/* 古籍页面沿用全站字体、朱红色与白色内容卡片。 */
.books-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 24px 24px 48px;
}
.book-heading { margin-bottom: 24px; }
.book-heading h1 {
    font-family: var(--font-serif);
    font-size: 28px;
    font-weight: 600;
    line-height: 1.5;
    margin: 0 0 8px;
}
.book-heading p { line-height: 1.9; }
.books-page-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; margin-bottom: 20px; }
.books-page-heading h1 { font-size: 24px; }
.book-meta, .books-total { font-size: 14px; color: #737373; }
.books-total { white-space: nowrap; }
.books-total strong { font-weight: 500; color: var(--color-accent); }
.book-description { margin-top: 16px; max-width: 800px; font-size: 15px; color: var(--color-text-light); }
.book-categories {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 4px;
    padding: 12px 16px;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: 8px;
}
.book-categories a { padding: 6px 10px; border-radius: 4px; font-size: 14px; }
.book-category-root { font-weight: 500; }
.book-category-child { color: var(--color-text-light); }
.book-categories a[aria-current] { color: #fff; background: var(--color-accent); }
.book-tools button {
    padding: 8px 16px;
    font: inherit;
    color: var(--color-text-light);
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 4px;
    cursor: pointer;
}
.book-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 20px; }
.book-card { display: flex; flex-direction: column; padding: 24px; background: #fff; border: 1px solid var(--color-border); border-radius: 8px; }
.book-card:hover { border-color: rgba(192, 72, 81, .3); }
.book-card h2 { margin: 0 0 8px; font-family: var(--font-serif); font-size: 20px; line-height: 1.5; font-weight: 600; }
.book-card-description { margin: 12px 0 16px; font-size: 14px; line-height: 1.9; color: var(--color-text-light); }
.book-enter { margin-top: auto; font-size: 13px; color: var(--color-accent); align-self: flex-start; }
.book-source { margin: 20px 0; font-size: 13px; color: #737373; line-height: 1.9; overflow-wrap: anywhere; }
.book-source summary { cursor: pointer; }
.book-source p { margin-top: 8px; white-space: pre-line; }
.book-source a { color: var(--color-accent); }
.book-directory { padding: 24px 32px; background: #fff; border: 1px solid var(--color-border); border-radius: 8px; }
.book-directory h2 { font-family: var(--font-serif); font-size: 20px; font-weight: 600; margin-bottom: 16px; }
.book-directory h3 { margin: 24px 0 8px; padding-left: 12px; border-left: 3px solid var(--color-accent); font-family: var(--font-serif); font-size: 17px; font-weight: 600; }
.book-directory p a { display: block; padding: 12px 0; border-bottom: 1px solid var(--color-border); font-size: 15px; }
.book-directory p:last-child a { border-bottom: 0; }
.book-pagination { display: flex; align-items: center; justify-content: center; gap: 20px; padding: 24px 0; font-size: 14px; }
.book-pagination a { padding: 8px 16px; border: 1px solid #ddd; border-radius: 4px; background: #fff; }
.book-pagination span { color: #737373; }
.book-empty { padding: 40px 16px; text-align: center; font-size: 14px; color: #737373; }
.book-reading-layout { max-width: 1000px; padding: 16px 24px 48px; display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 16px; align-items: start; }
.book-reading-layout > .breadcrumb { grid-column: 1 / -1; }
.book-reading { min-width: 0; padding: 24px; background: #fff; border-radius: 6px; box-shadow: 0 1px 3px rgba(0, 0, 0, .04); }
.book-reading-heading { text-align: center; padding-bottom: 16px; margin-bottom: 20px; border-bottom: 1px solid var(--color-border); }
.book-reading-heading h1 { margin-bottom: 8px; font-size: 26px; font-weight: 700; letter-spacing: .08em; overflow-wrap: anywhere; }
.book-reading-byline { display: flex; flex-wrap: wrap; justify-content: center; align-items: baseline; gap: 4px 12px; font-size: 13px; color: #777; }
.book-reading-byline a { color: #004B50; }
.book-reading-byline span { padding-left: 12px; border-left: 1px solid var(--color-border); }
.book-reading-aside { position: sticky; top: 80px; min-width: 0; padding: 20px 16px; background: #fff; border-radius: 6px; box-shadow: 0 1px 3px rgba(0, 0, 0, .04); font-size: 14px; line-height: 1.9; overflow-wrap: anywhere; }
.book-reading-aside h2 { padding-left: 8px; border-left: 3px solid var(--color-accent); font-family: var(--font-serif); font-size: 16px; font-weight: 600; line-height: 1.2; margin-bottom: 20px; }
.book-reading-book { display: block; text-align: center; font-family: var(--font-serif); font-size: 20px; font-weight: 600; }
.book-reading-attribution { margin: 4px 0 16px; color: #777; font-size: 13px; text-align: center; }
.book-reading-neighbours { margin-top: 16px; }
.book-reading-neighbours > :is(a, p) { display: block; margin: 0; padding: 12px 8px; border-top: 1px solid var(--color-border); }
.book-nav-label { display: block; color: #777; font-size: 12px; font-family: var(--font-sans); line-height: 1.6; }
.book-nav-title { display: block; margin-top: 4px; font-family: var(--font-serif); font-size: 16px; line-height: 1.7; overflow-wrap: anywhere; }
.book-reading-current { background: var(--color-bg); }
.book-reading-current .book-nav-title { color: var(--color-accent); }
.book-reading-directory { display: block; margin-top: 16px; padding: 8px; border-top: 1px solid var(--color-border); text-align: center; font-size: 13px; color: #004B50; }
.book-tools { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; align-items: center; margin: 16px 0 0; font-size: 13px; }
.book-tools button { padding: 6px 12px; border-color: var(--color-border); }
.book-tools button:hover { color: var(--color-accent); border-color: var(--color-accent); }
#book-copy-status { font-size: 12px; color: #004B50; }
#book-copy-status:empty { display: none; }
.book-tools[hidden] { display: none; }
.book-reading-quick-nav { display: none; }
.book-text { font-family: var(--font-serif); font-size: 18px; line-height: 2; overflow-wrap: anywhere; }
.book-paragraph { white-space: pre-wrap; margin-bottom: 24px; }
.book-commentary { display: inline-block; margin-bottom: 24px; font-family: var(--font-sans); font-size: 13px; color: var(--color-accent); }
.book-chapter-nav { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: center; gap: 16px; padding-top: 16px; border-top: 1px solid var(--color-border); font-size: 14px; }
.book-chapter-nav > :is(a, span) { min-width: 0; padding: 8px 0; }
.book-chapter-next { text-align: right; }
.book-chapter-directory { color: #004B50; }
.book-nav-boundary { color: #777; font-size: 13px; }
.poem-book-links { border-top: 1px solid var(--color-border); margin: 16px 0; padding-top: 12px; font-size: 14px; line-height: 1.8; }
.books-container a:hover, .poem-book-links a:hover { color: var(--color-accent); }
.book-categories a[aria-current]:hover { color: #fff; }
.books-container :is(a, button, input):focus-visible, .poem-book-links a:focus-visible { outline: 2px solid var(--color-accent); outline-offset: 3px; }
@media (max-width: 768px) {
    .books-container.book-reading-layout { padding: 12px 16px 32px; grid-template-columns: minmax(0, 1fr); }
    .book-reading-aside { display: none; }
    .book-reading-quick-nav { display: flex; align-items: center; justify-content: center; gap: 24px; margin-top: 12px; font-size: 13px; }
    .book-reading-quick-nav > :is(a, span) { display: inline-flex; align-items: center; min-height: 44px; }
    .book-reading-quick-nav a { color: #004B50; }
    .book-reading-quick-nav span { color: #777; }
}
@media (max-width: 640px) {
    .books-container { padding: 16px 16px 32px; }
    .book-heading h1 { font-size: 24px; }
    .books-page-heading { gap: 8px; }
    .books-total { font-size: 13px; }
    .book-grid { grid-template-columns: minmax(0, 1fr); gap: 16px; }
    .book-card { padding: 20px; }
    .book-card h2 { font-size: 18px; }
    .book-categories { padding: 8px; }
    .book-categories a { min-height: 44px; display: inline-flex; align-items: center; }
    .book-tools button { min-height: 44px; }
    .book-directory { padding: 20px; }
    .book-reading { padding: 20px 16px; }
    .book-reading-heading h1 { font-size: 24px; }
    .book-text { font-size: 18px; line-height: 2; }
}

/* 主分类和细分类分层显示。 */
.book-filters { margin-bottom: 20px; padding: 12px 20px; border: 1px solid var(--color-border); border-radius: 8px; background: #fff; }
.book-filters .book-categories { display: block; padding: 0; border: 0; border-radius: 0; }
.book-filter-row { display: flex; gap: 16px; align-items: baseline; padding: 6px 0; }
.book-filter-label { flex: 0 0 42px; font-size: 13px; color: #737373; }
.book-filter-options { display: flex; flex-wrap: wrap; align-items: center; gap: 4px; min-width: 0; }
.book-filters .book-categories a { display: inline-flex; align-items: center; padding: 4px 12px; min-height: 34px; }
.book-category-group { display: flex; flex-wrap: wrap; align-items: center; gap: 4px; }
.book-category-group + .book-category-group { margin-left: 16px; padding-left: 20px; border-left: 1px solid var(--color-border); }
.book-category-group-label { font-size: 12px; color: #999; padding-right: 4px; }
.book-search-result { margin-bottom: 16px; font-size: 14px; color: var(--color-text-light); }
/* 书籍资料保持紧凑；长目录采用分组网格，减少逐行翻阅。 */
.book-overview { margin-bottom: 20px; padding: 24px 28px; border: 1px solid var(--color-border); border-radius: 8px; background: #fff; }
.book-overview .book-heading { margin-bottom: 0; }
.book-overview .book-heading h1 { margin-bottom: 6px; }
.book-overview .book-description { margin-top: 12px; font-size: 14px; }
.book-overview .book-source { margin: 12px 0 0; }
.book-detail .book-directory { padding: 24px 28px; }
.book-directory-heading { display: flex; justify-content: space-between; align-items: center; margin-bottom: 16px; padding-bottom: 14px; border-bottom: 1px solid var(--color-border); }
.book-directory-heading h2 { margin: 0; }
.book-directory-heading span { font-size: 13px; color: #737373; }
.book-directory-list { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); column-gap: 28px; }
.book-directory-list h3 { grid-column: 1 / -1; margin: 20px 0 8px; }
.book-directory-list h3:first-child { margin-top: 0; }
.book-directory-list p { min-width: 0; }
.book-directory-list p a { padding: 10px 0; overflow-wrap: anywhere; }
@media (max-width: 900px) { .book-directory-list { grid-template-columns: repeat(2, minmax(0, 1fr)); } }
@media (max-width: 640px) {
    .book-filters { padding: 12px 16px; }
    .book-filter-row { gap: 8px; }
    .book-filter-label { flex-basis: 32px; }
    .book-filters .book-categories a { min-height: 44px; padding: 6px 10px; }
    .book-subcategories { display: block; }
    .book-category-group + .book-category-group { margin-left: 0; padding-left: 0; border-left: 0; }
    .book-overview, .book-detail .book-directory { padding: 20px; }
    .book-directory-list { grid-template-columns: minmax(0, 1fr); }
}

/* 完整的经史子集字典，每部一行。 */
.book-filters .book-classification-row { align-items: flex-start; border-top: 1px dashed var(--color-border); padding: 8px 0; }
.book-filters .book-classification-row > .book-filter-label { flex: 0 0 42px; padding: 5px 0; min-height: 34px; color: var(--color-text); font-size: 14px; font-weight: 600; }
.book-filters .book-classification-row > .book-filter-label[aria-current] { padding-left: 7px; color: #fff; }
.book-filters .book-classification-row .book-filter-options { flex: 1; gap: 2px 4px; }
.book-filters .book-classification-row .book-filter-options a { padding: 4px 9px; }
.book-filters .book-filter-all { padding-bottom: 10px; }
.book-empty a { color: var(--color-accent); }
@media (max-width: 640px) {
    .book-filters .book-classification-row > .book-filter-label { flex-basis: 42px; min-height: 44px; padding-top: 10px; }
    .book-filters .book-classification-row .book-filter-options a { min-height: 44px; padding: 6px 8px; }
}

/* 古籍独立书卷样式：实体封面、书籍资料、平铺目录。 */
.book-detail, .books-directory { max-width: 1120px; }
.books-directory .book-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0 40px; }
.book-card-info { display: flex; flex-direction: column; min-width: 0; }
.books-directory .book-card {
    padding: 28px 0;
    border: 0;
    border-bottom: 1px solid #e5e5e3;
    border-radius: 0;
    background: transparent;
}
.book-card.has-cover { display: grid; grid-template-columns: 140px minmax(0, 1fr); gap: 24px; align-items: center; }
.book-card-cover-link { display: block; }
.book-cover { position: relative; isolation: isolate; width: 100%; aspect-ratio: 3 / 4; container-type: inline-size; }
.book-cover-base { display: block; width: 100%; height: auto; }
.book-cover-art {
    position: absolute;
    left: 7.2%;
    top: 10%;
    width: 79%;
    height: 84.5%;
    object-fit: cover;
    mix-blend-mode: multiply;
    /* Feather the real illustration into the shared paper, keeping its centre sharp. */
    -webkit-mask-image: linear-gradient(to bottom, transparent, #000 14%, #000 84%, transparent), linear-gradient(to right, transparent, #000 3%, #000 96%, transparent);
    mask-image: linear-gradient(to bottom, transparent, #000 14%, #000 84%, transparent), linear-gradient(to right, transparent, #000 3%, #000 96%, transparent);
    -webkit-mask-composite: source-in;
    mask-composite: intersect;
    clip-path: polygon(28% 0, 100% 0, 100% 100%, 0 100%, 0 61%, 28% 61%);
}
.book-cover-title {
    position: absolute;
    left: 11.9%;
    top: 14.2%;
    width: 15.5%;
    height: 44%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: var(--font-serif);
    font-size: 24px;
    font-size: calc(10cqw * var(--book-title-scale, 1));
    font-weight: 600;
    line-height: 1;
    letter-spacing: .15em;
    color: #27251f;
    writing-mode: vertical-rl;
    text-orientation: upright;
    white-space: nowrap;
}
.book-cover-fallback { display: block; width: 100%; height: 100%; object-fit: contain; }
.book-card.has-cover .book-meta { font-size: 13px; }
.book-card.has-cover .book-card-description { margin: 12px 0 16px; }
.book-card h2 { font-size: 22px; }
.book-overview {
    margin: 0;
    padding: 0 32px 28px;
    border: 0;
    border-radius: 0;
    background: transparent;
}
.book-overview.has-cover { display: grid; grid-template-columns: 270px minmax(0, 1fr); gap: 72px; align-items: center; }
.book-cover--detail { display: block; }
.book-overview-info { min-width: 0; align-self: end; padding-bottom: 12px; }
.book-overview .book-heading h1 { margin: 0; font-size: 48px; font-weight: 500; line-height: 1.4; letter-spacing: .04em; }
.book-overview .book-meta { margin-top: 18px; font-family: var(--font-serif); font-size: 18px; }
.book-overview .book-description { margin-top: 24px; font-family: var(--font-serif); font-size: 18px; line-height: 1.9; }
.book-overview .book-source { margin: 24px 0 0; font-family: var(--font-serif); font-size: 15px; }
.book-start-reading { display: inline-flex; align-items: center; gap: 16px; margin-top: 28px; padding-bottom: 4px; border-bottom: 1px solid var(--color-accent); color: var(--color-accent); font-family: var(--font-serif); font-size: 17px; }
.book-start-reading img { display: block; }
.book-detail .book-directory { padding: 26px 0 0; border: 0; border-top: 1px solid #d7d7d4; border-radius: 0; background: transparent; }
.book-directory-heading { padding-bottom: 18px; margin-bottom: 0; border-bottom: 0; }
.book-directory-heading h2 { font-size: 30px; font-weight: 500; }
.book-directory-list { display: block; }
.book-directory-group + .book-directory-group { margin-top: 24px; }
.book-directory-entries { columns: 3; column-gap: 24px; }
.book-directory-entries p { break-inside: avoid; }
.book-directory-list p a { padding: 10px 0; font-family: var(--font-serif); font-size: 18px; line-height: 1.7; border-bottom: 1px solid #e5e5e3; }
.book-directory-list p:last-child a { border-bottom: 1px solid #e5e5e3; }
@media (max-width: 900px) {
    .book-overview.has-cover { grid-template-columns: 200px minmax(0, 1fr); gap: 40px; padding: 20px 8px 32px; }
    .book-overview .book-heading h1 { font-size: 38px; }
    .book-directory-entries { columns: 2; }
    .books-directory .book-grid { gap: 0 24px; }
    .book-card.has-cover { grid-template-columns: 110px minmax(0, 1fr); gap: 18px; }
}
@media (max-width: 640px) {
    .books-directory .book-grid { grid-template-columns: minmax(0, 1fr); }
    .books-directory .book-card { padding: 24px 0; }
    .book-card h2 { font-size: 20px; }
    .book-overview { padding: 12px 4px 28px; }
    .book-overview.has-cover { grid-template-columns: minmax(0, 1fr); gap: 24px; padding: 12px 4px 28px; }
    .book-overview-info { align-self: auto; padding-bottom: 0; }
    .book-cover--detail { width: 160px; margin: 0 auto; }
    .book-overview .book-heading h1 { font-size: 30px; }
    .book-overview .book-meta { margin-top: 10px; font-size: 14px; }
    .book-overview .book-description { margin-top: 14px; font-size: 14px; }
    .book-overview .book-source { margin-top: 14px; font-size: 13px; }
    .book-start-reading { margin-top: 18px; font-size: 15px; }
    .book-detail .book-directory { padding: 20px 4px 0; }
    .book-directory-heading { padding-bottom: 12px; }
    .book-directory-heading h2 { font-size: 24px; }
    .book-directory-list p a { font-size: 16px; }
    .book-directory-entries { columns: 1; }
}