css3 - Unable to change Bootstrap CSS Nav Bar Color -

i using bootstrap css navbar , cannot change color of text inside navbar. html code:

    <nav class="navbar navbar-default navbar-fixed-top" ng-controller="navctrl">        <ul class = "nav navbar-nav">          <li><a class = "nav_color"><span class="glyphicon glyphicon-user"></span> username </a></li>           <li><a class = "nav_color"><span class="glyphicon glyphicon-book"></span> book </a></li>           <li><a class = "nav_color"><span class="glyphicon glyphicon-pencil"></span> pencil </a></li>        </ul>     </nav> 

and here css code:

    .nav_color {        color: red;     } 

i don't understand why isn't working

axc, hi there.

try doing this.

.nav.navbar-nav li {     color: red; }