.nav_bar {
    list-style: none;
    display: flex;
    gap: 30px;
}

.nav_bar a {
    position: relative;
    text-decoration: none;
    /* color: black; */
    /* font-size: 18px; */
}

.nav_bar a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -5px;
    width: 0;
    height: 2px;
    background-color: black;
    transition: width 0.5s ease;
}

.nav_bar a:hover::after {
    width: 100%;
}