diff --git a/darkerfx/styles/toggle-theme.js b/darkerfx/styles/toggle-theme.js
index 0427b77..32bf512 100644
--- a/darkerfx/styles/toggle-theme.js
+++ b/darkerfx/styles/toggle-theme.js
@@ -1,7 +1,17 @@
 const sw = document.getElementById("switch-style"), b = document.body;
 
 if (sw && b) {
-    sw.checked = window.localStorage && localStorage.getItem("theme") === "theme-dark" || !window.localStorage;
+    if (window.localStorage && localStorage.getItem("theme") === "theme-dark") {
+        // Browser supports local storage and dark mode is configured.
+        sw.checked = true;
+    }
+    else {
+        // Browser does not support local storage, or no stored theme setting is
+        // present. Determine dark mode based on browser settings. Browsers
+        // which don't support media matching will default to light theme, in
+        // line with what most people would expect from a web page.
+        sw.checked = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;
+    }
 
     b.classList.toggle("theme-dark", sw.checked)
     b.classList.toggle("theme-light", !sw.checked)