问更改活动导航栏的颜色

EN

<div class="navbar">
    <div class="navbar-fixed-top">
      <div class="container" style="width: auto;">
          <div class="nav-collapse" id="nav-collapse">
          <ul class="nav" id="nav">
            <li class="active"><a href="#skdill" >skisll</a></li>
            <li class="active"><a href="#skill">skill</a></li>
            <li class="active"><a href="#research">research</a></li>
            <li class="active"><a href="#">Link</a></li>
                     </ul>
        </div>
      </div>
    </div>
  </div>

.navbar {
    position: fixed;
    width: 100%;
}
.navbar .nav {
   float: none;
}
.navbar .nav>li {
    width: 25%;
}
.content {
    padding-top: 80px;
}

#nav-collapse li a:hover { 
    color: blue; 
}
#nav-collapse a:hover { 

    background-color: gray; 
}

#nav-collapse  li.active { 
   color:green;
    background-color: yellow; 
}
#nav-collapse  li.active a {
    color: red;
}