Use bootstrap variable for table color

IPython/html/static/tree/less/tree.less

@@ -1,221 +1,221 b''
 
 /**
  * Primary styles
  *
  * Author: IPython Development Team
  */
 
 @dashboard_tb_pad: 4px;
 @dashboard_lr_pad: 7px;
 // These are the total heights of the Bootstrap small and mini buttons. These values
 // are not less variables so we have to track them statically.
 @btn_small_height: 24px;
 @btn_mini_height: 22px;
 @dark_dashboard_color: @breadcrumb-color;
 
 ul#tabs {
     margin-bottom: @dashboard_tb_pad;
 }
 
 ul#tabs a {
     padding-top: @dashboard_tb_pad + 2px;
     padding-bottom: @dashboard_tb_pad;
 }
 
 ul.breadcrumb {
     a:focus, a:hover {
         text-decoration: none;
     }
     i.icon-home {
         font-size: 16px;
         margin-right: 4px;
     }
     
     span {
         color: @dark_dashboard_color;
     }
 }
 
 .list_toolbar {
     padding: @dashboard_tb_pad 0 @dashboard_tb_pad 0;
     vertical-align: middle;
 
     .tree-buttons {
         padding-top: 2px;
     }
 }
 
 .list_toolbar [class*="span"] {
     min-height: @btn_small_height;
 }
 
 .list_header {
     font-weight: bold;
 }
 
 .list_container {
   margin-top: @dashboard_tb_pad;
   margin-bottom: 5*@dashboard_tb_pad;
   border: 1px solid @border_color;
   border-radius: @border-radius-base;
 }
 
 .list_container > div {
   border-bottom: 1px solid @border_color;
   &:hover .list-item{
     background-color: red;
   };
 }
 
 .list_container > div:last-child {
   border: none;
 }
 
 .list_item {
   &:hover .list_item {
-    background-color: #ddd;
+    background-color: @table-border-color;
   };
   a {text-decoration: none;}
 }
 
 .action_col {
     text-align: right;
 }
 
 .list_header>div, .list_item>div {
     padding-top: @dashboard_tb_pad;
     padding-bottom: @dashboard_tb_pad;
     padding-left: @dashboard_lr_pad;
     padding-right: @dashboard_lr_pad;
     line-height: @btn_mini_height;
 }
 
 .item_name {
     line-height: @btn_mini_height;
     height: @btn_small_height;
 }
 
 .item_icon {
     font-size: 14px; 
     color: @dark_dashboard_color;
     margin-right: @dashboard_lr_pad;
 }
 
 .item_buttons {
     line-height: 1em;
     .btn {
         min-width: 13ex;
     }
     .btn-toolbar();
 }
 
 .toolbar_info {
     height: @btn_small_height;
     line-height: @btn_small_height;
 }
 
 input.nbname_input, input.engine_num_input {
     // These settings give these inputs a height that matches @btn_mini_height = 22
     padding-top: 3px;
     padding-bottom: 3px;
     height: @btn_mini_height;
     line-height: 14px;
     margin: 0px;
 }
 
 input.engine_num_input {
     width: 60px;
 }
 
 .highlight_text {
     color: blue;
 }
 
 #project_name > .breadcrumb {
     padding: 0px;
     margin-bottom: 0px;
     background-color: transparent;
     font-weight: bold;
    
 }
 
 .tab-content .row {
     margin-left: 0px;
     margin-right: 0px;
 }
 
 .folder_icon:before {
     .icon(@fa-var-folder-o)
 }
 
 .notebook_icon:before {
     .icon(@fa-var-book)
 }
 
 .file_icon:before {
     .icon(@fa-var-file-o)
 }
 
 ul#new-menu {
     // align right instead of left
     left: auto;
     right: 0;
 }
 
 .kernel-menu-icon {
     padding-right: 12px;
     width: 24px;
     content: @fa-var-square-o;
 }
 
 .kernel-menu-icon:before {
     content: @fa-var-square-o;
 }
 
 .kernel-menu-icon-current:before {
     content: @fa-var-check;
 }
 
 #tab_content {
     padding-top: @page-header-padding;
 }
 
 #running {
     .panel-group{
         .panel {
             margin-top: 15px;
 
             .panel-heading {
                 background-color: @page-backdrop-color;
                 padding-top: @dashboard_tb_pad;
                 padding-bottom: @dashboard_tb_pad;
                 padding-left: @dashboard_lr_pad;
                 padding-right: @dashboard_lr_pad;
                 line-height: @btn_mini_height;
                 
                 a:focus, a:hover {
                     text-decoration: none;
                 }
             }
 
             .panel-body {
                 padding: 0px;
 
                 .list_container {
                     margin-top: 0px;
                     margin-bottom: 0px;
                     border: 0px;
                     border-radius: 0px;
 
                     .list_item {
-                        border-bottom: 1px solid #ddd;
+                        border-bottom: 1px solid @table-border-color;
 
                         &:last-child {
                             border-bottom: 0px;
                         }
                     }
                 }
             }
         }
     }
 }