* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    height: 100dvh;
    width: 100%;
    font-family: sans-serif;
    padding: 0;
    margin: 0;
}

main {
    margin: 0 40px;
    padding-bottom: 60px;
}

body > header {
    height: 40px;
    width: 100%;
    background-color: black;
    padding: 0 40px;
    margin-bottom: 20px;
    border-bottom: 3px inset grey;
    overflow: hidden;
}

header nav {
    width: 100%;
}

header nav ul {
    display: flex;
    flex-direction: row;
    height: 100%;
    width: 100%;
    align-items: center;
    justify-content: flex-start;
}

header nav li {
    list-style-type: none;
}

header nav li:not(:first-child) {
    margin-left: 20px;
}

header nav a {
    background-image: radial-gradient(white, white);
    background-clip: text;
    color: white;
    font-size: 1.3rem;
    font-weight: 600;
    text-decoration: none;
    transition: all .7s ease;
}

header nav a.current {
    color: yellow;
}

header nav a:hover {
    background-image: radial-gradient(white, red);
    color: transparent;
    transition: all .7s ease;
    animation: alternate move-mask 20s linear infinite;
}

header nav a.current:hover {
    background-image: radial-gradient(yellow, red);
}

@keyframes move-mask {
    from { background-position: 0 0; }
    to { background-position: 0 200px; }
}