Disable selection of colon dividers in header

_sass/helpers.scss

@@ -25,4 +25,13 @@ p {
 
 body.wide {
     max-width: 60rem !important;
+}
+
+.no-select {
+    -webkit-touch-callout: none; /* iOS Safari */
+    -webkit-user-select: none; /* Safari */
+    -khtml-user-select: none; /* Konqueror HTML */
+    -moz-user-select: none; /* Firefox */
+    -ms-user-select: none; /* Internet Explorer/Edge */
+    user-select: none; /* Non-prefixed version, currently supported by Chrome and Opera */
 }