Navigation hover effect for Kester template

Add to Home > Design > Custom CSS

.header-nav-item--active a {
    background-image: none !important;
}
.header-nav-item a:hover {
    background-repeat: repeat-x;
    background-image: linear-gradient(to right,currentColor 100%,currentColor 0) !important;
    background-size: 1px 1px;
    background-position: 0 calc(100% - 0.1em) !important;
    white-space: initial;
}