* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: sans-serif, monospace;
}
html, body {
    width: 100%;
    height: 100%;
    position: relative;
    background-color: #333;
}
main {
    display: flex;
    width: 100%;
    height: 100%;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

main > h2 {
    text-align: center;
    color: white;
    margin-bottom: 1em;
}

main > section {
    width: 100%;
    max-width: 500px;
    margin: 0 auto;
    display: flex;
    justify-content: space-around;
    color: white;
    font-size: 32px;
    background-color: transparent;
}

main > section > span {
    width: 5em;
}

main > section > button {
    border: 0;
    width: 8em;
    padding: 1em;
    margin-top: 3em;
    background-color: #eee;
    color: #333;
}