add label hover style for ability to make it a link

less/labels.less

@@ -1,6 +1,7 @@
 // LABELS
 // ------
 
+// Base
 .label {
   padding: 2px 4px 3px;
   font-size: @baseFontSize * .85;
@@ -10,11 +11,22 @@
   background-color: @grayLight;
   .border-radius(3px);
 }
-.label-important { background-color: @errorText; }
-.label-warning   { background-color: @orange; }
-.label-success   { background-color: @successText; }
-.label-info      { background-color: @infoText; }
+
+// Hover state
 .label:hover {
   color: @white;
   text-decoration: none;
 }
+
+// Colors
+.label-important        { background-color: @errorText; }
+.label-important:hover  { background-color: darken(@errorText, 10%); }
+
+.label-warning          { background-color: @orange; }
+.label-warning:hover    { background-color: darken(@orange, 10%); }
+
+.label-success          { background-color: @successText; }
+.label-success:hover    { background-color: darken(@successText, 10%); }
+
+.label-info             { background-color: @infoText; }
+.label-info:hover       { background-color: darken(@infoText, 10%); }