remove outdated stylesheet

Author: jgerigmeyer

index.html

@@ -10,11 +10,6 @@
       rel="stylesheet"
       href="https://unpkg.com/[email protected]/themes/prism.css"
     />
-    <link
-      rel="stylesheet"
-      href="https://unpkg.com/@oddbird/popover-polyfill@latest/dist/popover.css"
-      crossorigin="anonymous"
-    />
     <script
       src="https://unpkg.com/@oddbird/popover-polyfill@latest/dist/popover.min.js"
       crossorigin="anonymous"