Push right only on mobile

[fortm]

LOGO needs to be centered on Mobile view taking entire row
And left floated when in large display with rest of columns.
But I am unable to do so using bare simplegrid classes..

       <div class="grid">                   
                <div class="col-3-12 mobile-col-1-1">
                        Logo
                </div>
                <div class="col-9-12 mobile-col-1-1">
                    <ul>
                        <li class="push-right mobile-col-1-2">
                            RIGHT HEADER 1
                        </li>
                        <li class="push-right mobile-col-1-2">
                            RIGHT HEADER 2
                        </li>
                    </ul>
                </div>                                      
       </div>