2px border on thead th elements for just a tad more separation

dist/css/bootstrap.css

@@ -1408,6 +1408,7 @@ th {
 
 .table thead > tr > th {
   vertical-align: bottom;
+  border-bottom: 2px solid #dddddd;
 }
 
 .table caption + thead tr:first-child th,
@@ -1449,6 +1450,11 @@ th {
   border: 1px solid #dddddd;
 }
 
+.table-bordered > thead > tr > th,
+.table-bordered > thead > tr > td {
+  border-bottom-width: 2px;
+}
+
 .table-striped > tbody > tr:nth-child(odd) > td,
 .table-striped > tbody > tr:nth-child(odd) > th {
   background-color: #f9f9f9;

less/tables.less

@@ -35,6 +35,7 @@ th {
   // Bottom align for column headings
   thead > tr > th {
     vertical-align: bottom;
+    border-bottom: 2px solid @table-border-color;
   }
   // Remove top border from thead by default
   caption + thead,
@@ -92,6 +93,14 @@ th {
       }
     }
   }
+  > thead {
+    > tr {
+      > th,
+      > td {
+        border-bottom-width: 2px;
+      }
+    }
+  }
 }