header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
    color: white;
    padding: 20px;
    z-index: 10;
    background-color: black;
    box-shadow: 0px 1.5px 5px rgba(0, 0, 0, 0.3);
    box-sizing: border-box;
}

header nav {
    margin-bottom: 10px;
    text-align: center;
    position: relative;
}

.nav-links {
    display: flex;
    justify-content: center;
}

header nav a.top-menu {
    display: inline-block;
    /* margin: 0 100px 0 100px; */
    margin: 0 5% 0 5%;
    color: antiquewhite;
    /* color: white; */
    letter-spacing: 1px;
    text-decoration: none;
    font-size: 1.3em;
    transition: color 0.3s;
    /* font-family: SF Pro Display; */
    font-family:system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif
}

header nav a.top-menu:hover {
    color: rgb(164, 164, 164);
}

.hamburger {
    display: none;
    cursor: pointer;
    width: 30px;
    height: 20px;
    position:fixed;
    right: 20px;
    top: 20px;
    flex-direction: column;
    justify-content: space-between;
}

.hamburger span {
    display: block;
    height: 3px;
    width: 100%;
    background-color: antiquewhite;
    transition: all 0.3s ease;
}

@media screen and (max-width: 768px) {

    .hamburger {
        display: flex;
    }

    .nav-links {
        display: none;
        width: 100%;
        flex-direction: column;
        align-items: center;
        padding-top: 20px;
    }

    .nav-links.active {
        display: flex;
    }

    header nav a.top-menu {
        margin: 10px 0;
        font-size: 1.1em;
    }

    .hamburger.active span:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .hamburger.active span:nth-child(2) {
        opacity: 0;
    }

    .hamburger.active span:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
}