ui: 修复注册按钮显示异常的问题

packages/ui-default/templates/partials/header_mobile.html

@@ -2,7 +2,7 @@
 <div class="header--mobile">
   <div class="row"><div class="columns clearfix">
     <div class="float-left">
-        <a class="header--mobile__domain is--system" href="/" target="_self">&nbsp;</a>
+      <a class="header--mobile__domain is--system" href="/" target="_self">&nbsp;</a>
     </div>
     <div class="float-right">
       {% include "partials/hamburger.html" %}