Enlarge text difficult level for one second (make it work using vanilla JavaScript)

app/templates/userpage_get.html

@@ -204,8 +204,9 @@
         $('#source').html(today_article['source']);
         $('#question').html(today_article["question"]);
         $('#answer').html(today_article["answer"]);
-        $('#text_level').classList.add('display-5'); // enlarge text difficult level for one second
-        setTimeOut(() => {$('#text_level').classList.remove('display-5');}, 1000);
+        document.querySelector('#text_level').classList.add('display-5'); // enlarge text difficult level for one second
+
+        setTimeout(() => document.querySelector('#text_level').classList.remove('display-5'), 800);
     }
 <!-- 检查是否存在上一篇或下一篇，不存在则对应按钮隐藏-->
     function check_pre(visited_articles){