diff --git a/static/light-toggle.js b/static/light-toggle.js
index 06260d3..429736c 100644
--- a/static/light-toggle.js
+++ b/static/light-toggle.js
@@ -1,5 +1,12 @@
 function themeToggle() {
-  const oldValue = localStorage.getItem('theme');
+  let oldValue = localStorage.getItem('theme');
+  if (!oldValue) {
+    oldValue = 'light';
+    if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
+      oldValue = 'dark';
+    }
+  }
+
   let newValue;
   if (oldValue == 'light') {
     newValue = 'dark';
@@ -15,11 +22,7 @@ function themeClear() {
   themeRefresh();
 }
 
-function themeRefresh(newValue) {
-  if (newValue !== undefined) {
-    localStorage.setItem('theme', newValue);
-  }
-
+function themeRefresh() {
   const theme = localStorage.getItem('theme')
   const el = document.getElementsByTagName('html')[0];
   if (theme == 'light') {