Fix incorrect CSS selector

Author: user890104

src/style.css

@@ -29,10 +29,10 @@
 
 /* include the switch.btn itself */
 .btn-group-xs > switch.btn,
-switch.btn-xs,
+.switch.btn-xs,
 /* include .btn elements inside the switch */
 .btn-group-xs > switch .btn,
-switch .btn-xs
+.switch .btn-xs
 {
 	padding: .35rem .4rem .25rem .4rem;
 	font-size: .875rem;