venom/public/theme/default/css/test.css

* {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    font-size: 16px;
    color: #fff;
    background-color: #333;
    font-family: sans-serif;
    height: 100vh;
    width: 100vw;
}

header {
    font-size: 5vw;
    cursor: pointer;
}

header:hover {
    color: #ff0323;
}