style(frontend): remove unnecessary closing center tag

删除了多余的</center>闭合标签，修复页面结构不规范问题

static/public/dnfs.html

@@ -22,7 +22,6 @@
 				点赞：<span id="like-count">999</span>
 				分享：<span id="share-count">999</span>
 			</div>
-			</center>
 			<div id="article-content">hello</div>
 			<div class="recommend-list" id="recommend-list"></div>
 			<br>