如何將懸停動畫添加到引導導航欄鏈接？

Question

我試圖將在這里找到的導航動畫之一添加到我的引導導航中。 添加類沒有用，更改導航欄css也沒有用，所以我需要一些幫助。

導航HTML：

    <div class="navbar navbar-default navbar-fixed-top" role="navigation">
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
      <a class="navbar-brand" href="index-en.html"><img class = "logo" src = "logo.png" alt = ""></a>
        </div>

    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
        <ul class="nav navbar-nav navbar-right">
            <li class="active"><a class = "active" href="#">Home</a></li>       
            <li><a href="about.html">About us</a></li>
            <li><a href="employees.html">Employees</a></li>       
            <li><a href="where.html">Where we are</a></li>

        <li><div class="btn-group"> 
          <a href="index.html" class="btn btn-default"><img src="img/hr.png" alt="" title = "Hrvatski" > </a>

        </div></li>
        </ul>
    </div>


    </div><!--/.nav-collapse -->
  </div>

當前相關的CSS：

.navbar-default .navbar-nav > li > a {
   color: #4E4F51!important;
   text-transform: uppercase!important;
   font-size: 15px;
}
.navbar-default .navbar-nav > .active  > a,
.navbar-default .navbar-nav > .active  > a:hover,
.navbar-default .navbar-nav > .active  > a:focus {
   color: #3BB34A!important;
   background-color: transparent!important;
}

.navbar-default .navbar-nav > li > a:hover,
.navbar-default .navbar-nav > li > a:focus {
   color: #3AB44A!important;
   background-color: transparent!important;
}

那么，如何實現從上述鏈接到我的導航欄的動畫之一？

Answer 1

  <div class="navbar navbar-default navbar-fixed-top" role="navigation">
    <div class="container">
        <div class="navbar-header">
            <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
                <span class="sr-only">Toggle navigation</span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
                <span class="icon-bar"></span>
            </button>
      <a class="navbar-brand" href="index-en.html"><img class = "logo" src = "logo.png" alt = ""></a>
        </div>

    <div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
        <ul class="nav navbar-nav navbar-right  pullDown">
            <li class="active"><a class = "active" href="#">Home</a></li>       
            <li><a href="about.html">About us</a></li>
            <li><a href="employees.html">Employees</a></li>       
            <li><a href="where.html">Where we are</a></li>

        <li><div class="btn-group"> 
          <a href="index.html" class="btn btn-default"><img src="img/hr.png" alt="" title = "Hrvatski" > </a>

        </div></li>
        </ul>
    </div>


    </div><!--/.nav-collapse -->
  </div>

  // add this in your css
  li.pullDown a:before
   {
    position: absolute;
    width: 100%;
    height: 2px;
    left: 0px;
    top: 0px;
    content: '';
    background: #FFF;
    opacity: 0.3;
    transition: all 0.3s;
   }

  li.pullDown a:hover:before
   {
    height: 100%;
   }

Answer 2

好吧，我想通了，只需要添加這個選擇器：

.navbar-default .navbar-nav > li > a:before {
   position: absolute;
   width: 100%;
   height: 2px;
   left: 10px;
   bottom: 45px;
   content: '';
   background: green;
   opacity: 0.3;
   transition: all 0.3s;
}
.navbar-default .navbar-nav > li > a:hover:before{
   height: 100%;
}

我之前可能已經嘗試過，但是背景色設置為#FFF（與navbar相同），所以我看不到任何動畫。 無論如何，謝謝您的建議。