+        if (rangeField != null)
+        {
+            rangeField.ErrorMessage = "속도는 0 ~ 100 사이여야 합니다.";
+            rangeField.Validation = () => rangeField.Value >= 0f && rangeField.Value <= 100f;
+        }
+
+        // Validation - Positive Only
+        var positiveField = root.Q<UTKFloatField>("float-validation-positive");
+        if (positiveField != null)
+        {
+            positiveField.ErrorMessage = "무게는 0보다 커야 합니다.";
+            positiveField.Validation = () => positiveField.Value > 0f;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("float-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var rangeValid = rangeField?.Validate() ?? true;
+                var positiveValid = positiveField?.Validate() ?? true;
+                var allValid = rangeValid && positiveValid;
+                Debug.Log($"FloatField Validation: {(allValid ? "All Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                rangeField?.ClearError();
+                positiveField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 Float 필드
 var floatField = new UTKFloatField(""속도"");
 floatField.Value = 9.8f;
 floatField.OnValueChanged += (value) => Debug.Log($""속도: {value}"");

-// 범위 제한 (이벤트로 처리)
-floatField.OnValueChanged += (value) =>
-{
-    if (value < 0f) floatField.Value = 0f;
-    if (value > 100f) floatField.Value = 100f;
-};
-
 // 비활성화
-floatField.IsEnabled = false;",
+floatField.IsEnabled = false;
+
+// ── Validation (입력 검증) ──────────────────────
+// 1) ErrorMessage + Validation 함수 설정
+var speedField = new UTKFloatField(""속도"", 0f);
+speedField.ErrorMessage = ""속도는 0 ~ 100 사이여야 합니다."";
+speedField.Validation = () => speedField.Value >= 0f && speedField.Value <= 100f;
+// → FocusOut 또는 Enter 시 자동 검증
+
+// 2) 강제 검증 호출
+bool isValid = speedField.Validate();
+
+// 3) 에러 수동 해제
+speedField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -159,6 +371,45 @@ floatField.IsEnabled = false;",

    private void InitializeDoubleFieldSample(VisualElement root)
    {
+        // Validation - Range (0.0 ~ 100.0)
+        var rangeField = root.Q<UTKDoubleField>("double-validation-range");
+        if (rangeField != null)
+        {
+            rangeField.ErrorMessage = "값은 0.0 ~ 100.0 사이여야 합니다.";
+            rangeField.Validation = () => rangeField.Value >= 0.0 && rangeField.Value <= 100.0;
+        }
+
+        // Validation - Positive Only
+        var positiveField = root.Q<UTKDoubleField>("double-validation-positive");
+        if (positiveField != null)
+        {
+            positiveField.ErrorMessage = "거리는 0보다 커야 합니다.";
+            positiveField.Validation = () => positiveField.Value > 0.0;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("double-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var rangeValid = rangeField?.Validate() ?? true;
+                var positiveValid = positiveField?.Validate() ?? true;
+                var allValid = rangeValid && positiveValid;
+                Debug.Log($"DoubleField Validation: {(allValid ? "All Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                rangeField?.ClearError();
+                positiveField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 Double 필드
 var doubleField = new UTKDoubleField(""정밀도"");
@@ -166,7 +417,20 @@ doubleField.Value = 3.141592653589793;
 doubleField.OnValueChanged += (value) => Debug.Log($""값: {value}"");

 // 비활성화
-doubleField.IsEnabled = false;",
+doubleField.IsEnabled = false;
+
+// ── Validation (입력 검증) ──────────────────────
+// 1) ErrorMessage + Validation 함수 설정
+var percentField = new UTKDoubleField(""퍼센트"", 0);
+percentField.ErrorMessage = ""값은 0.0 ~ 100.0 사이여야 합니다."";
+percentField.Validation = () => percentField.Value >= 0.0 && percentField.Value <= 100.0;
+// → FocusOut 또는 Enter 시 자동 검증
+
+// 2) 강제 검증 호출
+bool isValid = percentField.Validate();
+
+// 3) 에러 수동 해제
+percentField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -193,6 +457,39 @@ doubleField.IsEnabled = false;",
            disabledRow.Add(stepper);
        }

+        // Validation - Even Number Only
+        UTKIntStepper? validationStepper = null;
+        var validationRow = root.Q<VisualElement>("stepper-validation-row");
+        if (validationRow != null)
+        {
+            validationStepper = new UTKIntStepper(0, 100, 1, 1);
+            validationStepper.style.width = 150;
+            validationStepper.ErrorMessage = "짝수만 입력 가능합니다.";
+            validationStepper.Validation = () => validationStepper.Value % 2 == 0;
+            validationRow.Add(validationStepper);
+            validationStepper.Validate();
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("stepper-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationStepper?.Validate() ?? true;
+                Debug.Log($"IntStepper Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationStepper?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 사용법
 var stepper = new UTKIntStepper(minValue: 0, maxValue: 100, value: 50, step: 1);
@@ -213,7 +510,15 @@ disabledStepper.SetEnabled(false);
 stepper.Value = 75;
 stepper.MinValue = 10;
 stepper.MaxValue = 90;
-stepper.Step = 2;",
+stepper.Step = 2;
+
+// ── Validation (입력 검증) ──────────────────────
+var evenStepper = new UTKIntStepper(0, 100, 0, 1);
+evenStepper.ErrorMessage = ""짝수만 입력 가능합니다."";
+evenStepper.Validation = () => evenStepper.Value % 2 == 0;
+
+bool isValid = evenStepper.Validate();
+evenStepper.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -232,6 +537,105 @@ stepper.Step = 2;",
 <!-- 커스텀 스타일 -->
 <utk:UTKIntStepper class=""custom-stepper"" style=""width: 150px;"" />

+</ui:UXML>");
+    }
+
+    private void InitializeFloatStepperSample(VisualElement root)
+    {
+        var disabledRow = root.Q<VisualElement>("float-stepper-disabled-row");
+        if (disabledRow != null)
+        {
+            var stepper = new UTKFloatStepper(0f, 10f, 3.5f, 0.1f);
+            stepper.style.width = 150;
+            stepper.SetEnabled(false);
+            disabledRow.Add(stepper);
+        }
+
+        // Validation - Non-Zero
+        UTKFloatStepper? validationStepper = null;
+        var validationRow = root.Q<VisualElement>("float-stepper-validation-row");
+        if (validationRow != null)
+        {
+            validationStepper = new UTKFloatStepper(0f, 10f, 0f, 0.1f);
+            validationStepper.style.width = 150;
+            validationStepper.ErrorMessage = "값은 0이 될 수 없습니다.";
+            validationStepper.Validation = () => validationStepper.Value != 0f;
+            validationRow.Add(validationStepper);
+            validationStepper.Validate();
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("float-stepper-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationStepper?.Validate() ?? true;
+                Debug.Log($"FloatStepper Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationStepper?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
+        SetCodeSamples(root,
+            csharpCode: @"// 기본 사용법
+var stepper = new UTKFloatStepper(minValue: 0f, maxValue: 10f, initialValue: 5.5f, step: 0.1f);
+stepper.OnValueChanged += (newValue) => Debug.Log($""Value: {newValue}"");
+
+// Step 설정
+var stepper05 = new UTKFloatStepper(0f, 10f, 2.5f, 0.5f); // Step 0.5씩 증감
+
+// Wrap Around (최소/최대값에서 순환)
+var wrapStepper = new UTKFloatStepper(0f, 1f, 0.5f, 0.1f);
+wrapStepper.WrapAround = true; // 0.0 -> -0.1 시 1.0으로 순환
+
+// 비활성화
+var disabledStepper = new UTKFloatStepper(0f, 10f, 3.5f, 0.1f);
+disabledStepper.SetEnabled(false);
+
+// 속성 변경
+stepper.Value = 7.5f;
+stepper.MinValue = 1f;
+stepper.MaxValue = 9f;
+stepper.Step = 0.25f;
+
+// 프로그래밍 방식으로 값 변경
+stepper.Increment();  // Step만큼 증가
+stepper.Decrement();  // Step만큼 감소
+stepper.SetValue(4.2f);  // 직접 설정
+
+// ── Validation (입력 검증) ──────────────────────
+var nonZeroStepper = new UTKFloatStepper(0f, 10f, 0f, 0.1f);
+nonZeroStepper.ErrorMessage = ""값은 0이 될 수 없습니다."";
+nonZeroStepper.Validation = () => nonZeroStepper.Value != 0f;
+
+bool isValid = nonZeroStepper.Validate();
+nonZeroStepper.ClearError();",
+            uxmlCode: @"<!-- 네임스페이스 선언 -->
+<ui:UXML xmlns:utk=""UVC.UIToolkit"">
+
+<!-- Step 0.1 -->
+<utk:UTKFloatStepper min-value=""0"" max-value=""10"" value=""5.5"" step=""0.1"" />
+
+<!-- Step 0.5 -->
+<utk:UTKFloatStepper min-value=""0"" max-value=""10"" value=""2.5"" step=""0.5"" />
+
+<!-- Wrap Around -->
+<utk:UTKFloatStepper min-value=""0"" max-value=""1"" value=""0.5"" step=""0.1"" wrap-around=""true"" />
+
+<!-- 비활성화 -->
+<utk:UTKFloatStepper min-value=""0"" max-value=""10"" value=""3.5"" step=""0.1"" is-enabled=""false"" />
+
+<!-- 커스텀 스타일 -->
+<utk:UTKFloatStepper class=""custom-stepper"" style=""width: 150px;"" />
+
 </ui:UXML>");
    }

@@ -243,6 +647,34 @@ stepper.Step = 2;",
            field.Value = new Vector2(100, 200);
        }

+        // Validation - Non-Zero
+        var validationField = root.Q<UTKVector2Field>("vec2-validation");
+        if (validationField != null)
+        {
+            validationField.ErrorMessage = "방향 벡터는 (0,0)이 될 수 없습니다.";
+            validationField.Validation = () => validationField.Value != Vector2.zero;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("vec2-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationField?.Validate() ?? true;
+                Debug.Log($"Vector2Field Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 사용법
 var positionField = new UTKVector2Field(""Position"");
@@ -255,7 +687,15 @@ field.label = """";

 // 읽기 전용
 var readOnlyField = new UTKVector2Field(""ReadOnly"");
-readOnlyField.SetEnabled(false);",
+readOnlyField.SetEnabled(false);
+
+// ── Validation (입력 검증) ──────────────────────
+var dirField = new UTKVector2Field(""Direction"");
+dirField.ErrorMessage = ""방향 벡터는 (0,0)이 될 수 없습니다."";
+dirField.Validation = () => dirField.Value != Vector2.zero;
+
+bool isValid = dirField.Validate();
+dirField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -279,6 +719,34 @@ readOnlyField.SetEnabled(false);",
            field.Value = new Vector3(10, 20, 30);
        }

+        // Validation - Non-Zero
+        var validationField = root.Q<UTKVector3Field>("vec3-validation");
+        if (validationField != null)
+        {
+            validationField.ErrorMessage = "스케일 벡터는 (0,0,0)이 될 수 없습니다.";
+            validationField.Validation = () => validationField.Value != Vector3.zero;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("vec3-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationField?.Validate() ?? true;
+                Debug.Log($"Vector3Field Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 사용법
 var positionField = new UTKVector3Field(""Position"");
@@ -291,7 +759,15 @@ rotationField.Value = new Vector3(0, 90, 0);

 // 비활성화
 var disabledField = new UTKVector3Field(""Disabled"");
-disabledField.SetEnabled(false);",
+disabledField.SetEnabled(false);
+
+// ── Validation (입력 검증) ──────────────────────
+var scaleField = new UTKVector3Field(""Scale"");
+scaleField.ErrorMessage = ""스케일 벡터는 (0,0,0)이 될 수 없습니다."";
+scaleField.Validation = () => scaleField.Value != Vector3.zero;
+
+bool isValid = scaleField.Validate();
+scaleField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -315,6 +791,42 @@ disabledField.SetEnabled(false);",
            field.Value = new Vector4(1, 0.5f, 0.25f, 1);
        }

+        // Validation - 0~1 Range (RGBA)
+        var validationField = root.Q<UTKVector4Field>("vec4-validation");
+        if (validationField != null)
+        {
+            validationField.Value = new Vector4(1, 0.5f, 0.25f, 1);
+            validationField.ErrorMessage = "RGBA 값은 모두 0~1 사이여야 합니다.";
+            validationField.Validation = () =>
+            {
+                var v = validationField.Value;
+                return v.x >= 0f && v.x <= 1f &&
+                       v.y >= 0f && v.y <= 1f &&
+                       v.z >= 0f && v.z <= 1f &&
+                       v.w >= 0f && v.w <= 1f;
+            };
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("vec4-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationField?.Validate() ?? true;
+                Debug.Log($"Vector4Field Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 사용법
 var colorField = new UTKVector4Field(""Color"");
@@ -328,7 +840,20 @@ quaternionField.Value = new Vector4(quat.x, quat.y, quat.z, quat.w);

 // 비활성화
 var disabledField = new UTKVector4Field(""Disabled"");
-disabledField.SetEnabled(false);",
+disabledField.SetEnabled(false);
+
+// ── Validation (입력 검증) ──────────────────────
+var rgbaField = new UTKVector4Field(""RGBA"");
+rgbaField.ErrorMessage = ""RGBA 값은 모두 0~1 사이여야 합니다."";
+rgbaField.Validation = () =>
+{
+    var v = rgbaField.Value;
+    return v.x >= 0f && v.x <= 1f && v.y >= 0f && v.y <= 1f
+        && v.z >= 0f && v.z <= 1f && v.w >= 0f && v.w <= 1f;
+};
+
+bool isValid = rgbaField.Validate();
+rgbaField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -352,6 +877,35 @@ disabledField.SetEnabled(false);",
            field.Value = new Rect(10, 20, 100, 50);
        }

+        // Validation - Positive Size
+        var validationField = root.Q<UTKRectField>("rect-validation");
+        if (validationField != null)
+        {
+            validationField.ErrorMessage = "Width와 Height는 0보다 커야 합니다.";
+            validationField.Validation = () =>
+                validationField.Value.width > 0 && validationField.Value.height > 0;
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("rect-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationField?.Validate() ?? true;
+                Debug.Log($"RectField Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 사용법
 var areaField = new UTKRectField(""Area"");
@@ -364,7 +918,16 @@ screenArea.Value = new Rect(0, 0, Screen.width, Screen.height);

 // 비활성화
 var disabledField = new UTKRectField(""Disabled"");
-disabledField.SetEnabled(false);",
+disabledField.SetEnabled(false);
+
+// ── Validation (입력 검증) ──────────────────────
+var viewportField = new UTKRectField(""Viewport"");
+viewportField.ErrorMessage = ""Width와 Height는 0보다 커야 합니다."";
+viewportField.Validation = () =>
+    viewportField.Value.width > 0 && viewportField.Value.height > 0;
+
+bool isValid = viewportField.Validate();
+viewportField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

@@ -388,6 +951,38 @@ disabledField.SetEnabled(false);",
            field.Value = new Bounds(new Vector3(0, 1, 0), new Vector3(2, 2, 2));
        }

+        // Validation - Positive Extents
+        var validationField = root.Q<UTKBoundsField>("bounds-validation");
+        if (validationField != null)
+        {
+            validationField.ErrorMessage = "Extents는 모두 0보다 커야 합니다.";
+            validationField.Validation = () =>
+            {
+                var ext = validationField.Value.extents;
+                return ext.x > 0f && ext.y > 0f && ext.z > 0f;
+            };
+        }
+
+        // Validate All / Clear Errors 버튼
+        var buttonRow = root.Q<VisualElement>("bounds-validation-button-row");
+        if (buttonRow != null)
+        {
+            var validateBtn = new UTKButton("Validate All", variant: UTKButton.ButtonVariant.Primary);
+            validateBtn.OnClicked += () =>
+            {
+                var isValid = validationField?.Validate() ?? true;
+                Debug.Log($"BoundsField Validation: {(isValid ? "Passed" : "Has Errors")}");
+            };
+            buttonRow.Add(validateBtn);
+
+            var clearBtn = new UTKButton("Clear Errors");
+            clearBtn.OnClicked += () =>
+            {
+                validationField?.ClearError();
+            };
+            buttonRow.Add(clearBtn);
+        }
+
        SetCodeSamples(root,
            csharpCode: @"// 기본 사용법
 var boundsField = new UTKBoundsField(""Bounds"");
@@ -402,7 +997,19 @@ collisionField.Value = new Bounds(Vector3.zero, Vector3.one * 5);

 // 비활성화
 var disabledField = new UTKBoundsField(""Disabled"");
-disabledField.SetEnabled(false);",
+disabledField.SetEnabled(false);
+
+// ── Validation (입력 검증) ──────────────────────
+var colliderField = new UTKBoundsField(""Collider"");
+colliderField.ErrorMessage = ""Extents는 모두 0보다 커야 합니다."";
+colliderField.Validation = () =>
+{
+    var ext = colliderField.Value.extents;
+    return ext.x > 0f && ext.y > 0f && ext.z > 0f;
+};
+
+bool isValid = colliderField.Validate();
+colliderField.ClearError();",
            uxmlCode: @"<!-- 네임스페이스 선언 -->
 <ui:UXML xmlns:utk=""UVC.UIToolkit"">

--- a/Assets/Sample/UIToolkit/UTKStyleGuideSample.cs
+++ b/Assets/Sample/UIToolkit/UTKStyleGuideSample.cs
@@ -68,6 +68,7 @@ public partial class UTKStyleGuideSample : MonoBehaviour
        ["UTKRectField"] = "UIToolkit/Sample/Input/UTKRectFieldSample",
        ["UTKBoundsField"] = "UIToolkit/Sample/Input/UTKBoundsFieldSample",
        ["UTKIntStepper"] = "UIToolkit/Sample/Input/UTKIntStepperSample",
+        ["UTKFloatStepper"] = "UIToolkit/Sample/Input/UTKFloatStepperSample",
        // Slider
        ["UTKSlider"] = "UIToolkit/Sample/Slider/UTKSliderSample",
        ["UTKSliderInt"] = "UIToolkit/Sample/Slider/UTKSliderIntSample",
@@ -111,7 +112,7 @@ public partial class UTKStyleGuideSample : MonoBehaviour
    {
        ["Icon"] = new[] { "UTKMaterialIcons", "UTKImageIcons", "UTKImage" },
        ["Button"] = new[] { "UTKButton", "UTKCheckBox", "UTKToggle", "UTKRadioButton", "UTKToggleButtonGroup" },
-        ["Input"] = new[] { "UTKInputField", "UTKIntegerField", "UTKLongField", "UTKFloatField", "UTKDoubleField", "UTKVector2Field", "UTKVector3Field", "UTKVector4Field", "UTKRectField", "UTKBoundsField", "UTKIntStepper" },
+        ["Input"] = new[] { "UTKInputField", "UTKIntegerField", "UTKLongField", "UTKFloatField", "UTKDoubleField", "UTKVector2Field", "UTKVector3Field", "UTKVector4Field", "UTKRectField", "UTKBoundsField", "UTKIntStepper", "UTKFloatStepper" },
        ["Slider"] = new[] { "UTKSlider", "UTKSliderInt", "UTKMinMaxSlider", "UTKProgressBar" },
        ["Dropdown"] = new[] { "UTKDropdown", "UTKEnumDropDown", "UTKMultiSelectDropdown" },
        ["Label"] = new[] { "UTKLabel", "UTKHelpBox" },
@@ -451,6 +452,9 @@ public partial class UTKStyleGuideSample : MonoBehaviour
            case "UTKIntStepper":
                InitializeNumberStepperSample(root);
                break;
+            case "UTKFloatStepper":
+                InitializeFloatStepperSample(root);
+                break;
            case "UTKVector2Field":
                InitializeVector2FieldSample(root);
                break;
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKBoundsField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKBoundsField.cs
@@ -16,6 +16,10 @@ namespace UVC.UIToolkit
    /// <para>- Center: 경계 상자의 중심점 (Vector3)</para>
    /// <para>- Extents: 중심에서 각 축 방향으로의 거리 (Vector3), Size의 절반 값</para>
    /// <para>- Size: 경계 상자의 전체 크기 (Extents * 2)</para>
+    /// <list type="bullet">
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
+    /// </list>
    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
@@ -52,6 +56,26 @@ namespace UVC.UIToolkit
    /// readOnlyField.Value = new Bounds(Vector3.zero, Vector3.one);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var boundsField = new UTKBoundsField("경계");
+    /// boundsField.ErrorMessage = "크기는 양수여야 합니다.";
+    /// boundsField.Validation = () => boundsField.Value.size.x > 0 &amp;&amp; boundsField.Value.size.y > 0 &amp;&amp; boundsField.Value.size.z > 0;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = boundsField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// boundsField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// boundsField.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// boundsField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code>
    /// <!-- 네임스페이스 선언 -->
@@ -70,6 +94,9 @@ namespace UVC.UIToolkit
    ///
    ///     <!-- 읽기 전용 -->
    ///     <utk:UTKBoundsField label="고정 경계" is-readonly="true" />
+    ///
+    ///     <!-- 에러 메시지 (C#에서 Validation 설정 권장) -->
+    ///     <utk:UTKBoundsField label="경계" error-message="크기는 양수여야 합니다." />
    /// </UXML>
    /// </code>
    /// <para><b>실제 활용 예시:</b></para>
@@ -102,6 +129,9 @@ namespace UVC.UIToolkit
        private string _xLabel = "X";
        private string _yLabel = "Y";
        private string _zLabel = "Z";
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -202,6 +232,27 @@ namespace UVC.UIToolkit
                EnableInClassList("utk-boundsfield--readonly", value);
            }
        }
+
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-boundsfield--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
        #endregion

        #region Constructor
@@ -238,6 +289,7 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Bounds>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
        }

        private void SubscribeToThemeChanges()
@@ -303,6 +355,73 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-boundsfield--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-boundsfield--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-boundsfield__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -314,8 +433,11 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<Bounds>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKDoubleField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKDoubleField.cs
@@ -17,6 +17,8 @@ namespace UVC.UIToolkit
    ///   <item><description>과학 계산, 금융 데이터, 정밀 측정값에 사용</description></item>
    ///   <item><description>float보다 약 2배 정밀도 (유효숫자 15-17자리)</description></item>
    ///   <item><description>일반 게임 로직에는 UTKFloatField로 충분</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
    /// </list>
    /// <para><b>float vs double:</b></para>
    /// <list type="bullet">
@@ -44,6 +46,20 @@ namespace UVC.UIToolkit
    /// double currentValue = doubleField.Value;
    /// doubleField.Value = 127.9780;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var precisionField = new UTKDoubleField("정밀 값", 0);
+    /// precisionField.ErrorMessage = "값은 0보다 커야 합니다.";
+    /// precisionField.Validation = () => precisionField.Value > 0;
+    /// // → FocusOut 시 자동으로 검증
+    ///
+    /// // 강제 검증 호출
+    /// bool isValid = precisionField.Validate();
+    ///
+    /// // 에러 수동 해제
+    /// precisionField.ClearError();
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 Double 필드 -->
@@ -72,6 +88,9 @@ namespace UVC.UIToolkit
        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -87,6 +106,27 @@ namespace UVC.UIToolkit
            set => this.value = value;
        }

+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-double-field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+
        /// <summary>활성화 상태</summary>
        [UxmlAttribute("is-enabled")]
        public bool IsEnabled
@@ -133,6 +173,8 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<double>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
+            RegisterCallback<KeyDownEvent>(OnKeyDown, TrickleDown.TrickleDown);
        }

        private void SubscribeToThemeChanges()
@@ -165,6 +207,81 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+
+        private void OnKeyDown(KeyDownEvent evt)
+        {
+            if (evt.keyCode == KeyCode.Return)
+            {
+                RunValidation();
+            }
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-double-field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-double-field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-double-field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -176,8 +293,12 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<double>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            UnregisterCallback<KeyDownEvent>(OnKeyDown);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKFloatField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKFloatField.cs
@@ -18,6 +18,8 @@ namespace UVC.UIToolkit
    ///   <item><description>가격, 속도, 거리 등 실수 값에 적합</description></item>
    ///   <item><description>더 높은 정밀도가 필요하면 UTKDoubleField 사용</description></item>
    ///   <item><description>정수만 필요하면 UTKIntegerField 사용</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
    /// </list>
    /// <para><b>주의:</b> float 리터럴은 숫자 뒤에 'f'를 붙여야 합니다 (예: 3.14f)</para>
    /// </remarks>
@@ -44,6 +46,31 @@ namespace UVC.UIToolkit
    /// // 비활성화
    /// floatField.IsEnabled = false;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var speedField = new UTKFloatField("속도", 0f);
+    /// speedField.ErrorMessage = "속도는 0보다 커야 합니다.";
+    /// speedField.Validation = () => speedField.Value > 0f;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 범위 검증
+    /// var temperatureField = new UTKFloatField("온도", 20f);
+    /// temperatureField.ErrorMessage = "온도는 -40 ~ 60 사이여야 합니다.";
+    /// temperatureField.Validation = () => temperatureField.Value >= -40f &amp;&amp; temperatureField.Value &lt;= 60f;
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = speedField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// speedField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// floatField.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// floatField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 실수 필드 -->
@@ -56,6 +83,8 @@ namespace UVC.UIToolkit
    /// <code>
    /// // 캐릭터 이동 속도 편집
    /// var moveSpeedField = new UTKFloatField("이동 속도", character.MoveSpeed);
+    /// moveSpeedField.ErrorMessage = "이동 속도는 0 이상이어야 합니다.";
+    /// moveSpeedField.Validation = () => moveSpeedField.Value >= 0f;
    /// moveSpeedField.OnValueChanged += (newSpeed) => {
    ///     character.MoveSpeed = Mathf.Clamp(newSpeed, 0f, 100f);
    /// };
@@ -71,6 +100,9 @@ namespace UVC.UIToolkit
        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -86,6 +118,27 @@ namespace UVC.UIToolkit
            set => this.value = value;
        }

+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-float-field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+
        /// <summary>활성화 상태</summary>
        [UxmlAttribute("is-enabled")]
        public bool IsEnabled
@@ -132,6 +185,8 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<float>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
+            RegisterCallback<KeyDownEvent>(OnKeyDown, TrickleDown.TrickleDown);
        }

        private void SubscribeToThemeChanges()
@@ -164,6 +219,81 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+
+        private void OnKeyDown(KeyDownEvent evt)
+        {
+            if (evt.keyCode == KeyCode.Return)
+            {
+                RunValidation();
+            }
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-float-field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-float-field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-float-field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -175,8 +305,12 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<float>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            UnregisterCallback<KeyDownEvent>(OnKeyDown);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKFloatStepper.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKFloatStepper.cs
@@ -25,6 +25,12 @@ namespace UVC.UIToolkit
    ///   <item><description>증감 단위 설정 (Step)</description></item>
    ///   <item><description>순환 모드 (WrapAround) - 최대에서 최소로, 최소에서 최대로</description></item>
    /// </list>
+    /// <para><b>Validation (유효성 검사):</b></para>
+    /// <para>
+    /// <see cref="Validation"/> 속성에 검증 함수를 설정하면,
+    /// 포커스 아웃 시 자동으로 유효성 검사를 수행합니다.
+    /// 검증 실패 시 <see cref="ErrorMessage"/>에 설정된 메시지가 표시됩니다.
+    /// </para>
    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
@@ -56,6 +62,12 @@ namespace UVC.UIToolkit
    /// var readOnlyStepper = new UTKFloatStepper(0f, 10f, 5f, 0.1f);
    /// readOnlyStepper.IsReadOnly = true;
    /// </code>
+    /// <para><b>Validation 사용:</b></para>
+    /// <code>
+    /// var volumeStepper = new UTKFloatStepper(0f, 1f, 0.5f, 0.1f);
+    /// volumeStepper.ErrorMessage = "볼륨은 0~1 사이여야 합니다.";
+    /// volumeStepper.Validation = () => volumeStepper.Value >= 0f &amp;&amp; volumeStepper.Value &lt;= 1f;
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 스테퍼 -->
@@ -69,6 +81,9 @@ namespace UVC.UIToolkit
    ///
    /// <!-- 읽기 전용 -->
    /// <utk:UTKFloatStepper value="5.0" is-readonly="true" />
+    ///
+    /// <!-- 에러 메시지 설정 -->
+    /// <utk:UTKFloatStepper value="0.5" error-message="볼륨은 0~1 사이여야 합니다." />
    /// ]]></code>
    /// <para><b>실제 활용 예시 (볼륨 조절):</b></para>
    /// <code>
@@ -142,6 +157,20 @@ namespace UVC.UIToolkit
                EnableInClassList("utk-number-stepper--readonly", value);
            }
        }
+
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-number-stepper--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
        #endregion

        #region Fields
@@ -154,10 +183,29 @@ namespace UVC.UIToolkit
        private bool _wrapAround;
        private bool _isUpdating;
        private bool _isHovered;
+        private string _errorMessage = "";

        private TextField? _textField;
        private Button? _upButton;
        private Button? _downButton;
+
+        /// <summary>유효성 검사 함수. true 반환 시 유효, false 반환 시 에러 표시</summary>
+        private Func<bool>? _validation;
+
+        /// <summary>에러 메시지 표시용 레이블</summary>
+        private Label? _errorLabel;
+        #endregion
+
+        #region Properties
+        /// <summary>
+        /// 유효성 검사 함수.
+        /// 포커스 아웃 시 자동으로 호출되며, false 반환 시 에러 스타일과 메시지가 표시됩니다.
+        /// </summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
        #endregion

        #region Events
@@ -241,6 +289,7 @@ namespace UVC.UIToolkit
                if (notify)
                {
                    OnValueChanged?.Invoke(_value);
+                    RunValidation();
                }
            }
        }
@@ -288,6 +337,18 @@ namespace UVC.UIToolkit
        {
            _textField?.Focus();
        }
+
+        /// <summary>강제로 Validation을 실행하여 에러 상태를 업데이트합니다.</summary>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
        #endregion

        #region Private Methods - UI Creation
@@ -344,6 +405,7 @@ namespace UVC.UIToolkit

            _textField?.RegisterCallback<ChangeEvent<string>>(OnTextFieldChanged);
            _textField?.RegisterCallback<KeyDownEvent>(OnTextFieldKeyDown, TrickleDown.TrickleDown);
+            _textField?.RegisterCallback<FocusOutEvent>(OnTextFieldFocusOut);

            RegisterCallback<MouseEnterEvent>(OnMouseEnter);
            RegisterCallback<MouseLeaveEvent>(OnMouseLeave);
@@ -397,6 +459,12 @@ namespace UVC.UIToolkit
            }
        }

+        /// <summary>텍스트 필드 포커스 아웃 시 유효성 검사 실행</summary>
+        private void OnTextFieldFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+
        private void OnMouseEnter(MouseEnterEvent evt) => _isHovered = true;
        private void OnMouseLeave(MouseLeaveEvent evt) => _isHovered = false;

@@ -433,9 +501,25 @@ namespace UVC.UIToolkit

        private float ClampValueInternal(float value)
        {
+            // Step 소수점 자릿수 기준으로 반올림하여 부동소수점 오차 제거
+            // 예: step=0.1 → digits=1, 0.7+0.1=0.8000001 → 0.8
+            int digits = GetDecimalDigits(_step);
+            if (digits > 0)
+            {
+                value = (float)Math.Round(value, digits);
+            }
            return Mathf.Clamp(value, _minValue, _maxValue);
        }

+        /// <summary>소수점 이하 유효 자릿수를 반환합니다.</summary>
+        private static int GetDecimalDigits(float value)
+        {
+            // 최대 7자리까지 검사 (float 정밀도 한계)
+            string s = value.ToString("G7");
+            int dotIndex = s.IndexOf('.');
+            return dotIndex < 0 ? 0 : s.Length - dotIndex - 1;
+        }
+
        private void UpdateReadOnlyState()
        {
            if (_textField != null)
@@ -453,6 +537,47 @@ namespace UVC.UIToolkit
                _downButton.SetEnabled(!_isReadOnly);
            }
        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                EnableInClassList("utk-number-stepper--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                EnableInClassList("utk-number-stepper--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-number-stepper__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -471,6 +596,7 @@ namespace UVC.UIToolkit

            _textField?.UnregisterCallback<ChangeEvent<string>>(OnTextFieldChanged);
            _textField?.UnregisterCallback<KeyDownEvent>(OnTextFieldKeyDown, TrickleDown.TrickleDown);
+            _textField?.UnregisterCallback<FocusOutEvent>(OnTextFieldFocusOut);

            UnregisterCallback<MouseEnterEvent>(OnMouseEnter);
            UnregisterCallback<MouseLeaveEvent>(OnMouseLeave);
@@ -481,6 +607,10 @@ namespace UVC.UIToolkit
            OnTabPressed = null;
            OnShiftTabPressed = null;

+            // Validation 정리
+            _validation = null;
+            _errorLabel = null;
+
            // UI 참조 정리
            _textField = null;
            _upButton = null;
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKInputField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKInputField.cs
@@ -9,6 +9,15 @@ namespace UVC.UIToolkit
    /// 입력 필드 컴포넌트.
    /// Unity TextField를 래핑하여 커스텀 스타일을 적용합니다.
    /// </summary>
+    /// <remarks>
+    /// <para><b>주요 기능:</b></para>
+    /// <list type="bullet">
+    ///   <item><description>플레이스홀더, 비밀번호, 멀티라인 지원</description></item>
+    ///   <item><description>스타일 변형 (Default, Filled, Outlined)</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (Submit/FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
+    /// </list>
+    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
    /// <code>
@@ -17,39 +26,62 @@ namespace UVC.UIToolkit
    /// input.label = "이름";
    /// input.Placeholder = "이름을 입력하세요";
    /// input.OnValueChanged += (value) => Debug.Log($"입력값: {value}");
-    /// 
+    ///
    /// // 비밀번호 입력 필드
    /// var password = new UTKInputField();
    /// password.label = "비밀번호";
    /// password.isPasswordField = true;
-    /// 
-    /// // 검증 오류 표시
-    /// input.ErrorMessage = "이름은 필수입니다.";
-    /// // 오류 제거
-    /// input.ErrorMessage = "";
-    /// 
+    ///
    /// // 변형 스타일
    /// input.Variant = UTKInputField.InputFieldVariant.Outlined;
    /// </code>
-    /// <para><b>UXML에서 사용:</b></para>
+    /// <para><b>Validation (입력 검증):</b></para>
    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var emailInput = new UTKInputField("이메일", "example@email.com");
+    /// emailInput.ErrorMessage = "올바른 이메일 형식이 아닙니다.";
+    /// emailInput.Validation = () => emailInput.Value.Contains("@");
+    /// // → Submit(Enter) 또는 FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 필수 입력 검증
+    /// var nameInput = new UTKInputField("이름");
+    /// nameInput.ErrorMessage = "이름은 필수 항목입니다.";
+    /// nameInput.Validation = () => !string.IsNullOrWhiteSpace(nameInput.Value);
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = nameInput.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// nameInput.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이)
+    /// input.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// input.ErrorMessage = "";  // 오류 제거
+    /// </code>
+    /// <para><b>UXML에서 사용:</b></para>
+    /// <code><![CDATA[
    /// <ui:UXML xmlns:utk="UVC.UIToolkit">
    ///     <!-- 기본 입력 필드 -->
    ///     <utk:UTKInputField label="이름" />
-    ///     
+    ///
    ///     <!-- 플레이스홀더 -->
    ///     <utk:UTKInputField label="이메일" placeholder="example@email.com" />
-    ///     
+    ///
    ///     <!-- 비밀번호 필드 -->
    ///     <utk:UTKInputField label="비밀번호" is-password-field="true" />
-    ///     
+    ///
    ///     <!-- 여러 줄 입력 -->
    ///     <utk:UTKInputField label="설명" multiline="true" />
-    ///     
+    ///
+    ///     <!-- 에러 메시지 (C#에서 Validation 설정 권장) -->
+    ///     <utk:UTKInputField label="이메일" error-message="올바른 이메일 형식이 아닙니다." />
+    ///
    ///     <!-- 비활성화 -->
    ///     <utk:UTKInputField label="읽기전용" is-enabled="false" value="수정 불가" />
    /// </ui:UXML>
-    /// </code>
+    /// ]]></code>
    /// </example>
    [UxmlElement]
    public partial class UTKInputField : TextField, IDisposable
@@ -63,6 +95,8 @@ namespace UVC.UIToolkit
        private bool _isEnabled = true;
        private string _errorMessage = "";
        private InputFieldVariant _variant = InputFieldVariant.Default;
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -92,7 +126,7 @@ namespace UVC.UIToolkit
            set => textEdition.placeholder = value;
        }

-        /// <summary>에러 메시지</summary>
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
        [UxmlAttribute("error-message")]
        public string ErrorMessage
        {
@@ -100,10 +134,19 @@ namespace UVC.UIToolkit
            set
            {
                _errorMessage = value;
-                EnableInClassList("utk-input--error", !string.IsNullOrEmpty(value));
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-input--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
            }
        }

+        /// <summary>검증 함수. Submit/FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+
        /// <summary>활성화 상태</summary>
        [UxmlAttribute("is-enabled")]
        public bool IsEnabled
@@ -199,26 +242,9 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<string>>(OnTextValueChanged);
-
-            RegisterCallback<FocusInEvent>(_ =>
-            {
-                EnableInClassList("utk-input--focused", true);
-                OnFocused?.Invoke();
-            });
-
-            RegisterCallback<FocusOutEvent>(_ =>
-            {
-                EnableInClassList("utk-input--focused", false);
-                OnBlurred?.Invoke();
-            });
-
-            RegisterCallback<KeyDownEvent>(evt =>
-            {
-                if (evt.keyCode == KeyCode.Return && !multiline)
-                {
-                    OnSubmit?.Invoke(value);
-                }
-            }, TrickleDown.TrickleDown);
+            RegisterCallback<FocusInEvent>(OnFocusIn);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
+            RegisterCallback<KeyDownEvent>(OnKeyDown, TrickleDown.TrickleDown);
        }

        private void SubscribeToThemeChanges()
@@ -263,6 +289,28 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusIn(FocusInEvent evt)
+        {
+            EnableInClassList("utk-input--focused", true);
+            OnFocused?.Invoke();
+        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            EnableInClassList("utk-input--focused", false);
+            OnBlurred?.Invoke();
+            RunValidation();
+        }
+
+        private void OnKeyDown(KeyDownEvent evt)
+        {
+            if (evt.keyCode == KeyCode.Return && !multiline)
+            {
+                OnSubmit?.Invoke(value);
+                RunValidation();
+            }
+        }
        #endregion

        #region Methods
@@ -283,6 +331,15 @@ namespace UVC.UIToolkit
            }
        }

+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
        /// <summary>
        /// 선택 영역 설정
        /// </summary>
@@ -291,6 +348,57 @@ namespace UVC.UIToolkit
            textSelection.SelectAll();
        }

+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-input--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-input--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-input__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
+
        private void UpdateVariant()
        {
            RemoveFromClassList("utk-input--default");
@@ -318,10 +426,16 @@ namespace UVC.UIToolkit
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
            UnregisterCallback<ChangeEvent<string>>(OnTextValueChanged);
+            UnregisterCallback<FocusInEvent>(OnFocusIn);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            UnregisterCallback<KeyDownEvent>(OnKeyDown);
+
            OnValueChanged = null;
            OnFocused = null;
            OnBlurred = null;
            OnSubmit = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKIntStepper.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKIntStepper.cs
@@ -24,6 +24,8 @@ namespace UVC.UIToolkit
    ///   <item><description>최소/최대값 제한 (MinValue, MaxValue)</description></item>
    ///   <item><description>증감 단위 설정 (Step)</description></item>
    ///   <item><description>순환 모드 (WrapAround) - 최대에서 최소로, 최소에서 최대로</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
    /// </list>
    /// </remarks>
    /// <example>
@@ -79,6 +81,15 @@ namespace UVC.UIToolkit
    ///     UpdateCalendar(month);
    /// };
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// var monthStepper = new UTKIntStepper(1, 12, 1, 1);
+    /// monthStepper.ErrorMessage = "유효하지 않은 월입니다.";
+    /// monthStepper.Validation = () => monthStepper.Value >= 1 &amp;&amp; monthStepper.Value &lt;= 12;
+    ///
+    /// bool isValid = monthStepper.Validate();
+    /// monthStepper.ClearError();
+    /// </code>
    /// </example>
    [UxmlElement]
    public partial class UTKIntStepper : VisualElement, IDisposable
@@ -143,6 +154,20 @@ namespace UVC.UIToolkit
                EnableInClassList("utk-number-stepper--readonly", value);
            }
        }
+
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-number-stepper--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
        #endregion

        #region Fields
@@ -156,11 +181,24 @@ namespace UVC.UIToolkit
        private bool _isUpdating;
        private bool _isHovered;

+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
+
        private TextField? _textField;
        private Button? _upButton;
        private Button? _downButton;
        #endregion

+        #region Properties
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+        #endregion
+
        #region Events
        /// <summary>값이 변경될 때 발생</summary>
        public event Action<int>? OnValueChanged;
@@ -242,6 +280,7 @@ namespace UVC.UIToolkit
                if (notify)
                {
                    OnValueChanged?.Invoke(_value);
+                    RunValidation();
                }
            }
        }
@@ -289,6 +328,18 @@ namespace UVC.UIToolkit
        {
            _textField?.Focus();
        }
+
+        /// <summary>강제로 Validation을 실행하여 에러 상태를 업데이트합니다.</summary>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
        #endregion

        #region Private Methods - UI Creation
@@ -345,6 +396,7 @@ namespace UVC.UIToolkit

            _textField?.RegisterCallback<ChangeEvent<string>>(OnTextFieldChanged);
            _textField?.RegisterCallback<KeyDownEvent>(OnTextFieldKeyDown, TrickleDown.TrickleDown);
+            _textField?.RegisterCallback<FocusOutEvent>(OnTextFieldFocusOut);

            RegisterCallback<MouseEnterEvent>(OnMouseEnter);
            RegisterCallback<MouseLeaveEvent>(OnMouseLeave);
@@ -371,6 +423,11 @@ namespace UVC.UIToolkit
            }
        }

+        private void OnTextFieldFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+
        private void OnTextFieldKeyDown(KeyDownEvent evt)
        {
            if (evt.keyCode == KeyCode.UpArrow)
@@ -454,6 +511,47 @@ namespace UVC.UIToolkit
                _downButton.SetEnabled(!_isReadOnly);
            }
        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                EnableInClassList("utk-number-stepper--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                EnableInClassList("utk-number-stepper--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-number-stepper__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -472,6 +570,7 @@ namespace UVC.UIToolkit

            _textField?.UnregisterCallback<ChangeEvent<string>>(OnTextFieldChanged);
            _textField?.UnregisterCallback<KeyDownEvent>(OnTextFieldKeyDown, TrickleDown.TrickleDown);
+            _textField?.UnregisterCallback<FocusOutEvent>(OnTextFieldFocusOut);

            UnregisterCallback<MouseEnterEvent>(OnMouseEnter);
            UnregisterCallback<MouseLeaveEvent>(OnMouseLeave);
@@ -483,6 +582,8 @@ namespace UVC.UIToolkit
            OnShiftTabPressed = null;

            // UI 참조 정리
+            _validation = null;
+            _errorLabel = null;
            _textField = null;
            _upButton = null;
            _downButton = null;
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKIntegerField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKIntegerField.cs
@@ -17,6 +17,8 @@ namespace UVC.UIToolkit
    ///   <item><description>개수, 수량, 인덱스 등 정수 값에 사용</description></item>
    ///   <item><description>큰 숫자가 필요하면 UTKLongField 사용</description></item>
    ///   <item><description>소수점이 필요하면 UTKFloatField 사용</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
    /// </list>
    /// </remarks>
    /// <example>
@@ -42,6 +44,31 @@ namespace UVC.UIToolkit
    /// // 비활성화
    /// intField.IsEnabled = false;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var ageField = new UTKIntegerField("나이", 0);
+    /// ageField.ErrorMessage = "나이는 1~150 사이여야 합니다.";
+    /// ageField.Validation = () => ageField.Value >= 1 &amp;&amp; ageField.Value &lt;= 150;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 양수만 허용
+    /// var quantityField = new UTKIntegerField("수량", 0);
+    /// quantityField.ErrorMessage = "수량은 0보다 커야 합니다.";
+    /// quantityField.Validation = () => quantityField.Value > 0;
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = ageField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// ageField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// intField.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// intField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 정수 필드 -->
@@ -54,8 +81,10 @@ namespace UVC.UIToolkit
    /// <code>
    /// // 인벤토리 아이템 수량 편집
    /// var quantityField = new UTKIntegerField("보유 수량", item.Quantity);
+    /// quantityField.ErrorMessage = "수량은 0 이상이어야 합니다.";
+    /// quantityField.Validation = () => quantityField.Value >= 0;
    /// quantityField.OnValueChanged += (newQty) => {
-    ///     item.Quantity = Mathf.Max(0, newQty);  // 음수 방지
+    ///     item.Quantity = newQty;
    ///     UpdateInventoryUI();
    /// };
    /// </code>
@@ -70,6 +99,9 @@ namespace UVC.UIToolkit
        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -85,6 +117,27 @@ namespace UVC.UIToolkit
            set => this.value = value;
        }

+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-integer-field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+
        /// <summary>활성화 상태</summary>
        [UxmlAttribute("is-enabled")]
        public bool IsEnabled
@@ -131,6 +184,8 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<int>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
+            RegisterCallback<KeyDownEvent>(OnKeyDown, TrickleDown.TrickleDown);
        }

        private void SubscribeToThemeChanges()
@@ -163,6 +218,81 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+
+        private void OnKeyDown(KeyDownEvent evt)
+        {
+            if (evt.keyCode == KeyCode.Return)
+            {
+                RunValidation();
+            }
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-integer-field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-integer-field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-integer-field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -174,8 +304,12 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<int>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            UnregisterCallback<KeyDownEvent>(OnKeyDown);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKLongField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKLongField.cs
@@ -17,6 +17,8 @@ namespace UVC.UIToolkit
    ///   <item><description>파일 크기(바이트), 타임스탬프, 고유 ID 등에 사용</description></item>
    ///   <item><description>int 범위(-21억~21억)를 초과하는 값에 적합</description></item>
    ///   <item><description>일반 정수는 UTKIntegerField 사용 권장 (메모리 효율)</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
    /// </list>
    /// </remarks>
    /// <example>
@@ -39,6 +41,26 @@ namespace UVC.UIToolkit
    /// long currentValue = longField.Value;
    /// longField.Value = 5000000000L;  // 50억
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var fileSizeField = new UTKLongField("파일 크기", 0);
+    /// fileSizeField.ErrorMessage = "파일 크기는 0보다 커야 합니다.";
+    /// fileSizeField.Validation = () => fileSizeField.Value > 0;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = fileSizeField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// fileSizeField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// longField.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// longField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 Long 필드 -->
@@ -64,6 +86,9 @@ namespace UVC.UIToolkit
        #region Fields
        private bool _disposed;
        private bool _isEnabled = true;
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -79,6 +104,27 @@ namespace UVC.UIToolkit
            set => this.value = value;
        }

+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-long-field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+
        /// <summary>활성화 상태</summary>
        [UxmlAttribute("is-enabled")]
        public bool IsEnabled
@@ -125,6 +171,8 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<long>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
+            RegisterCallback<KeyDownEvent>(OnKeyDown, TrickleDown.TrickleDown);
        }

        private void SubscribeToThemeChanges()
@@ -157,6 +205,81 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+
+        private void OnKeyDown(KeyDownEvent evt)
+        {
+            if (evt.keyCode == KeyCode.Return)
+            {
+                RunValidation();
+            }
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-long-field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-long-field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-long-field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -168,8 +291,12 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<long>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            UnregisterCallback<KeyDownEvent>(OnKeyDown);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKRectField.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKRectField.cs
@@ -17,6 +17,8 @@ namespace UVC.UIToolkit
    ///   <item><description><b>X, Y</b>: 사각형의 왼쪽 상단 모서리 위치</description></item>
    ///   <item><description><b>Width</b>: 사각형의 너비</description></item>
    ///   <item><description><b>Height</b>: 사각형의 높이</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
    /// </list>
    /// <para>주로 UI 요소의 위치/크기, 스프라이트 영역, 화면 좌표 등에 사용됩니다.</para>
    /// </remarks>
@@ -47,6 +49,26 @@ namespace UVC.UIToolkit
    /// readOnlyField.Value = new Rect(10, 10, 200, 100);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var areaField = new UTKRectField("영역");
+    /// areaField.ErrorMessage = "너비와 높이는 0보다 커야 합니다.";
+    /// areaField.Validation = () => areaField.Value.width > 0 &amp;&amp; areaField.Value.height > 0;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = areaField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// areaField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// areaField.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// areaField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 Rect 필드 -->
@@ -68,6 +90,8 @@ namespace UVC.UIToolkit
    /// // 스프라이트 UV 영역 편집기
    /// var uvField = new UTKRectField("UV 영역");
    /// uvField.Value = sprite.rect;
+    /// uvField.ErrorMessage = "UV 영역은 텍스처 범위를 초과할 수 없습니다.";
+    /// uvField.Validation = () => uvField.Value.xMax &lt;= texture.width &amp;&amp; uvField.Value.yMax &lt;= texture.height;
    /// uvField.OnValueChanged += (newRect) => {
    ///     // 스프라이트 영역 업데이트
    ///     UpdateSpriteRect(sprite, newRect);
@@ -89,6 +113,9 @@ namespace UVC.UIToolkit
        private string _yLabel = "Y";
        private string _wLabel = "W";
        private string _hLabel = "H";
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -117,6 +144,27 @@ namespace UVC.UIToolkit
            set => this.value = value;
        }

+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-rectfield--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
+
        /// <summary>X 라벨</summary>
        [UxmlAttribute("x-label")]
        public string XLabel
@@ -221,6 +269,7 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Rect>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
        }

        private void SubscribeToThemeChanges()
@@ -276,6 +325,73 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-rectfield--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-rectfield--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-rectfield__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -287,8 +403,11 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<Rect>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKVector2Field.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKVector2Field.cs
@@ -16,6 +16,13 @@ namespace UVC.UIToolkit
    /// <para>- X: 수평(가로) 방향의 값</para>
    /// <para>- Y: 수직(세로) 방향의 값</para>
    /// <para>주로 2D 게임의 위치, UI 크기, 텍스처 좌표(UV) 등에 사용됩니다.</para>
+    /// <para><b>주요 기능:</b></para>
+    /// <list type="bullet">
+    ///   <item><description>X, Y 축 라벨 커스터마이징</description></item>
+    ///   <item><description>읽기 전용 모드</description></item>
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
+    /// </list>
    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
@@ -44,6 +51,26 @@ namespace UVC.UIToolkit
    /// readOnlyField.Value = new Vector2(100, 50);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var sizeField = new UTKVector2Field("크기");
+    /// sizeField.ErrorMessage = "크기는 양수여야 합니다.";
+    /// sizeField.Validation = () => sizeField.Value.x > 0 && sizeField.Value.y > 0;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = sizeField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// sizeField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이)
+    /// sizeField.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// sizeField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code>
    /// <!-- 네임스페이스 선언 -->
@@ -59,6 +86,9 @@ namespace UVC.UIToolkit
    ///
    ///     <!-- 읽기 전용 -->
    ///     <utk:UTKVector2Field label="고정 크기" is-readonly="true" />
+    ///
+    ///     <!-- 에러 메시지 (C#에서 Validation 설정 권장) -->
+    ///     <utk:UTKVector2Field label="크기" error-message="크기는 양수여야 합니다." />
    /// </UXML>
    /// </code>
    /// <para><b>실제 활용 예시:</b></para>
@@ -90,6 +120,9 @@ namespace UVC.UIToolkit
        private bool _isReadOnly = false;
        private string _xLabel = "X";
        private string _yLabel = "Y";
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -154,6 +187,27 @@ namespace UVC.UIToolkit
                EnableInClassList("utk-vector2-field--readonly", value);
            }
        }
+
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-vector2-field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
        #endregion

        #region Constructor
@@ -198,6 +252,7 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Vector2>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
        }

        private void SubscribeToThemeChanges()
@@ -251,6 +306,73 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-vector2-field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-vector2-field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-vector2-field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -262,8 +384,12 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<Vector2>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKVector3Field.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKVector3Field.cs
@@ -52,6 +52,26 @@ namespace UVC.UIToolkit
    /// readOnlyField.Value = new Vector3(1, 2, 3);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var posField = new UTKVector3Field("위치");
+    /// posField.ErrorMessage = "Y값은 0 이상이어야 합니다.";
+    /// posField.Validation = () => posField.Value.y >= 0;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = posField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// posField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// posField.ErrorMessage = "유효하지 않은 좌표입니다.";
+    /// posField.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code><![CDATA[
    /// <!-- 기본 Vector3 필드 -->
@@ -66,6 +86,9 @@ namespace UVC.UIToolkit
    ///
    /// <!-- 읽기 전용 -->
    /// <utk:UTKVector3Field label="고정 위치" is-readonly="true" />
+    ///
+    /// <!-- 에러 메시지 (C#에서 Validation 설정 권장) -->
+    /// <utk:UTKVector3Field label="위치" error-message="유효하지 않은 좌표입니다." />
    /// ]]></code>
    /// <para><b>실제 활용 예시 (Transform 편집기):</b></para>
    /// <code>
@@ -97,6 +120,9 @@ namespace UVC.UIToolkit
        private string _xLabel = "X";
        private string _yLabel = "Y";
        private string _zLabel = "Z";
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -173,6 +199,36 @@ namespace UVC.UIToolkit
                EnableInClassList("utk-vector3-field--readonly", value);
            }
        }
+
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-vector3-field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>
+        /// 검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시.
+        /// </summary>
+        /// <example>
+        /// <code>
+        /// var posField = new UTKVector3Field("위치");
+        /// posField.ErrorMessage = "Y값은 0 이상이어야 합니다.";
+        /// posField.Validation = () => posField.Value.y >= 0;
+        /// </code>
+        /// </example>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
        #endregion

        #region Constructor
@@ -217,6 +273,7 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Vector3>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
        }

        private void SubscribeToThemeChanges()
@@ -271,6 +328,73 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-vector3-field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-vector3-field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-vector3-field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -282,8 +406,11 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<Vector3>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/Input/UTKVector4Field.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Input/UTKVector4Field.cs
@@ -18,6 +18,10 @@ namespace UVC.UIToolkit
    /// <para>- 색상(RGBA): Red, Green, Blue, Alpha 값 (0~1 범위)</para>
    /// <para>- 쉐이더 파라미터: 커스텀 쉐이더에 전달하는 4개의 값</para>
    /// <para>- 사원수(Quaternion)와 유사한 구조로 회전 데이터 저장</para>
+    /// <list type="bullet">
+    ///   <item><description>Validation 함수를 통한 입력 검증 (FocusOut 시 자동 호출)</description></item>
+    ///   <item><description>에러 상태 시 붉은 외곽선 + 에러 메시지 표시</description></item>
+    /// </list>
    /// </remarks>
    /// <example>
    /// <para><b>C# 코드에서 사용:</b></para>
@@ -48,6 +52,26 @@ namespace UVC.UIToolkit
    /// readOnlyField.Value = new Vector4(1, 0.5f, 0.5f, 1);
    /// readOnlyField.IsReadOnly = true;
    /// </code>
+    /// <para><b>Validation (입력 검증):</b></para>
+    /// <code>
+    /// // 검증 함수 설정 (Func&lt;bool&gt;)
+    /// var colorField = new UTKVector4Field("색상");
+    /// colorField.ErrorMessage = "알파 값은 0~1 사이여야 합니다.";
+    /// colorField.Validation = () => colorField.Value.w >= 0 &amp;&amp; colorField.Value.w &lt;= 1;
+    /// // → FocusOut 시 자동으로 검증
+    /// // → 실패 시 붉은 외곽선 + 에러 메시지 표시, 통과 시 자동 해제
+    ///
+    /// // 강제 검증 호출 (예: 폼 제출 버튼 클릭 시)
+    /// bool isValid = colorField.Validate();
+    /// if (!isValid) return; // 검증 실패
+    ///
+    /// // 에러 수동 해제
+    /// colorField.ClearError();
+    ///
+    /// // 에러 메시지 직접 설정 (Validation 없이, 서버 오류 등)
+    /// vec4Field.ErrorMessage = "서버 오류가 발생했습니다.";
+    /// vec4Field.ErrorMessage = "";  // 오류 제거
+    /// </code>
    /// <para><b>UXML에서 사용:</b></para>
    /// <code>
    /// <!-- 네임스페이스 선언 -->
@@ -64,6 +88,9 @@ namespace UVC.UIToolkit
    ///
    ///     <!-- 읽기 전용 -->
    ///     <utk:UTKVector4Field label="고정값" is-readonly="true" />
+    ///
+    ///     <!-- 에러 메시지 (C#에서 Validation 설정 권장) -->
+    ///     <utk:UTKVector4Field label="색상" error-message="알파 값은 0~1 사이여야 합니다." />
    /// </UXML>
    /// </code>
    /// <para><b>실제 활용 예시:</b></para>
@@ -95,6 +122,9 @@ namespace UVC.UIToolkit
        private string _yLabel = "Y";
        private string _zLabel = "Z";
        private string _wLabel = "W";
+        private string _errorMessage = "";
+        private Func<bool>? _validation;
+        private Label? _errorLabel;
        #endregion

        #region Events
@@ -183,6 +213,27 @@ namespace UVC.UIToolkit
                EnableInClassList("utk-vector4field--readonly", value);
            }
        }
+
+        /// <summary>에러 메시지. 비어있지 않으면 에러 상태로 표시</summary>
+        [UxmlAttribute("error-message")]
+        public string ErrorMessage
+        {
+            get => _errorMessage;
+            set
+            {
+                _errorMessage = value;
+                var hasError = !string.IsNullOrEmpty(value);
+                EnableInClassList("utk-vector4field--error", hasError);
+                UpdateErrorLabel(hasError ? value : null);
+            }
+        }
+
+        /// <summary>검증 함수. FocusOut 시 호출되어 false 반환 시 ErrorMessage 표시</summary>
+        public Func<bool>? Validation
+        {
+            get => _validation;
+            set => _validation = value;
+        }
        #endregion

        #region Constructor
@@ -227,6 +278,7 @@ namespace UVC.UIToolkit
        private void SetupEvents()
        {
            RegisterCallback<ChangeEvent<Vector4>>(OnFieldValueChanged);
+            RegisterCallback<FocusOutEvent>(OnFocusOut);
        }

        private void SubscribeToThemeChanges()
@@ -282,6 +334,73 @@ namespace UVC.UIToolkit
        {
            OnValueChanged?.Invoke(evt.newValue);
        }
+
+        private void OnFocusOut(FocusOutEvent evt)
+        {
+            RunValidation();
+        }
+        #endregion
+
+        #region Methods
+        /// <summary>
+        /// 강제로 Validation을 실행하여 에러 상태를 업데이트합니다.
+        /// </summary>
+        /// <returns>Validation이 null이면 true, 아니면 Validation 결과</returns>
+        public bool Validate()
+        {
+            return RunValidation();
+        }
+
+        /// <summary>에러 상태를 수동으로 해제합니다.</summary>
+        public void ClearError()
+        {
+            ErrorMessage = "";
+        }
+
+        private bool RunValidation()
+        {
+            if (_validation == null) return true;
+
+            var isValid = _validation.Invoke();
+            if (isValid)
+            {
+                // 검증 통과 시 에러 상태 해제
+                EnableInClassList("utk-vector4field--error", false);
+                UpdateErrorLabel(null);
+            }
+            else
+            {
+                // 검증 실패 시 에러 상태 표시
+                EnableInClassList("utk-vector4field--error", true);
+                UpdateErrorLabel(_errorMessage);
+            }
+            return isValid;
+        }
+
+        private void UpdateErrorLabel(string? message)
+        {
+            if (string.IsNullOrEmpty(message))
+            {
+                // 에러 라벨 숨기기 (존재하면)
+                if (_errorLabel != null)
+                {
+                    _errorLabel.style.display = DisplayStyle.None;
+                }
+                return;
+            }
+
+            // 에러 라벨 생성 (지연 생성 - 필요할 때만)
+            if (_errorLabel == null)
+            {
+                _errorLabel = new Label();
+                _errorLabel.AddToClassList("utk-vector4field__error-message");
+                _errorLabel.style.display = DisplayStyle.None;
+                Add(_errorLabel);
+            }
+
+            _errorLabel.text = message;
+            _errorLabel.style.display = DisplayStyle.Flex;
+        }
        #endregion

        #region IDisposable
@@ -293,8 +412,11 @@ namespace UVC.UIToolkit
            UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
            UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
            UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
-            OnValueChanged = null;
            UnregisterCallback<ChangeEvent<Vector4>>(OnFieldValueChanged);
+            UnregisterCallback<FocusOutEvent>(OnFocusOut);
+            OnValueChanged = null;
+            _validation = null;
+            _errorLabel = null;
        }
        #endregion
    }
--- a/Assets/Scripts/UVC/UIToolkit/List/UTKPropertyList.cs
+++ b/Assets/Scripts/UVC/UIToolkit/List/UTKPropertyList.cs
@@ -976,10 +976,13 @@ namespace UVC.UIToolkit
            // TreeView 갱신은 ToggleGroupExpanded에서 처리
        }

-        private void OnItemValueChanged(IUTKPropertyItem item, object? oldValue, object? newValue)
+        private void OnItemValueChanged(IUTKPropertyItem item, object? oldValue, object? newValue, bool notify)
        {
-            var args = new UTKPropertyValueChangedEventArgs(item, oldValue, newValue);
-            OnPropertyValueChanged?.Invoke(args);
+            if (notify)
+            {
+                var args = new UTKPropertyValueChangedEventArgs(item, oldValue, newValue);
+                OnPropertyValueChanged?.Invoke(args);
+            }
        }

        private void OnSearch(string newValue)
--- a/Assets/Scripts/UVC/UIToolkit/Property/Core/IUTKPropertyItem.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Property/Core/IUTKPropertyItem.cs
@@ -38,7 +38,7 @@ namespace UVC.UIToolkit
        string? GroupId { get; set; }

        /// <summary>값 변경 이벤트</summary>
-        event Action<IUTKPropertyItem, object?, object?>? OnValueChanged;
+        event Action<IUTKPropertyItem, object?, object?, bool>? OnValueChanged;

        /// <summary>상태(ReadOnly 등) 변경 이벤트. View가 구독하여 UI를 갱신합니다.</summary>
        event Action<IUTKPropertyItem>? OnStateChanged;
--- a/Assets/Scripts/UVC/UIToolkit/Property/Items/Base/UTKPropertyItemBase.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Property/Items/Base/UTKPropertyItemBase.cs
@@ -124,7 +124,7 @@ namespace UVC.UIToolkit

        #region Events
        /// <summary>값 변경 이벤트 (object 타입)</summary>
-        public event Action<IUTKPropertyItem, object?, object?>? OnValueChanged;
+        public event Action<IUTKPropertyItem, object?, object?, bool>? OnValueChanged;

        /// <summary>값 변경 이벤트 (제네릭 타입)</summary>
        public event Action<IUTKPropertyItem<T>, T, T>? OnTypedValueChanged;
@@ -159,35 +159,34 @@ namespace UVC.UIToolkit
            {
                if (default(T) == null)
                {
-                    if (notifyChangeEvent)
-                    {
-                        Value = default!;
-                    }
-                    else
+                    if (!Equals(_value, value))
                    {
+                        var oldValue = _value;
                        _value = default!;
+                        NotifyValueChanged(oldValue, default!, notifyChangeEvent);
                    }
                }
            }
            else if (value is T typedValue)
            {
-                if (notifyChangeEvent)
-                {
-                    Value = typedValue;
-                }
-                else
+                if (!Equals(_value, typedValue))
                {
+                    var oldValue = _value;
                    _value = typedValue;
+                    NotifyValueChanged(oldValue, typedValue, notifyChangeEvent);
                }
            }
            else
            {
                try
                {
-                    if (notifyChangeEvent)
-                        Value = (T)Convert.ChangeType(value, typeof(T));
-                    else
-                        _value = (T)Convert.ChangeType(value, typeof(T));
+                    var  v = (T)Convert.ChangeType(value, typeof(T));
+                    if (!Equals(_value, v))
+                    {
+                        var oldValue = _value;
+                        _value = v;
+                        NotifyValueChanged(oldValue, v, notifyChangeEvent);
+                    }
                }
                catch (Exception ex)
                {
@@ -199,10 +198,10 @@ namespace UVC.UIToolkit

        #region Protected Methods
        /// <summary>값 변경을 알립니다.</summary>
-        protected void NotifyValueChanged(T oldValue, T newValue)
+        protected void NotifyValueChanged(T oldValue, T newValue, bool notifyChangeEvent = false)
        {
            OnTypedValueChanged?.Invoke(this, oldValue, newValue);
-            OnValueChanged?.Invoke(this, oldValue, newValue);
+            OnValueChanged?.Invoke(this, oldValue, newValue, notifyChangeEvent);
        }
        #endregion

--- a/Assets/Scripts/UVC/UIToolkit/Property/Views/UTKFloatDropdownPropertyItemView.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Property/Views/UTKFloatDropdownPropertyItemView.cs
@@ -14,7 +14,7 @@ namespace UVC.UIToolkit
    /// <para><b>사용법 (Data 바인딩):</b></para>
    /// <code>
    /// var data = new UTKFloatDropdownPropertyItem("id", "Label", 1.5f,
-    ///     new List&lt;string&gt; { "A", "B", "C" }, "A");
+    ///     new List<string> { "A", "B", "C" }, "A");
    /// var view = new UTKFloatDropdownPropertyItemView();
    /// view.Bind(data);
    /// </code>
--- a/Assets/Scripts/UVC/UIToolkit/UTKThemeManager.cs
+++ b/Assets/Scripts/UVC/UIToolkit/UTKThemeManager.cs
@@ -128,8 +128,8 @@ namespace UVC.UIToolkit
    ///     private void SubscribeToThemeChanges()
    ///     {
    ///         UTKThemeManager.Instance.OnThemeChanged += OnThemeChanged;
-    ///         RegisterCallback&lt;AttachToPanelEvent&gt;(OnAttachToPanelForTheme);
-    ///         RegisterCallback&lt;DetachFromPanelEvent&gt;(OnDetachFromPanelForTheme);
+    ///         RegisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
+    ///         RegisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
    ///     }
    ///
    ///     private void OnAttachToPanelForTheme(AttachToPanelEvent evt)
@@ -154,8 +154,8 @@ namespace UVC.UIToolkit
    ///         if (_disposed) return;
    ///         _disposed = true;
    ///         UTKThemeManager.Instance.OnThemeChanged -= OnThemeChanged;
-    ///         UnregisterCallback&lt;AttachToPanelEvent&gt;(OnAttachToPanelForTheme);
-    ///         UnregisterCallback&lt;DetachFromPanelEvent&gt;(OnDetachFromPanelForTheme);
+    ///         UnregisterCallback<AttachToPanelEvent>(OnAttachToPanelForTheme);
+    ///         UnregisterCallback<DetachFromPanelEvent>(OnDetachFromPanelForTheme);
    ///     }
    /// }
    /// </code>
--- a/Assets/Scripts/UVC/UIToolkit/Window/UTKPropertyListWindow.cs
+++ b/Assets/Scripts/UVC/UIToolkit/Window/UTKPropertyListWindow.cs
@@ -51,7 +51,7 @@ namespace UVC.UIToolkit
    /// };
    ///
    /// // 3. 데이터 로드 (그룹 + 개별 아이템 혼합)
-    /// var entries = new List&lt;IUTKPropertyEntry&gt;();
+    /// var entries = new List<IUTKPropertyEntry>();
    /// entries.Add(new UTKStringPropertyItem("name", "이름", "기본값"));
    ///
    /// var group = new UTKPropertyGroup("transform", "Transform");