Fix color scheme update on theme toggle

Author: ReneWerner87

no-flash-color-mode-plugin.js

@@ -31,6 +31,20 @@ export default function noFlashColorModePlugin(context) {
     document.documentElement.setAttribute('data-theme', theme);
     document.documentElement.setAttribute('data-theme-choice', storedTheme || (respectPrefersColorScheme ? 'system' : defaultMode));
     document.documentElement.style.colorScheme = theme;
+
+    var observer = new MutationObserver(function(mutationsList) {
+      for (var i = 0; i < mutationsList.length; i++) {
+        var mutation = mutationsList[i];
+        if (mutation.type === 'attributes' && mutation.attributeName === 'data-theme') {
+          var newTheme = document.documentElement.getAttribute('data-theme');
+          if (newTheme) {
+            document.documentElement.style.colorScheme = newTheme;
+          }
+        }
+      }
+    });
+
+    observer.observe(document.documentElement, { attributes: true, attributeFilter: ['data-theme'] });
   })();`,
           },
         ],