add tau icon

css/colors/blue-dark.css

@@ -426,6 +426,7 @@ body.stop-scrolling {
   height: 100%;
   position: fixed;
   display: none;
+  z-index: 10;
 }
 .table-hover>tbody>tr:hover, .table-striped>tbody>tr:nth-of-type(odd), .table>tbody>tr.active>td, .table>tbody>tr.active>th, .table>tbody>tr>td.active, .table>tbody>tr>th.active, .table>tfoot>tr.active>td, .table>tfoot>tr.active>th, .table>tfoot>tr>td.active, .table>tfoot>tr>th.active, .table>thead>tr.active>td, .table>thead>tr.active>th, .table>thead>tr>td.active, .table>thead>tr>th.active {
   background-color: #1f1f1f!important;