Add initial theme assets, layouts, and configuration for Hugo site

themes/typo/static/js/theme-switch.js

@@ -0,0 +1,28 @@
+function isAuto() {
+  return document.body.classList.contains("auto");
+}
+
+function setTheme() {
+  if (!isAuto()) {
+    return
+  }
+
+  document.body.classList.remove("auto");
+  let cls = "light";
+  if (window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches) {
+    cls = "dark";
+  }
+
+  document.body.classList.add(cls);
+}
+
+function invertBody() {
+  document.body.classList.toggle("dark");
+  document.body.classList.toggle("light");
+}
+
+if (isAuto()) {
+  window.matchMedia('(prefers-color-scheme: dark)').addListener(invertBody);
+}
+
+setTheme();