remove unused CSS

Signed-off-by: WaitSpring <me@waitspring.com>

resources/screen-mobile.less

@@ -208,8 +208,6 @@
 .mobile-close-button {
 	position: absolute;
 	z-index: 100;
-	top: 0.25em;
-	right: 0;
 	display: none;
 	width: 2em;
 	margin: 0;
@@ -224,22 +222,6 @@
 	padding: 1em 0;
 }
 
-#site-navigation .mobile-close-button {
-	left: 1.25em;
-}
-
-#p-search .mobile-close-button {
-	left: 4.25em;
-}
-
-#mw-related-navigation .mobile-close-button {
-	padding: 1em 0.25em;
-}
-
-#user-tools #personal .mobile-close-button {
-	right: 1.25em;
-}
-
 /* Logo */
 
 #p-logo-text {