.container {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
}
nav ul li {
    text-decoration: none;
    font-weight: 600;
    color: black;
    position: relative;
}

nav ul li::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0%;  /* Start with 0% width */
    height: 2px;  /* The thickness of the bottom border */
    background-color: black;  /* Color of the bottom border */
    transition: width 0.3s ease;  /* Animation to transition the width */
}

nav ul li:hover::after {
    width: 100%;  /* On hover, expand to 100% width */
}
html {
  scroll-padding-top: 70px; /* height of your fixed navbar */
}