Better contrast on wikitable borders

Bug: T220255
Change-Id: If19024a9566e55078036d3429251f832099e30b1

resources/screen-common.less

@@ -714,6 +714,10 @@ body :not( :checked ) > .toctogglespan:after {
 	.box;
 }
 
+.wikitable {
+	border-color: @base70;
+}
+
 .mw-body .mw-search-profile-tabs {
 	padding: 0.5em;
 }
@@ -722,13 +726,13 @@ body :not( :checked ) > .toctogglespan:after {
 .wikitable > tr > td,
 .wikitable > * > tr > th,
 .wikitable > * > tr > td {
-	border: 1px solid @base80;
+	border: 1px solid @base70;
 	padding: 0.5em;
 }
 
 .wikitable > tr > th,
 .wikitable > * > tr > th {
-	border: 0;
+	border-bottom-width: 2px;
 }
 
 /* Color bars */