Make the List Item Columns Helper Classes responsive for mobile devices.

ninja-forms-list-item-columns-helper-classes-mobile-responsive.css

/**
* Ninja Forms - List Item Columns Helper Classes Mobile Responsive
* @author Faisal Ahammad
*/

/* ---------------------------------
HELPER CLASSES
----------------------------------*/
.two-col-list ul,
.three-col-list ul,
.four-col-list ul,
.five-col-list ul,
.six-col-list ul {
    display: flex;
    flex-wrap: wrap;
    padding: 0;
    margin: 0;
    list-style: none;
}

.two-col-list li,
.three-col-list li,
.four-col-list li,
.five-col-list li,
.six-col-list li {
    width: 100% !important;
}

/** multiple columns for tablet and desktop **/
@media (min-width: 768px) {
    .two-col-list li {
        width: 50% !important;
    }
    
    .three-col-list li {
        width: 33.33% !important;
    }
    
    .four-col-list li {
        width: 25% !important;
    }
    
    .five-col-list li {
        width: 20% !important;
    }
    
    .six-col-list li {
        width: 16.66% !important;
    }
}