body {
    margin: 0 auto;
    max-width: 450px;
    padding: 0 20px 100px 20px;
    font-size: 18px;
    line-height: 1.5;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji",
        "Segoe UI Symbol";
}

h1 {
    line-height: 1.1;
    font-size: 3rem;
    padding-bottom: 2rem;
}

h2 {
    font-size: 2rem;
}

a {
    color: rgb(0, 122, 255);
    text-decoration: none;
}

ol {
    margin: 1.0rem 0 1.5rem 2rem;
    padding: 0;
}

li {
    margin-top: 0.5rem;
}

button, input {
    font-size: 1rem;
}

button {
    padding: 0.2rem 0.5rem;
    border: 1px solid #909090;
    border-radius: 6px;
    background: linear-gradient(#fff, #eee);
    cursor: pointer;
}