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![[Web-Frontend] Node.js-Schnellstart](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
这是因为，Bootstrap的导航栏只是默认是51px高，而并非永远是51px高，如果其中有元素出现多行，是会将高度撑高的。
你的demo里，由于有一个标签多了一个Link，所以将整个导航栏撑高了20px。
是不是框架给的? marign:0 或者padding:0 有木有效
你可以在控制台DOM树上找到导航栏，然后一个一个的从里往外删元素，排查到是哪个元素导致的