* {
    box-sizing: border-box;
}

body {
    margin: 0;
    min-height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;

    font-family: Arial, sans-serif;
    background: #111;
    color: white;
}

main {
    width: 90%;
    max-width: 500px;
    text-align: center;
}

h1 {
    font-size: 3rem;
}