Uniform media and video spoiler settings and fix them of the light theme (#7778)

app/javascript/styles/mastodon-light/diff.scss

@@ -87,6 +87,17 @@
   }
 }
 
+// Change the background colors of media and video spoiler
+
+.media-spoiler,
+.video-player__spoiler {
+  background: $ui-base-color;
+}
+
+.account-gallery__item a {
+  background-color: $ui-base-color;
+}
+
 // Change the colors used in the dropdown menu
 .dropdown-menu {
   background: $ui-base-color;

app/javascript/styles/mastodon/components.scss

@@ -4555,7 +4555,7 @@ a.status-card {
     height: 100%;
     z-index: 4;
     border: 0;
-    background: $base-shadow-color;
+    background: $base-overlay-background;
     color: $darker-text-color;
     transition: none;
     pointer-events: none;