Fix .social-share-button-qq background image position

@media only screen and (-webkit-device-pixel-ratio: 2) {
...
.social-share-button-qq
...
}

app/assets/stylesheets/social-share-button.scss

@@ -56,7 +56,7 @@
   .social-share-button-google_plus { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) -16px -32px no-repeat; background-size:64px 64px;}
   .social-share-button-kaixin001 { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) -32px -32px no-repeat; background-size:64px 64px;}
   .social-share-button-plurk { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/social-share-button.png')) -48px 0px no-repeat; background-size:64px 64px; }
-  .social-share-button-qq { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) -48px 16px no-repeat; background-size:64px 64px;}
+  .social-share-button-qq { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) -48px -16px no-repeat; background-size:64px 64px;}
   .social-share-button-renren { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) -48px -32px no-repeat; background-size:64px 64px;}
   .social-share-button-tqq { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) 0px -48 no-repeat; background-size:64px 64px;}
   .social-share-button-tumblr { display:inline-block; width: 16px; height: 16px; background: url(image-path('sprites/[email protected]')) -16px -48px no-repeat; background-size:64px 64px;}