diff --git a/sites/svelte.dev/src/app.html b/sites/svelte.dev/src/app.html
index ba38bf1692..99ce1df112 100644
--- a/sites/svelte.dev/src/app.html
+++ b/sites/svelte.dev/src/app.html
@@ -30,6 +30,16 @@
 		%sveltekit.head%
 	</head>
 	<body data-sveltekit-preload-code="hover">
+		<script>
+			const themeValue = JSON.parse(localStorage.getItem('svelte:theme'))?.current;
+			const systemPreferredTheme = window.matchMedia('(prefers-color-scheme: dark)').matches
+				? 'dark'
+				: 'light';
+
+			document.body.classList.remove('light', 'dark');
+			document.body.classList.add(themeValue ?? systemPreferredTheme);
+		</script>
+
 		<div style="height: 100%">%sveltekit.body%</div>
 	</body>
 </html>
