Header 按钮悬停颜色

Header Button Hover Colour

我刚接触网络开发大约 2 周,我正在制作一个网站。我一直试图让悬停在 header 按钮上起作用,但我找不到解决方案。这是代码。

HTML:

    <!DOCTYPE html>
<html lang="en">

<head>
    <title>Home</title>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" type="text/css" href="style.css">
    <link href='http://fonts.googleapis.com/css?family=PT+Sans' rel='stylesheet' type='text/css'>
    <script src="http://timthumb.googlecode.com/svn/trunk/timthumb.php"></script>
</head>

<body>
    <div class="banner">
    </div>
    <div class="nav">
      <ul>
        <li><a class="active" href="#">Home</a></li>
        <li><a href="#">About Us</a></li>
        <li><a href="#">FAQ</a></li>
        <li><a href="#">ORBAT</a></li>
      </ul>

    </div>

CSS:

/*stylesheet */

body {
    margin: 0;
    padding: 0;
    background: #ccc;
    overflow-x: hidden;
    font-family: 'PT Sans'
}

/*header*/
.banner {
    background-image: url('http://www.respectfulrevolution.org/sites/all/themes/curiouser_respect/graphics/header.png'); 
    width: 100%;
    height: 100px;
}
.nav {
    width: 100%;
    height: 90px;
    position: fixed;
    background-color: #444;

}
.nav ul {
    list-style: none; 
}
.nav  li{
    display: inline-block;
    padding: 15px 20px 15px 20px;
    margin: 0;
    background-color: #3f3f3f;
}
.nav a {
    text-decoration: none;
    color: #fff;
    font-size: 1.250em;
}
.nav a:hover {
    background-color: #028482;
    opacity: 50%;
}
/*end of header*/

我已经尝试过相对位置和显示块之类的东西。

请检查此 CSS 代码:

.nav {
  width: 100%;
  position: relative;
  background-color: #444;
  min-height: 1px;
}
.nav:after,
.nav:before{
  display: table;
  content: " ";
  clear: both;
}
.nav ul {
  list-style: none; 
}
.nav li{
  display: inline-block;
  margin: 0;
}
.nav li a {
  border-radius: 3px;
  text-decoration: none;
  color: #fff;
  font-size: 1.250em;
  padding: 15px;
  background-color: #3f3f3f;
  transition: background 0.3s ease, color 0.3s ease;
  -webkit-transition: transition: background 0.3s ease, color 0.3s ease;
  -moz-transition: transition: background 0.3s ease, color 0.3s ease;
}
.nav li a:hover,
.nav li a:focus {
  background-color: #028482;
  transition: background 0.3s ease, color 0.3s ease;
  -webkit-transition: transition: background 0.3s ease, color 0.3s ease;
  -moz-transition: transition: background 0.3s ease, color 0.3s ease;
}
.nav li a.active{
  background-color: #028482 !important;
  transition: background 0.3s ease, color 0.3s ease;
  -webkit-transition: transition: background 0.3s ease, color 0.3s ease;
  -moz-transition: transition: background 0.3s ease, color 0.3s ease;
}

看这里:https://jsfiddle.net/nkjp2uj3/2/