feat: Update contents

contents/validation-icon.mdx

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+---
+category: Feedback
+created: '2019-12-12'
+description: Add validation icons to input with CSS
+keywords: css validation icon
+thumbnail: /assets/css-layout/thumbnails/validation-icon.png
+title: Validation icon
+---
+
+## HTML
+
+```html
+<div class="validation-icon">
+    <!-- The input -->
+    <input class="validation-icon__input" />
+
+    <!-- The icon validation-icon -->
+    <span class="validation-icon__icon">
+        <!-- The SVG icon represents any state such as valid, invalid, loading, etc. -->
+        ...
+    </span>
+</div>
+```
+
+## CSS
+
+```css
+.validation-icon {
+    /* Used to position the validation icon */
+    position: relative;
+}
+
+.validation-icon__input {
+    /* Border */
+    border: 1px solid #d1d5db;
+    border-radius: 0.25rem;
+
+    /* Take the full width */
+    width: 100%;
+    height: 2rem;
+
+    /* Don't overlap the icon */
+    padding-right: 1.5rem;
+}
+
+.validation-icon__icon {
+    /* Positioned at the right side */
+    position: absolute;
+    right: 0.5rem;
+    top: 50%;
+    transform: translate(0, -50%);
+
+    z-index: 10;
+}
+```
+
+<Playground>
+```css styles.css hidden
+body {
+    align-items: center;
+    display: flex;
+    justify-content: center;
+}
+
+.validation-icon {
+    /* Used to position the validation icon */
+    position: relative;
+
+    /* Demo */
+    width: 16rem;
+}
+
+.validation-icon__input {
+    /* Border */
+    border: 1px solid #d1d5db;
+    border-radius: 0.25rem;
+
+    /* Take the full width */
+    width: 100%;
+    height: 2rem;
+
+    /* Don't overlap the icon */
+    padding-right: 1.5rem;
+}
+
+.validation-icon__icon {
+    /* Positioned at the right side */
+    position: absolute;
+    right: 0.5rem;
+    top: 50%;
+    transform: translate(0, -50%);
+
+    z-index: 10;
+}
+
+.validation-icon__svg {
+    fill: none;
+    height: 1rem;
+    width: 1rem;
+    stroke: #22c55e;
+    stroke-linecap: round;
+    stroke-linejoin: round;
+    stroke-width: 2;
+}
+```
+
+```html index.html hidden
+<div class="validation-icon">
+    <input class="validation-icon__input" />
+    <span class="validation-icon__icon">
+        <svg class="validation-icon__svg" viewBox="0 0 24 24">
+            <path d="M23.5,0.499l-16.5,23l-6.5-6.5"></path>
+        </svg>
+    </span>
+</div>
+```
+</Playground>