.book-cover {
    float: right;
    width: 170px;
    margin: 0 0 1.2rem 1.5rem;
    padding: 4px;
    background: #fff;
    border: 1px solid #dee2e6;
    border-radius: 4px;
}

.book-toc h3 {
    margin-top: 2.2rem;
}

.book-toc ul.chapters {
    list-style: none;
    margin: 0;
    padding: 0;
}

.book-toc ul.chapters > li {
    margin-bottom: .6rem;
    line-height: 1.5;
}

.book-toc ul.subs {
    list-style: none;
    display: inline;
    margin: 0;
    padding: 0 0 0 .4rem;
    color: #6c757d;
    font-size: .93em;
}

.book-toc ul.subs li {
    display: inline;
}

.book-toc ul.subs li::after {
    content: " · ";
    color: #adb5bd;
}

.book-toc ul.subs li:last-child::after {
    content: "";
}

@media (max-width: 576px) {
    .book-cover {
        float: none;
        display: block;
        margin: 0 auto 1.2rem;
    }
}