Copy paste works.

src/components/hero.astro

@@ -42,7 +42,7 @@ import Navbar from "./navbar.astro";
       </a>
       <a
         class="relative group inline-flex justify-center items-center gap-x-3.5 text-center bg-white border hover:border-gray-300 shadow-sm font-mono text-sm font-medium rounded-md focus:outline-none focus:ring-2 focus:ring-gray-400 focus:ring-offset-2 focus:ring-offset-white transition p-2 pl-4 dark:bg-slate-900 dark:border-stone-950 dark:hover:border-gray-600 dark:shadow-slate-700/[.7] dark:text-white dark:focus:ring-stone-700 dark:focus:ring-offset-stone-950"
-        href="javascript:;"
+        href="javascript:navigator.clipboard.writeText('c3c compile hello.c3');"
       >
         $ c3c compile hello.c3
         <span