.btn-default to .btn-secondary

docs/examples/cover/cover.css

@@ -10,9 +10,9 @@ a:hover {
 }
 
 /* Custom default button */
-.btn-default,
-.btn-default:hover,
-.btn-default:focus {
+.btn-secondary,
+.btn-secondary:hover,
+.btn-secondary:focus {
   color: #333;
   text-shadow: none; /* Prevent inheritence from `body` */
   background-color: #fff;

docs/examples/cover/index.html

@@ -53,7 +53,7 @@
             <h1 class="cover-heading">Cover your page.</h1>
             <p class="lead">Cover is a one-page template for building simple and beautiful home pages. Download, edit the text, and add your own fullscreen background photo to make it your own.</p>
             <p class="lead">
-              <a href="#" class="btn btn-lg btn-default">Learn more</a>
+              <a href="#" class="btn btn-lg btn-secondary">Learn more</a>
             </p>
           </div>