use a class to hide hidden (e.g. blocked) elements

Former-commit-id: 741a511243f43231f5c7721a7f9c7d16f08c9f3a

lib/single-file/single-file-core.js

@@ -789,7 +789,12 @@ this.singlefile.lib.core = this.singlefile.lib.core || (() => {
 			const removedElements = this.doc.querySelectorAll("[" + util.REMOVED_CONTENT_ATTRIBUTE_NAME + "]");
 			this.stats.set("discarded", "hidden elements", removedElements.length);
 			this.stats.set("processed", "hidden elements", removedElements.length);
-			hiddenElements.forEach(element => element.hidden = true);
+			if (hiddenElements.length) {
+				const styleElement = this.doc.createElement("style");
+				styleElement.textContent = ".sf-hidden{display:none!important;}";
+				this.doc.head.appendChild(styleElement);
+				hiddenElements.forEach(element => element.classList.add("sf-hidden"));
+			}
 			removedElements.forEach(element => element.remove());
 		}