add gh-star button, adjust mobile breakpoint

Author: samipe

public/index.html

@@ -39,5 +39,6 @@
     </noscript>
     <div id="app"></div>
     <!-- built files will be auto injected -->
+    <script defer src="/stars-tag.js"></script>
   </body>
 </html>

public/stars-tag.js

@@ -69,7 +69,7 @@ body:not(.accessible) * {
     }
 }
 
-@media screen and (max-width: 428px) {
+@media screen and (max-width: 470px) {
     html, body {
         font-size: var(--size-base-sm);
     }