tissue/resources/assets/sass/_underline-tabs.scss

.tis-nav-underline-tabs {
    margin-bottom: -1px;

    .nav-link {
        padding: 0.5rem 1.25rem;
        color: $secondary;
        border-bottom: 2px solid transparent;
        transition: border-bottom-color .12s ease-in;

        @include media-breakpoint-up(lg) {
            padding: 1rem 1.25rem;
        }

        &.active {
            color: $primary;
            border-bottom-color: $primary;
        }

        &:not(.active):hover {
            border-bottom-color: transparentize($secondary, 0.3);
            transition: border-bottom-color .4s ease-out;
        }
    }
}