enh: iframe support

src/app.html

@@ -13,6 +13,12 @@
 			href="/opensearch.xml"
 		/>
 
+		<script>
+			function resizeIframe(obj) {
+				obj.style.height = obj.contentWindow.document.documentElement.scrollHeight + 'px';
+			}
+		</script>
+
 		<script>
 			// On page load or when changing themes, best to add inline in `head` to avoid FOUC
 			(() => {