detect dark theme via css variable

Author: Theta-Dev

web_src/js/utils.js

@@ -26,13 +26,9 @@ export function isObject(obj) {
 
 // returns whether a dark theme is enabled
 export function isDarkTheme() {
-  if (document.documentElement.classList.contains('theme-auto')) {
-    return window.matchMedia('(prefers-color-scheme: dark)').matches;
-  }
-  if (document.documentElement.classList.contains('theme-arc-green')) {
-    return true;
-  }
-  return false;
+  const isDarkTheme = window.getComputedStyle(document.documentElement)
+    .getPropertyValue('--is-dark-theme').trim().toLowerCase();
+  return isDarkTheme === 'true';
 }
 
 // removes duplicate elements in an array

web_src/less/themes/theme-arc-green.less

@@ -1,6 +1,7 @@
 @import "../chroma/dark.less";
 
 :root {
+  --is-dark-theme: true;
   --color-primary: #87ab63;
   --color-primary-dark-1: #93b373;
   --color-primary-dark-2: #9fbc82;