add a fallback in case animations aren't supported but it doesn't matter because netsurf doesn't support @supports???

assets/animations.css

@@ -117,3 +117,10 @@ html {
     animation: 4.5s 1 linear js;
     position: fixed;
 }
+
+@supports not (animation: 1s test) {
+    .nojs {
+        display: block;
+        visibility: visible
+    }
+}