.wrap{display:table;width:100%;max-width:900px;margin:0 auto;}
.half{display:table-cell;width:50%;vertical-align:middle;background:#f4f4f4;border:2px solid #ffffff;padding:30px 0px;text-align:center;box-sizing:border-box;}

@media all and (max-width: 768px)
{
.half{display:block;width:100%;}
}