Style for clickable column names.

web/assets/css/main.css

@@ -153,6 +153,26 @@ td a:hover { transition: none; }
 td:nth-child(2),
 td:last-child { white-space: nowrap; }
 
+thead tr th.clickable {
+	cursor: pointer;
+}
+
+thead tr th.clickable:hover {
+	color: var(--secondary-color);
+}
+
+thead tr th.clickable:not(.sort-up):not(.sort-down)::after {
+	content: '⇅';
+}
+
+thead tr th.clickable.sort-up::after {
+	content: '↑';
+}
+
+thead tr th.clickable.sort-down::after {
+	content: '↓';
+}
+
 footer {
 	font-size: .8rem;
 	text-align: center;