.custom-multiProductCustomProduct #multiProductCustomProduct{
    display: flex;

    li input{
        width: 100%;
    }

    li:first-child{
        flex-basis: 100%;
    }

    li:not(:first-child){
        flex-basis: 50%;
    }

    @media screen and (max-width: 340px) {
        li:not(:first-child){
            flex-basis: 100%;
        }
    }
}