Index: src/assets/css/style.css
===================================================================
--- src/assets/css/style.css	(revision 97bcf7e177ca103298874640116738590712ff8c)
+++ src/assets/css/style.css	(revision 6dd26e55b97a257fb828412f04951bb77f39914a)
@@ -2421,4 +2421,14 @@
 .grid-tile-img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; object-position: center; display: block; transition: opacity .4s ease; }
 .grid-tile-img.is-loading { opacity: 0; }
+/* Audio tile (Shaer, Robins vraag 30-7): the waveform PNG is white on
+   transparent and floats OVER the tile's own hue gradient, so every audio
+   post keeps its color and gets its shape. Contain + padding leaves the
+   centered title readable. */
+.grid-tile-img.grid-tile-wave {
+    background-color: transparent;
+    object-fit: contain;
+    padding: 26% 10%;
+    opacity: .85;
+}
 /* Cover videos are decorative, not players: let clicks + right-click pass through to the
    tile link so you get the normal link menu (not the browser's <video> menu/controls).