diff --git a/src/facets/themes/winamp/browser/element.js b/src/facets/themes/winamp/browser/element.js
index 16595fc0..82f03820 100644
--- a/src/facets/themes/winamp/browser/element.js
+++ b/src/facets/themes/winamp/browser/element.js
@@ -245,7 +245,13 @@ this.#renderIfWindowChanged();
       );
 
       this.#resizeObserver = new ResizeObserver((entries) => {
-        this.#viewportHeight = entries[0].contentRect.height;
+        // Cap to window.innerHeight to guard against measuring the scroll height
+        // before shadow DOM stylesheets finish loading (when the panel has no
+        // flex constraints and expands to its full virtual content size).
+        this.#viewportHeight = Math.min(
+          entries[0].contentRect.height,
+          window.innerHeight,
+        );
         this.#renderIfWindowChanged();
       });