kanban_view_mobile.scss

@include media-breakpoint-down(sm) {
    .o_kanban_view.o_kanban_grouped {
        display: block;
        position: relative;
        overflow: hidden;

        .o_kanban_mobile_tabs {
            height: $o-kanban-mobile-tabs-height;
            position: relative;
            background-color: #5E5E5E;

            .o_kanban_mobile_tab {
                @include o-position-absolute($left: 100%);
                transform: translateX(-50%);
                height: $o-kanban-mobile-tabs-height;
                padding: 10px;
                font-size: 14px;
                color: white;

                &.o_current {
                    font-weight: bold;
                    border-bottom: 3px solid $o-brand-primary;
                }
                .o_column_title {
                    white-space: nowrap;
                }
            }
        }

        // [class] to get same specificity as elsewhere (kanban_view.less)
        &[class] .o_kanban_group:not(.o_column_folded) {
            @include o-position-absolute($top: $o-kanban-mobile-tabs-height, $left: 0, $bottom: 0);
            overflow-x: scroll;
            width: 100%;
            padding: 0;
            margin-left: 0; // override the margin-left: -1px of the desktop mode
            border: none;

            &.o_current {
                position: initial;
            }
            .o_kanban_header {
                display: none;
            }
            .o_kanban_record, .o_kanban_quick_create {
                border: none;
                border-bottom: 1px solid lightgray;
                padding: 10px 16px;
                margin: 0;
            }
        }
    }
}