Improve background image visibility fix using background-blend-mode

Co-authored-by: ulysses4ever <[email protected]>

Author: Copilot

docs/assets/css/dark-mode.css

@@ -8,8 +8,9 @@ body.dark-mode {
 
 body.dark-mode.introcontent {
     background-color: #2d2d2d;
-    /* Keep the background image visible in dark mode with reduced opacity */
-    opacity: 0.95;
+    /* Keep the background image visible but dimmed for dark mode */
+    background-blend-mode: darken;
+    background-color: rgba(45, 45, 45, 0.7);
 }
 
 body.dark-mode .bgwrapper {