Index: src/assets/css/style.css
===================================================================
--- src/assets/css/style.css	(revision 3507b0bab5d351cf1606b8140e90ac366ab4f8e2)
+++ src/assets/css/style.css	(revision 5045c30366c334b867cb852425f5cc48dcb1323b)
@@ -2372,4 +2372,10 @@
     -webkit-tap-highlight-color: rgba(0,0,0,.1);
 }
+
+/* Transparent covers (PNG logos etc.) sit on white everywhere so they don't blend
+   into a dark theme. Opaque covers fully cover the white — no visible change. */
+.post-cover img,
+.post-list-cover img,
+.grid-tile:not(.grid-tile-gradient) { background-color: #fff; }
 .grid-tile:hover { transform: scale(0.98); }
 .grid-tile-overlay {