.back {
    margin: 16px 0;
}
.back a {
    color: #3366cc;
    font-size: 14px;
}
h1 {
    margin: 8px 0 24px 0;
    color: #222;
}
h2 {
    margin: 20px 0 8px 0;
    font-size: 1.1em;
    color: #444;
}
main ul {
    list-style: none;
    padding: 0;
    margin: 0 0 16px 0;
}
main li {
    margin: 6px 0;
    line-height: 1.6;
}
main li a {
    color: #3366cc;
}.chapter-nav {
    display: flex;
    justify-content: space-between;
    margin: 24px 0 0 0;
    padding: 12px 0;
    border-top: 1px solid #eee;
    font-size: 14px;
}
.chapter-nav a {
    color: #3366cc;
}