Improve dark-mode hero contrast

Dark mode now dims the home hero screenshot and restores it on hover for better readability without losing the preview effect. This keeps the landing page visually balanced in low-light themes.

Author: ruibaby

styles/index.scss

@@ -110,6 +110,17 @@
   border-radius: 5px;
 }
 
+.rp-dark {
+  .docs-hero__shot {
+    filter: brightness(0.7);
+    transition: filter 180ms ease;
+
+    &:hover {
+      filter: unset;
+    }
+  }
+}
+
 .docs-home a:focus-visible {
   outline: 2px solid var(--rp-c-brand);
   outline-offset: 3px;