Issue 2410 - Improved accessibility of dialogs in options page

skin/options.css

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 237 matching lines @@
 }
 
 #tab-share .icon
 {
   background-position: -61px -18px;
 }
 
 #tab-contribute .icon
 {
   background-position: -31px -18px;
+}
+
+#tab-share:lang(zh),
+#tab-share[hidden]
+{
+  display: none;
+}
+
+#tab-share:lang(zh) + li,
+#tab-share[hidden] + li
+{
+  border-top: none;
 }
 
 #tab-content
 {
   background-color: #FFFFFF;
   border: 1px solid #CDCDCD;
   border-radius: 8px;
   box-sizing: border-box;
   min-width: 960px;
   padding: 0px 60px 40px 60px;
@@ skipping 773 matching lines @@
 #dialog-body button
 {
   background-color: #F5F5F5;
   border: none;
   color: #3A7BA6;
   cursor: pointer;
   display: block;
   font-family: inherit;
   margin-top: 8px;
   padding: 10px 16px;
-  text-align: left;
+  text-align: initial;
   width: 100%;
 }
 
 #dialog .url
 {
   margin-top: 10px;
   margin-bottom: 20px;
   word-wrap: break-word;
 }
 
@@ skipping 25 matching lines @@
 #other-language .button-add::before
 {
   display: none;
 }
 
 #other-language .display
 {
   -webkit-margin-start: 10px;
   -moz-margin-start: 10px;
 }