sticky download button so long previews doesn't push buttons down, closes #205

components/previews/MarkdownPreview.tsx

@@ -81,7 +81,7 @@ const MarkdownPreview: FunctionComponent<{ file: any; path: string; standalone?:
   }
 
   return (
-    <>
+    <div>
       <div
         className={
           standalone
@@ -99,11 +99,11 @@ const MarkdownPreview: FunctionComponent<{ file: any; path: string; standalone?:
         </ReactMarkdown>
       </div>
       {standalone && (
-        <div className="mt-4">
+        <div className="border-t-gray-200 dark:border-t-gray-700 border-t p-2 sticky bottom-0 left-0 right-0 z-10 bg-white bg-opacity-80 backdrop-blur-md dark:bg-gray-900">
           <DownloadButtonGroup downloadUrl={file['@microsoft.graph.downloadUrl']} />
         </div>
       )}
-    </>
+    </div>
   )
 }