diff --git a/admin/css/admin-styles.css b/admin/css/admin-styles.css
index 040509b..b5bac39 100644
--- a/admin/css/admin-styles.css
+++ b/admin/css/admin-styles.css
@@ -6,140 +6,140 @@
 
 /* General Admin Styles */
 .wpst-admin-page {
-	max-width: 1200px;
-	margin: 20px auto;
-	padding: 20px;
-	background: #fff;
-	border-radius: 5px;
-	box-shadow: 0 1px 3px rgb(0 0 0 / 10%);
+    max-width: 1200px;
+    margin: 20px auto;
+    padding: 20px;
+    background: #fff;
+    border-radius: 5px;
+    box-shadow: 0 1px 3px rgb(0 0 0 / 10%);
 }
 
 .wpst-admin-header {
-	margin-bottom: 20px;
-	padding-bottom: 20px;
-	border-bottom: 1px solid #eee;
+    margin-bottom: 20px;
+    padding-bottom: 20px;
+    border-bottom: 1px solid #eee;
 }
 
 .wpst-admin-header h1 {
-	margin-top: 0;
-	color: #23282d;
+    margin-top: 0;
+    color: #23282d;
 }
 
 /* Admin Form Styles */
 .wpst-form-table {
-	width: 100%;
-	border-collapse: collapse;
+    width: 100%;
+    border-collapse: collapse;
 }
 
 .wpst-form-table th {
-	text-align: left;
-	padding: 15px 10px 15px 0;
-	width: 200px;
-	vertical-align: top;
+    text-align: left;
+    padding: 15px 10px 15px 0;
+    width: 200px;
+    vertical-align: top;
 }
 
 .wpst-form-table td {
-	padding: 15px 0;
-	vertical-align: middle;
+    padding: 15px 0;
+    vertical-align: middle;
 }
 
 .wpst-form-table input[type="text"],
 .wpst-form-table input[type="number"],
 .wpst-form-table select,
 .wpst-form-table textarea {
-	width: 400px;
-	max-width: 100%;
+    width: 400px;
+    max-width: 100%;
 }
 
 .wpst-form-table textarea {
-	min-height: 100px;
+    min-height: 100px;
 }
 
 .wpst-form-description {
-	color: #666;
-	font-style: italic;
-	margin-top: 5px;
+    color: #666;
+    font-style: italic;
+    margin-top: 5px;
 }
 
 /* Admin Notices */
 .wpst-notice {
-	padding: 10px 15px;
-	margin: 15px 0;
-	border-radius: 3px;
-	border-left: 4px solid #00a0d2;
-	background: #f7fcff;
+    padding: 10px 15px;
+    margin: 15px 0;
+    border-radius: 3px;
+    border-left: 4px solid #00a0d2;
+    background: #f7fcff;
 }
 
 .wpst-notice.success {
-	border-left-color: #46b450;
-	background: #ecf7ed;
+    border-left-color: #46b450;
+    background: #ecf7ed;
 }
 
 .wpst-notice.error {
-	border-left-color: #dc3232;
-	background: #fbeaea;
+    border-left-color: #dc3232;
+    background: #fbeaea;
 }
 
 .wpst-notice.warning {
-	border-left-color: #ffb900;
-	background: #fff8e5;
+    border-left-color: #ffb900;
+    background: #fff8e5;
 }
 
 /* Admin Cards */
 .wpst-card-container {
-	display: flex;
-	flex-wrap: wrap;
-	margin: 0 -10px;
+    display: flex;
+    flex-wrap: wrap;
+    margin: 0 -10px;
 }
 
 .wpst-card {
-	flex: 1 0 300px;
-	margin: 10px;
-	padding: 20px;
-	background: #fff;
-	border-radius: 3px;
-	box-shadow: 0 1px 3px rgb(0 0 0 / 10%);
+    flex: 1 0 300px;
+    margin: 10px;
+    padding: 20px;
+    background: #fff;
+    border-radius: 3px;
+    box-shadow: 0 1px 3px rgb(0 0 0 / 10%);
 }
 
 .wpst-card-header {
-	margin-bottom: 15px;
-	padding-bottom: 15px;
-	border-bottom: 1px solid #eee;
+    margin-bottom: 15px;
+    padding-bottom: 15px;
+    border-bottom: 1px solid #eee;
 }
 
 .wpst-card-title {
-	margin: 0;
-	font-size: 16px;
-	font-weight: 600;
+    margin: 0;
+    font-size: 16px;
+    font-weight: 600;
 }
 
 .wpst-card-content {
-	margin-bottom: 15px;
+    margin-bottom: 15px;
 }
 
 .wpst-card-footer {
-	padding-top: 15px;
-	border-top: 1px solid #eee;
-	text-align: right;
+    padding-top: 15px;
+    border-top: 1px solid #eee;
+    text-align: right;
 }
 
 /* Responsive Styles */
 @media screen and (width <= 782px) {
-	.wpst-form-table th {
-		width: 100%;
-		display: block;
-		padding-bottom: 0;
-	}
+    .wpst-form-table th {
+        width: 100%;
+        display: block;
+        padding-bottom: 0;
+    }
 
-	.wpst-form-table td {
-		width: 100%;
-		display: block;
-	}
+    .wpst-form-table td {
+        width: 100%;
+        display: block;
+    }
 
-	.wpst-form-table input[type="text"],
-	.wpst-form-table input[type="number"],
-	.wpst-form-table select,
-	.wpst-form-table textarea {
-		width: 100%;
-	}
+    .wpst-form-table input[type="text"],
+    .wpst-form-table input[type="number"],
+    .wpst-form-table select,
+    .wpst-form-table textarea {
+        width: 100%;
+    }
 }
diff --git a/admin/css/update-source-selector.css b/admin/css/update-source-selector.css
index 3f8b91e..35cca99 100644
--- a/admin/css/update-source-selector.css
+++ b/admin/css/update-source-selector.css
@@ -6,138 +6,138 @@
 
 /* Modal Styles */
 .wpst-modal {
-	display: none;
-	position: fixed;
-	z-index: 100000;
-	left: 0;
-	top: 0;
-	width: 100%;
-	height: 100%;
-	overflow: auto;
-	background-color: rgb(0 0 0 / 40%);
+    display: none;
+    position: fixed;
+    z-index: 100000;
+    left: 0;
+    top: 0;
+    width: 100%;
+    height: 100%;
+    overflow: auto;
+    background-color: rgb(0 0 0 / 40%);
 }
 
 .wpst-modal-content {
-	position: relative;
-	background-color: #fefefe;
-	margin: 10% auto;
-	padding: 20px;
-	border-radius: 5px;
-	box-shadow: 0 4px 8px rgb(0 0 0 / 10%);
-	width: 500px;
-	max-width: 90%;
+    position: relative;
+    background-color: #fefefe;
+    margin: 10% auto;
+    padding: 20px;
+    border-radius: 5px;
+    box-shadow: 0 4px 8px rgb(0 0 0 / 10%);
+    width: 500px;
+    max-width: 90%;
 }
 
 .wpst-modal-header {
-	padding-bottom: 15px;
-	border-bottom: 1px solid #eee;
-	margin-bottom: 15px;
+    padding-bottom: 15px;
+    border-bottom: 1px solid #eee;
+    margin-bottom: 15px;
 }
 
 .wpst-modal-title {
-	margin: 0;
-	font-size: 18px;
-	font-weight: 600;
+    margin: 0;
+    font-size: 18px;
+    font-weight: 600;
 }
 
 .wpst-modal-close {
-	position: absolute;
-	top: 10px;
-	right: 15px;
-	font-size: 20px;
-	font-weight: 700;
-	color: #666;
-	cursor: pointer;
+    position: absolute;
+    top: 10px;
+    right: 15px;
+    font-size: 20px;
+    font-weight: 700;
+    color: #666;
+    cursor: pointer;
 }
 
 .wpst-modal-close:hover,
 .wpst-modal-close:focus {
-	color: #000;
-	text-decoration: none;
+    color: #000;
+    text-decoration: none;
 }
 
 .wpst-modal-body {
-	margin-bottom: 20px;
+    margin-bottom: 20px;
 }
 
 .wpst-modal-footer {
-	padding-top: 15px;
-	border-top: 1px solid #eee;
-	text-align: right;
+    padding-top: 15px;
+    border-top: 1px solid #eee;
+    text-align: right;
 }
 
 /* Source Selection Styles */
 .wpst-source-options {
-	margin: 15px 0;
+    margin: 15px 0;
 }
 
 .wpst-source-option {
-	display: block;
-	margin-bottom: 10px;
-	padding: 10px;
-	border: 1px solid #ddd;
-	border-radius: 3px;
-	cursor: pointer;
+    display: block;
+    margin-bottom: 10px;
+    padding: 10px;
+    border: 1px solid #ddd;
+    border-radius: 3px;
+    cursor: pointer;
 }
 
 .wpst-source-option:hover {
-	background-color: #f9f9f9;
+    background-color: #f9f9f9;
 }
 
 .wpst-source-option.selected {
-	border-color: #0073aa;
-	background-color: #f0f6fc;
+    border-color: #0073aa;
+    background-color: #f0f6fc;
 }
 
 .wpst-source-option input[type="radio"] {
-	margin-right: 10px;
+    margin-right: 10px;
 }
 
 .wpst-source-option-label {
-	font-weight: 600;
+    font-weight: 600;
 }
 
 .wpst-source-option-description {
-	margin-top: 5px;
-	color: #666;
-	font-size: 13px;
+    margin-top: 5px;
+    color: #666;
+    font-size: 13px;
 }
 
 /* Loading Indicator */
 .wpst-loading {
-	display: inline-block;
-	width: 20px;
-	height: 20px;
-	border: 2px solid rgb(0 0 0 / 10%);
-	border-radius: 50%;
-	border-top-color: #0073aa;
-	animation: wpst-spin 1s ease-in-out infinite;
-	margin-right: 10px;
-	vertical-align: middle;
+    display: inline-block;
+    width: 20px;
+    height: 20px;
+    border: 2px solid rgb(0 0 0 / 10%);
+    border-radius: 50%;
+    border-top-color: #0073aa;
+    animation: wpst-spin 1s ease-in-out infinite;
+    margin-right: 10px;
+    vertical-align: middle;
 }
 
 @keyframes wpst-spin {
-	to {
-		transform: rotate(360deg);
-	}
+    to {
+        transform: rotate(360deg);
+    }
 }
 
 /* Message Styles */
 .wpst-modal-message {
-	padding: 10px;
-	margin: 10px 0;
-	border-radius: 3px;
-	display: none;
+    padding: 10px;
+    margin: 10px 0;
+    border-radius: 3px;
+    display: none;
 }
 
 .wpst-modal-message.success {
-	background-color: #ecf7ed;
-	border: 1px solid #46b450;
-	color: #2a6f31;
+    background-color: #ecf7ed;
+    border: 1px solid #46b450;
+    color: #2a6f31;
 }
 
 .wpst-modal-message.error {
-	background-color: #fbeaea;
-	border: 1px solid #dc3232;
-	color: #8a1f1f;
+    background-color: #fbeaea;
+    border: 1px solid #dc3232;
+    color: #8a1f1f;
 }
diff --git a/package.json b/package.json
index 07c980b..c934d13 100644
--- a/package.json
+++ b/package.json
@@ -29,6 +29,7 @@
     "test:phpunit:multisite": "WP_MULTISITE=1 composer test",
     "build": "./build.sh",
     "lint:js": "eslint cypress/",
+    "lint:css": "stylelint \"**/*.css\" --allow-empty-input",
     "lint:php": "composer run-script phpcs",
     "lint:php:simple": "composer run-script phpcs:simple",
     "lint:phpstan": "composer run-script phpstan",
@@ -38,7 +39,7 @@
     "test:php": "composer run-script test",
     "lint": "composer run-script lint",
     "fix": "composer run-script fix",
-    "quality": "npm run lint && npm run test:php"
+    "quality": "npm run lint && npm run lint:css && npm run test:php"
   },
   "repository": {
     "type": "git",
@@ -64,6 +65,8 @@
     "@wp-playground/cli": "^3.0.22",
     "cypress": "^13.17.0",
     "eslint": "^8.57.0",
-    "eslint-plugin-cypress": "^2.15.1"
+    "eslint-plugin-cypress": "^2.15.1",
+    "stylelint": "^16.0.0",
+    "stylelint-config-standard": "^36.0.0"
   }
 }