Remove ugly blue highlight on Android browsers (#4031)

app/javascript/styles/basics.scss

@@ -11,6 +11,8 @@ body {
   text-rendering: optimizelegibility;
   font-feature-settings: "kern";
   text-size-adjust: none;
+  -webkit-tap-highlight-color: rgba(0,0,0,0);
+  -webkit-tap-highlight-color: transparent;
 
   &.app-body {
     position: fixed;