change remark42 theme based on browser theme

_includes/comments/remark42.html

@@ -1,26 +1,32 @@
 <script>
     var remark_config = {
-      host: "https://remark42.kottedi.in",
-      site_id: 'remark',
-      secret: 'abcdefgh@4356',
-      components: ['embed'],
-                  
-      max_shown_comments: 10, 
-      theme: 'light', 
-      
-      locale: 'en', 
-      show_email_subscription: false 
+        host: "https://remark42.kottedi.in",
+        site_id: 'remark',
+        secret: 'abcdefgh@4356',
+        components: ['embed'],
+
+        max_shown_comments: 10,
+        theme: 'light',
+
+        locale: 'en',
+        show_email_subscription: false
     };
-  </script>
-  <script>
-    (function(c) {
-      for(var i = 0; i < c.length; i++){
-        var d = document, s = d.createElement('script');
-        s.src = remark_config.host + '/web/' +c[i] +'.js';
-        s.defer = true;
-        (d.head || d.body).appendChild(s);
-      }
+</script>
+<script>
+    (function (c) {
+        for (var i = 0; i < c.length; i++) {
+            var d = document, s = d.createElement('script');
+            s.src = remark_config.host + '/web/' + c[i] + '.js';
+            s.defer = true;
+            (d.head || d.body).appendChild(s);
+        }
     })(remark_config.components || ['embed']);
-  </script>
+
+    window.onload = function () {
+        if (window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches) {
+            window.REMARK42.changeTheme('dark');
+        }
+    }
+</script>
 
 <div id="remark42"></div>