assets: scss: Mark with a softer tone of yellow.

This allows marking to look good on both light and dark themes.

Signed-off-by: Diab Neiroukh <[email protected]>

Author: lzlrd

assets/scss/pages/post.scss

@@ -284,3 +284,7 @@ main {
     color: #f44336;
   }
 }
+
+mark {
+  background-color: #ffee58;
+}