Add styling for featured content iframe.

jellyfin.css

@@ -29,6 +29,19 @@
 }
 */
 
+.featurediframe {
+  border-radius: var(--rounding) !important;
+  border: transparent;
+  height: 200px;
+  margin-bottom: 30px;
+}
+
+@media only screen and (max-device-width: 767px) {
+  .featurediframe {
+    height: 16vh !important;
+  }
+}
+
 @media (min-device-width: 900px) {
   .section0 .overflowBackdropCard, .section0 .overflowSmallBackdropCard {
     width: 14vw;