Added slightly darker social icons so that they can have some opacity on hover

sass/index/_footer.scss

@@ -63,25 +63,31 @@ footer {
           float: left;
           margin-right: lh(.5);
 
+          &:after {
+            content: none;
+            display: none;
+          }
+
           a {
             display: block;
             height: 29px;
             width: 28px;
             text-indent: -9999px;
-          }
 
-          &:after {
-            content: none;
-            display: none;
+            &:hover {
+              opacity: .8;
+            }
           }
 
           &.twitter a {
             background: url('/static/images/marketing/twitter.png') 0 0 no-repeat;
           }
+
           &.facebook a {
             background: url('/static/images/marketing/facebook.png') 0 0 no-repeat;
           }
-          &.linkedin {
+
+          &.linkedin a {
             background: url('/static/images/marketing/linkedin.png') 0 0 no-repeat;
           }
         }