* { box-sizing: border-box; }
html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    font-family: Arial, Helvetica, sans-serif;
    background: #0f1117;
    color: #f3f3f3;
}
body { overflow: hidden; }
button { font: inherit; }