.leftGroup {
        float: left;
        width: 48%;
        
    }  
    .rightGroup {
        float: right;
        width: 48%; 
        
    }

#group {
}
    :after.group {
        content:"";
        display: table;
        clear: both;
    }
    @media screen and (max-width: 640px) {
        .leftGroup, .rightGroup {
            float: none;
            width: auto;
        }
    }
}