如何移除Bootstrap导航栏左侧内边距/外边距并居中导航项

我来帮你搞定这个导航栏居中的问题！你遇到的轻微左偏，主要是两个原因：一是navbar-nav上的mr-auto类和mx-auto冲突，二是Bootstrap默认给.navbar和.navbar-collapse加了内边距/对齐规则。

下面是具体的修复步骤和修改后的代码：

1. 修正导航栏的对齐类 #

你原本给navbar-nav加了mr-auto mx-auto，其中mr-auto会强制元素向左对齐，和mx-auto（通过左右自动margin实现居中）的作用冲突，只需要保留mx-auto即可。

2. 移除Bootstrap默认的边距和对齐规则 #

添加自定义CSS覆盖Bootstrap的默认样式，确保导航栏容器没有多余的内边距，并且折叠区域也能保持居中对齐：

body { margin: 0; padding: 0; font-family: 'Roboto', sans-serif; }
/* Header Start */
header { display: flex; height: 10rem; align-items: center; justify-content: center; }
nav ul li { padding-left: 10px; padding-right: 10px; }
nav { font-size: 21px; }
#logo img { height: 220px; }
/* Header End */
/* 新增导航栏居中样式 */
.navbar {
  padding-left: 0;
  padding-right: 0;
}
.navbar-collapse {
  justify-content: center;
}
/* Navigation End */
/* Main Start */
/* Main End */
/* Aside Start */
/* Aside End */
/* Footer Start */
/* Footer End */
/* Media Queries Start */
/* Media Queries End */

3. 修改后的HTML代码 #

主要调整navbar-nav的类，移除冲突的mr-auto：

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<meta name="viewport" content="width=device-width,initial-scale=1">
<meta name="description" content="opis strony">
<meta name="robots" content="index, follow">
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css" integrity="sha384-Vkoo8x4CGsO3+Hhxv8T/Q5PaXtkKtu6ug5TOeNV6gBiFeWPGFN9MuhOf23Q9Ifjh" crossorigin="anonymous">
<link rel="stylesheet" href="css/style.css">
<link href="https://fonts.googleapis.com/css?family=Roboto&amp;display=swap" rel="stylesheet">
</head>
<body>
<header>
<div id="logo"><img src="img/logotest.jpg" alt="" class="img-fluid"></div>
</header>
<nav class="navbar navbar-expand-md navbar-light bg-light">
<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="navbarSupportedContent">
<ul class="navbar-nav mx-auto">
<li class="nav-item active">
<a class="nav-link" href="#">Home <span class="sr-only">(current)</span></a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Articles</a>
</li>
<li class="nav-item">
<a class="nav-link" href="#">Reviews</a>
</li>
</ul>
</div>
</nav>
<main>
</main>
<aside>
</aside>
<footer>
</footer>
<script src="https://code.jquery.com/jquery-3.4.1.slim.min.js" integrity="sha384-J6qa4849blE2+poT4WnyKhv5vZF5SrPo0iEjwBvKU7imGFAV0wwj1yYfoRSJoZ+n" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.16.0/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js" integrity="sha384-wfSDF2E50Y2D1uUdj0O3uMBJnjuUD4Ih7YwaYd1iqfktj0Uod8GCExl3Og8ifwB6" crossorigin="anonymous"></script>
</body>
</html>

这样修改后，导航项就会完美居中，不会再有左偏的问题啦！

内容的提问来源于stack exchange，提问作者Michał Markiewicz