如何在导航栏切换中更改下拉菜单中链接的颜色

我的导航栏有一个下拉菜单,看起来像这样。 当我调整浏览器大小以获得小型设备版本时,它看起来是这样的。

我想将下拉列表(服务)中链接的颜色更改为黑色,但我不知道要为CSS选择哪个类。 我试过了,但没有成功。

.dropdown-menu {
     display: none;
     position: absolute;
     background-color: #00ff99;
     min-width: 160px;
     box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
     z-index: 1;
}
.dropdown-menu > li > a {
     float: none;
     color: black;
     padding: 12px 16px;
     text-decoration: none;
     display: block;
     text-align: left;
}
.navbar-toggle .dropdown-menu > li > a{
     color: black;
}

这是我的HTML

<div class="navbar navbar-inverse navbar-fixed-top">
<div class="container">
<div class="navbar-header">
   <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse">
   <span class="icon-bar"></span>
   <span class="icon-bar"></span>
   <span class="icon-bar"></span>
   </button>
   @Html.ActionLink("E-HealthCare", "About", "Home", new { area = "" }, new { @class = "navbar-brand shadow" })
</div>
<div class="navbar-collapse collapse">
<ul class="nav navbar-nav">
   <li>@Html.ActionLink("Home", "About", "Home")</li>
   @*
   <li>@Html.ActionLink("About", "About", "Home")</li>
   <li>@Html.ActionLink("Contact", "Contact", "Home")</li>
   <li>@Html.DropDownList("Services","ALL")</li>
   *@
   <li>
      <div class="dropdown">
         <button class="Dropdown-btn btn-block text-left dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-expanded="false">
         Services
         <span class="caret"></span>
         </button>
         <ul class="dropdown-menu" aria-labelledby="dropdownMenu1">
            <li><a href="#">Action</a></li>
            <li><a href="#">Another action</a></li>
            <li><a href="#">Something else here</a></li>
            <li role="separator" class="divider"></li>
            <li><a href="#">Separated link</a></li>
         </ul>
      </div>
   </li>
</ul>