feat: support changes in system theme (#484)

* feat: support changes in system theme

* fix: run prettier

* fix: add content/.gitkeep

quartz/components/scripts/darkmode.inline.ts

@@ -20,4 +20,13 @@ document.addEventListener("nav", () => {
   if (currentTheme === "dark") {
     toggleSwitch.checked = true
   }
+
+  // Listen for changes in prefers-color-scheme
+  const colorSchemeMediaQuery = window.matchMedia("(prefers-color-scheme: dark)")
+  colorSchemeMediaQuery.addEventListener("change", (e) => {
+    const newTheme = e.matches ? "dark" : "light"
+    document.documentElement.setAttribute("saved-theme", newTheme)
+    localStorage.setItem("theme", newTheme)
+    toggleSwitch.checked = e.matches
+  })
 })