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/components/CodeSnippet/index.svelte

@@ -1,9 +1,9 @@
 <script>
-  import marked from "marked";
+  import marked from 'marked';
 
-  export let code = "";
+  export let code = '';
 </script>
 
-<div class="bg-gray-200 p-5 rounded-md mb-3">
-  {@html marked("```js\n" + code + "\n```")}
+<div class="bg-gray-200 dark:bg-gray-500 p-5 rounded-md mb-3">
+  {@html marked('```js\n' + code + '\n```')}
 </div>