header.css

:root {
    --top-nav-color: #fff;
    --top-nav-background-color: transparent;
    --top-caption-color: #ccc;
    --scroll-nav-color: #fff;
    --scroll-nav-background-color: #000000;
    --scroll-caption-color: #ccc;
}

header {
    width: 100%;
    height: 100vh;
    color: #fff;
    position: relative;
    text-align: center;
    z-index: 0;
    background-color: #000;
    display: flex;
    justify-content: center;
    flex-direction: column;
    overflow: hidden;
}

header img {
    width: 100%;
}

header nav {
    top: 0;
    left: 0;
    display: flex;
    flex-direction: column;
    position: fixed;
    width: 100%;
    height: 100vh;
    transition-property: background-color, box-shadow;
    transition-duration: 500ms;
    background-color: var(--top-nav-background-color);
    color: var(--top-nav-color);
}

header nav .caption {
    text-align: center;
}

header nav h1 {
    text-align: center;
    font-size: 60px;
    white-space: nowrap;
}

header nav .caption {
    color: var(--top-caption-color);
}

header nav .caption,
header nav h1 {
    transition-property: color, font-size;
    transition-duration: 500ms;
    margin: 20px 0;
}

header nav .title {
    flex-direction: column;
    display: flex;
    margin: auto 0;
}

header nav .title .scroller {
    margin: 0 calc(50% - 15.5px);
    position: absolute;
    bottom: 20px;
    font-size: 9px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-decoration: none;
    color: inherit;
    justify-content: center;
}

header nav .title .scroller:hover {
    transition: bottom 1000ms;
    bottom: 10px;
}

header nav .title .scroller:hover .material-symbols-outlined {
    transition: margin-top 1000ms;
    margin-top: 10px;
}

header nav ul {
    margin: 0;
    padding: 0;
    text-align: center;
    overflow: hidden;
    transition: max-height 1000ms;
    position: relative;
}

header nav ul li.left {
    position: absolute;
    left: 0;
    padding: 20px;
}

header nav.scroll {
    height: initial;
    background-color: var(--scroll-nav-background-color);
    box-shadow: 0 10px 4em 0px var(--scroll-nav-color);
    color: var(--scroll-nav-color);
    box-shadow: none;
}

header nav.scroll .title {
    flex-direction: row;
}

header nav.scroll .title .scroller {
    display: none;
}

header nav.scroll h1 {
    font-size: 20px;
    margin: 10px;
}

header nav.scroll .caption {
    font-size: 15px;
    margin: 12.5px;
    color: var(--scroll-caption-color);
}

header nav ul li {
    display: inline-block;
    padding: 20px 40px;
}

header nav ul li a {
    display: flex;
    justify-content: center;
    text-decoration: none;
    color: inherit;
    font-size: 20px;
    transition: color 500ms;
}

header nav ul li a:hover {
    color: #ccc;
}

header nav ul li a span {
    margin: 0 5px;
}

header nav .logo {
    position: fixed;
    float: left;
    color: #fff;
    width: 44px;
    height: 44px;
    padding: 10px;
}

header nav .logo .account {
    z-index: 99;
    -webkit-font-smoothing: antialiased;
    color: #fff;
    -webkit-tap-highlight-color: transparent;
    border-radius: 8px;
    box-shadow: 0px 1px 2px 0px rgba(60, 64, 67, .30), 0px 2px 6px 2px rgba(60, 64, 67, .15);
    height: 300px;
    overflow-x: hidden;
    position: fixed;
    width: 200px;
    background: #000;
}

header nav .logo .account table {
    text-align: center;
    width: 100%;
}

header nav .logo .account table tr {
    display: flex;
}

header nav .logo .account table tr td {
    width: 100%;
}

header nav .logo .account table .logout {
    text-decoration: none;
    border: 1px solid #ccc;
    border-radius: 8px;
    color: #fff;
    padding: 5px 15px;
    display: block;
    margin: 15px 0;
}

header nav .hamburg {
    display: none;
    float: right;
}

header nav .hamburg span {
    margin: 10px;
    padding: 10px;
    cursor: pointer;
    border-radius: 50%;
}

@media(max-width: 800px) {
    header nav .hamburg {
        display: initial;
    }

    header nav ul {
        max-height: 0;
    }

    header nav ul.show {
        max-height: 424px;
    }

    header nav ul li {
        width: 100%;
        padding: 24px 0;
    }

    header nav ul li.left {
        position: initial;
        padding: 20px 40px;
    }
}