fix dropdown issue, add autoprefix for scss

main.js

@@ -1,4 +1,4 @@
-import './css/ui.min.css'
+import './css/ui.scss'
 import './style.css'
 // import javascriptLogo from './javascript.svg'
 import { get } from './lib/utility'
@@ -26,7 +26,7 @@ function navigate(page) {
 }
 
 document.querySelector('#directory').addEventListener('click', ev => {
-    const page = ev.target.getAttribute('data-page');
+    const page = ev.target.dataset.page;
     if (typeof page === 'string') {
         location.hash = page;
         navigate(page);