add table alternate row styling

core/style.css

@@ -57,6 +57,10 @@ textarea, input {
 	box-sizing: border-box;
 }
 
+table.alternating tr:nth-of-type(even) {
+	background: var(--table-alternate);
+}
+
 @media only screen and (orientation: landscape) {
 	:target::before {
 		content: "";