Restyle tree table UI

app/assets/stylesheets/gitlab_bootstrap/tables.scss

@@ -17,11 +17,11 @@ table {
   }
 
   th {
-    font-weight: bold;
+    font-weight: normal;
+    font-size: 15px;
     vertical-align: middle;
     border-bottom: 1px solid #CCC;
     text-shadow: 0 1px 1px #fff;
-    @include bg-dark-gray-gradient;
 
     ul.nav {
       text-shadow: none;

app/assets/stylesheets/sections/tree.scss

@@ -57,13 +57,17 @@
   }
 
   .tree-table {
+    border: none;
+
     th .btn {
       margin: -2px -1px;
       padding: 2px 10px;
     }
     td {
       line-height: 20px;
-      background: #fafafa;
+      background: #fff !important;
+      border-left: none;
+      border-right: none;
     }
   }