.nav-link {
    position: relative;
    transition: color .3s ease;
}

/* Línea invisible por defecto */
.nav-link::after {
    content: '';
    position: absolute;
    left: 50%;
    bottom: -10px;
    width: 0;
    height: 3px;
    border-radius: 999px;
    transform: translateX(-50%);
    transition: all .3s ease;
}

/* Hover = dorado */
.nav-link:hover::after {
    width: 100%;
    background-color: #C3953C;
}

/* Página activa = azul */
.nav-link.active {
    color: #001A3F;
}

.nav-link.active::after {
    width: 100%;
    background-color: #001A3F;
}