minor #840 Minor design tweak for smartphones (javiereguiluz)

This PR was merged into the master branch.

Discussion
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Minor design tweak for smartphones

This fixes #829 hiding the icon when browsing the site in a smartphone.

Commits
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b6d1b16 Minor design tweak for smartphones

Author: javiereguiluz

templates/security/login.html.twig

@@ -40,7 +40,7 @@
 
         <div id="login-help" class="col-sm-7">
             <h3>
-                <i class="fa fa-long-arrow-left" aria-hidden="true"></i>
+                <i class="hidden-xs fa fa-long-arrow-left" aria-hidden="true"></i>
                 {{ 'help.login_users'|trans }}
             </h3>