diff --git a/ui/src/routes/api/settings/+server.ts b/ui/src/routes/api/settings/+server.ts
index d2fe4f8..0c69366 100644
--- a/ui/src/routes/api/settings/+server.ts
+++ b/ui/src/routes/api/settings/+server.ts
@@ -45,7 +45,7 @@ export const PUT: RequestHandler = async ({ request, locals }) => {
 	}
 
 	// theme is optional — if provided (and non-empty) it must be a known value
-	const validThemes = ['amber', 'slate', 'rose', 'light', 'light-slate', 'light-rose'];
+	const validThemes = ['amber', 'slate', 'rose', 'forest', 'mono', 'cyber', 'light', 'light-slate', 'light-rose'];
 	if (body.theme !== undefined && body.theme !== '' && !validThemes.includes(body.theme)) {
 		error(400, `Invalid theme — must be one of: ${validThemes.join(', ')}`);
 	}