我试图通过让 main.css（见下文）覆盖导航类来覆盖默认的 Twitter Bootstrap Nav，但未应用更改。
这是我的 index.html
<!DOCTYPE html>
<!--[if lt IE 7]> <html class="no-js lt-ie9 lt-ie8 lt-ie7"> <![endif]-->
<!--[if IE 7]> <html class="no-js lt-ie9 lt-ie8"> <![endif]-->
<!--[if IE 8]> <html class="no-js lt-ie9"> <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js"> <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title></title>
<meta name="description" content="">
<meta name="viewport" content="width=device-width">
<link rel="stylesheet" href="css/bootstrap.min.css">
<style>
body {
padding-top: 60px;
padding-bottom: 40px;
}
</style>
<link rel="stylesheet" href="css/bootstrap-responsive.min.css">
<link rel="stylesheet" href="css/main.css">
<script src="js/vendor/modernizr-2.6.2-respond-1.1.0.min.js"></script>
</head>
<body>
<!--[if lt IE 7]>
<p class="chromeframe">You are using an <strong>outdated</strong> browser. Please <a href="http://browsehappy.com/">upgrade your browser</a> or <a href="http://www.google.com/chromeframe/?redirect=true">activate Google Chrome Frame</a> to improve your experience.</p>
<![endif]-->
<!-- This code is taken from http://twitter.github.com/bootstrap/examples/hero.html -->
<div class="navbar navbar-inverse navbar-fixed-top">
<div class="navbar-inner mynav">
<div class="container">
<a class="btn btn-navbar" data-toggle="collapse" data-target=".nav-collapse">
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</a>
<a class="brand" href="#">Project name</a>
<div class="nav-collapse collapse">
<ul class="nav">
<li class="active"><a href="#">Home</a></li>
<li><a href="#about">About</a></li>
<li><a href="#contact">Contact</a></li>
<li class="dropdown">
<a href="#" class="dropdown-toggle" data-toggle="dropdown">Dropdown <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Action</a></li>
<li><a href="#">Another action</a></li>
<li><a href="#">Something else here</a></li>
<li class="divider"></li>
<li class="nav-header">Nav header</li>
<li><a href="#">Separated link</a></li>
<li><a href="#">One more separated link</a></li>
</ul>
</li>
</ul>
<form class="navbar-form pull-right">
<input class="span2" type="text" placeholder="Email">
<input class="span2" type="password" placeholder="Password">
<button type="submit" class="btn">Sign in</button>
</form>
</div><!--/.nav-collapse -->
</div>
</div>
</div>
<div class="container">
<!-- Main hero unit for a primary marketing message or call to action -->
<div class="hero-unit">
<h1>Hello, world!</h1>
<p>This is a template for a simple marketing or informational website. It includes a large callout called the hero unit and three supporting pieces of content. Use it as a starting point to create something more unique.</p>
<p><a class="btn btn-primary btn-large">Learn more »</a></p>
</div>
<!-- Example row of columns -->
<div class="row">
<div class="span4">
<h2>Heading</h2>
<p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
<p><a class="btn" href="#">View details »</a></p>
</div>
<div class="span4">
<h2>Heading</h2>
<p>Donec id elit non mi porta gravida at eget metus. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus. Etiam porta sem malesuada magna mollis euismod. Donec sed odio dui. </p>
<p><a class="btn" href="#">View details »</a></p>
</div>
<div class="span4">
<h2>Heading</h2>
<p>Donec sed odio dui. Cras justo odio, dapibus ac facilisis in, egestas eget quam. Vestibulum id ligula porta felis euismod semper. Fusce dapibus, tellus ac cursus commodo, tortor mauris condimentum nibh, ut fermentum massa justo sit amet risus.</p>
<p><a class="btn" href="#">View details »</a></p>
</div>
</div>
<hr>
<footer>
<p>© Company 2012</p>
</footer>
</div> <!-- /container -->
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script>window.jQuery || document.write('<script src="js/vendor/jquery-1.9.1.min.js"><\/script>')</script>
<script src="js/vendor/bootstrap.min.js"></script>
<script src="js/main.js"></script>
<script>
var _gaq=[['_setAccount','UA-XXXXX-X'],['_trackPageview']];
(function(d,t){var g=d.createElement(t),s=d.getElementsByTagName(t)[0];
g.src=('https:'==location.protocol?'//ssl':'//www')+'.google-analytics.com/ga.js';
s.parentNode.insertBefore(g,s)}(document,'script'));
</script>
</body>
</html>
这是我的 main.css（注意 main.css 在引导 CSS 之后加载）：
/* ==========================================================================
My custom styles
========================================================================== */
.navbar-inverse .navbar-inner{
background-color:#1f5b73;
}
该背景颜色显示在 Chrome 开发工具上，因为当前正在使用的属性和所有其他背景属性似乎已被覆盖，但我仍然看不到更改。