add table alternate row styling

core/css/theme.css

@@ -17,6 +17,8 @@
 	--secondary-container-background: #cacaca;
 	--secondary-container-border: 2px outset #c1c1c1;
 	
+	--table-alternate: #dbdbdb;
+	
 	--header-bg: #ffffff;
 	--header-text: #000000;
 	--header-line: 2px solid #000000;