fix: make dialog backdrop visible by removing :where() wrapper

The :where() pseudo-class gave the backdrop selector zero specificity, causing the browser's UA default to win. Also increase opacity from 0.5 to 0.8 for better contrast.

Author: Leftium

specs/nimble-css.md

@@ -807,8 +807,8 @@ nimble.css does **not** reduce image opacity in dark mode (simple.css does this
   max-width: min(90vw, 40rem);
   padding: var(--nc-spacing);
 }
-:where(dialog::backdrop) {
-  background: rgb(0 0 0 / 0.5);
+dialog::backdrop {
+  background: rgb(0 0 0 / 0.8);
 }
 ```
 

src/_dialog.scss

@@ -17,8 +17,8 @@
       padding: var(#{$prefix}spacing);
     }
 
-    :where(dialog::backdrop) {
-      background: rgb(0 0 0 / 0.5);
+    dialog::backdrop {
+      background: rgb(0 0 0 / 0.8);
     }
 
   }