Make "half width" divs clear for smaller displays

html/style.css

@@ -13,6 +13,12 @@ a:hover {
 	color: #00c;
 }
 
+@media screen and (max-width: 1023px) {
+    .pure-u-12-24 {
+        width: 100%;
+    }
+}
+
 .card {
 	background-color: #eee;
 	padding: 1em;