ignore: hidden value until-found

normalize.css

@@ -342,8 +342,9 @@ template {
 
 /**
  * Add the correct display in IE 10.
+ * Except `hidden="until-found"`　because `content-visibility: hidden` is applied.
  */
 
-[hidden] {
+[hidden]:not([hidden="until-found"]) {
   display: none;
 }

test.html

@@ -142,6 +142,7 @@
       <content></content>
     </template>
     <p hidden>This should be hidden</p>
+    <p hidden="until-found">This is not display none</p>
   </div>
 
   <h2 class="Test-describe"><code>a</code></h2>