Redo landing page

docs/javascripts/extra.js

@@ -0,0 +1,23 @@
+function copyToClipboardNux() {
+  const text = document.getElementById("ghcup-command-linux").innerText;
+  const el = document.createElement('textarea');
+  el.value = text;
+  document.body.appendChild(el);
+  el.select();
+  document.execCommand('copy');
+  document.body.removeChild(el);
+  const button = document.getElementById("ghcup-linux-button");
+  button.focus();
+}
+
+function copyToClipboardWin() {
+  const text = document.getElementById("ghcup-command-windows").innerText;
+  const el = document.createElement('textarea');
+  el.value = text;
+  document.body.appendChild(el);
+  el.select();
+  document.execCommand('copy');
+  document.body.removeChild(el);
+  const button = document.getElementById("ghcup-windows-button");
+  button.focus();
+}