Open _navbar.less in your editor.

Search to find the selector .navbar-default. We have used this class in our navbar markup to apply default styles. You should find it under the commented section for // Alternate navbars.

Within this nested set of rules, find the selector .navbar-nav and the > li > selector nested beneath it. This is where we want to adjust our icon colors.

Under the statement defining nav item link colors, we'll nest a rule to make our icons a lighter shade, using our variable @gray-light, as follows:

.navbar-nav {
  > li > a {
    color: @navbar-default-link-color;

    .icon { // added rule set
      color: @gray-light;
    }