.external-books { margin-top: 24px; padding-top: 20px; border-top: 1px solid var(--line); }
.external-books-heading h3 { margin: 0 0 8px; font-size: 1.25rem; }
.external-books-heading p, .external-book p { color: var(--muted); font-size: .9rem; margin: 5px 0; }
.external-book { display: flex; align-items: center; justify-content: space-between; gap: 18px; padding: 18px 0; border-bottom: 1px solid var(--line); }
.external-book > div { min-width: 0; }
.external-book h4 { font-size: 1.1rem; margin: 0; overflow-wrap: anywhere; }
.external-book small { color: var(--muted); font-size: .75rem; }
.external-book .button { flex-shrink: 0; font-size: .85rem; }
.external-books-manual { margin: 18px 0 0; font-size: .9rem; }
@media(max-width:600px) { .external-book { align-items: stretch; flex-direction: column; gap: 10px; } .external-book .button { align-self: start; } }