CLASSROOMIO-T-41: Implement dark/light mode switch

Co-authored-by: Rotimi Best <rotimiibitoyeemma@gmail.com>

Merge-request: CLASSROOMIO-MR-8
Merged-by: Digdippa Team <digdippa@gmail.com>

src/routes/org/[slug]/settings/domains.svelte

@@ -10,11 +10,11 @@
 <section class="w-full max-w-6xl mx-auto">
   <div class="py-10 px-5">
     <a
-      class="text-gray-500 text-md"
+      class="text-gray-500 dark:text-gray-200 text-md"
       href={`/org/${$currentOrg.siteName}/settings`}>Back to Settings</a
     >
     <div class="flex items-center justify-between mb-10">
-      <h1 class="text-3xl font-bold">Custom domain</h1>
+      <h1 class="dark:text-white text-3xl font-bold">Custom domain</h1>
     </div>
 
     <Domains />