.contentnav-item:nth-last-child(6):first-child ~ :nth-child(3n+1) {
    clear: none
}
.contentnav-item:nth-last-child(6):first-child ~ :nth-child(4n+1) {
    clear: left
}

@media only screen and (max-width: 1068px) {
    .contentnav-item:first-child:first-child ~ :nth-child(1n) {
        clear: none
    }

    .contentnav-item:first-child:first-child ~ :nth-child(3n+1) {
        clear: left
    }
}

@media only screen and (max-width: 734px) {
    .contentnav-item {
        width: 50%
    }

    .contentnav-item:first-child:first-child ~ :nth-child(1n) {
        clear: none
    }

    .contentnav-item:first-child:first-child ~ :nth-child(2n+1) {
        clear: left
    }
}