:root {
  --blue-950: #08275c;
  --blue-900: #0b3472;
  --blue-800: #0f4b94;
  --blue-700: #1265b3;
  --blue-600: #1877d5;
  --blue-100: #e8f2ff;
  --blue-050: #f5f9ff;
  --ink: #102033;
  --muted: #617189;
  --line: #d8e5f5;
  --white: #ffffff;
  --gold: #d4a842;
  --shadow: 0 18px 48px rgba(8, 39, 92, 0.14);
  --radius: 8px;
}

* {
  box-sizing: border-box;
}

html {
  overflow-x: auto;
  scroll-behavior: smooth;
}

body {
  min-width: 1160px;
  margin: 0;
  color: var(--ink);
  font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", Arial, sans-serif;
  line-height: 1.7;
  overflow-x: auto;
  background: var(--white);
}

a {
  color: inherit;
  text-decoration: none;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  gap: 24px;
  min-height: 72px;
  padding: 10px clamp(18px, 4vw, 56px);
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  min-width: 290px;
}

.brand-mark {
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  color: var(--white);
  font-size: 22px;
  font-weight: 800;
  background: linear-gradient(145deg, var(--blue-900), var(--blue-600));
  border-radius: 8px;
  box-shadow: 0 10px 28px rgba(18, 101, 179, 0.24);
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 17px;
  color: var(--blue-950);
  line-height: 1.25;
}

.brand small {
  margin-top: 2px;
  color: var(--muted);
  font-size: 12px;
}

.main-nav {
  display: flex;
  flex: 1;
  justify-content: flex-end;
  gap: 4px;
  overflow-x: auto;
  white-space: nowrap;
}

.main-nav a {
  padding: 8px 11px;
  color: #29405d;
  font-size: 14px;
  border-radius: 8px;
  transition: 0.2s ease;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--white);
  background: var(--blue-800);
}

.nav-toggle {
  display: none;
}

.section {
  scroll-margin-top: 86px;
  padding: clamp(64px, 8vw, 110px) clamp(20px, 5vw, 76px);
}

.hero {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(260px, 390px);
  gap: 36px;
  align-items: end;
  min-height: calc(100vh - 72px);
  padding: clamp(72px, 8vw, 112px) clamp(20px, 5vw, 76px);
  overflow: hidden;
  color: var(--ink);
  background: var(--white);
  border-bottom: 1px solid var(--line);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 82% 18%, rgba(24, 119, 213, 0.09), transparent 31%),
    linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
}

.hero::after {
  content: none;
}

.hero-content,
.hero-panel {
  position: relative;
  z-index: 1;
}

.hero-content {
  max-width: 860px;
  padding-bottom: 7vh;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--gold);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 900px;
  margin-bottom: 22px;
  font-size: clamp(42px, 7vw, 76px);
  line-height: 1.08;
  letter-spacing: 0;
}

h2 {
  color: var(--blue-950);
  font-size: clamp(28px, 4vw, 46px);
  line-height: 1.18;
  letter-spacing: 0;
}

h3 {
  margin-bottom: 10px;
  color: var(--blue-900);
  font-size: 20px;
}

.hero-lead {
  max-width: 760px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 10px 20px;
  font-weight: 700;
  border: 1px solid rgba(255, 255, 255, 0.36);
  border-radius: 8px;
}

.button.primary {
  color: var(--white);
  background: var(--blue-800);
  border-color: var(--blue-800);
}

.button.secondary {
  color: var(--blue-800);
  background: var(--white);
  border-color: var(--line);
}

.hero-panel {
  margin-bottom: 7vh;
  padding: 28px;
  color: var(--blue-950);
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(255, 255, 255, 0.66);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.hero-panel span,
.hero-panel strong {
  display: block;
}

.hero-panel span {
  color: var(--blue-700);
  font-weight: 800;
}

.hero-panel strong {
  margin: 8px 0;
  font-size: 30px;
  line-height: 1.15;
}

.teacher,
.module {
  max-width: 1280px;
  margin: 0 auto;
}

.home-hero {
  grid-template-columns: minmax(0, 1fr);
  place-items: center;
  min-height: 78vh;
}

.home-hero .hero-bg {
  inset: -10px;
  background:
    linear-gradient(rgba(255, 255, 255, 0.48), rgba(248, 251, 255, 0.58)),
    url("assets/materials/蔡自兴图书网站 6：文献检索/4 GoogleScholar他引200篇检索 202603/Screenshot 2026-03-21 at 7.33.44__PM.png") center / cover no-repeat;
  filter: blur(3px);
  transform: scale(1.02);
}

.home-hero .hero-content {
  width: 100%;
  margin: 0 auto;
  padding-bottom: 0;
  text-align: center;
}

.home-hero .hero-content h1,
.home-hero .hero-lead {
  margin-right: auto;
  margin-left: auto;
}

.home-hero .hero-actions {
  justify-content: center;
}

.page-shell {
  display: block;
  max-width: 1180px;
  margin: 0 auto;
}

.page-main {
  width: 100%;
  min-width: 0;
  margin: 0 auto;
}

.page-title {
  color: var(--blue-950);
  font-size: clamp(30px, 4vw, 48px);
}

.teacher-sidebar {
  position: sticky;
  top: 96px;
  padding: 26px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.teacher-sidebar h2 {
  font-size: 26px;
}

.teacher-sidebar p {
  color: var(--muted);
}

.mini-stats {
  display: grid;
  gap: 12px;
  margin-top: 20px;
}

.mini-stats span {
  display: block;
  padding: 14px;
  color: #2c4261;
  background: var(--blue-050);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.mini-stats strong {
  display: block;
  color: var(--blue-800);
  font-size: 26px;
  line-height: 1;
}

.module-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  margin-top: 30px;
}

.module-grid a {
  min-height: 156px;
  padding: 22px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 12px 32px rgba(8, 39, 92, 0.08);
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.module-grid a:hover {
  transform: translateY(-3px);
  border-color: var(--blue-600);
}

.module-grid strong,
.module-grid span {
  display: block;
}

.module-grid strong {
  color: var(--blue-950);
  font-size: 20px;
}

.module-grid span {
  margin-top: 10px;
  color: var(--muted);
}

.alt {
  max-width: none;
  background: var(--blue-050);
}

.alt > * {
  max-width: 1280px;
  margin-right: auto;
  margin-left: auto;
}

.section-head {
  max-width: 860px;
}

#overview .section-head {
  margin-right: auto;
  margin-left: auto;
  text-align: center;
}

.section-head p,
.module-intro p {
  color: var(--muted);
  font-size: 17px;
}

.stats-grid,
.resource-grid,
.link-grid,
.quote-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
  margin-top: 34px;
}

.stats-grid div,
.resource-grid article,
.link-grid a,
.feature-card,
.detail-stack article,
.timeline article,
.quote-grid blockquote {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 12px 32px rgba(8, 39, 92, 0.08);
}

.stats-grid div {
  padding: 24px;
}

.stats-grid strong,
.paper-board strong {
  display: block;
  color: var(--blue-800);
  font-size: clamp(52px, 5vw, 64px);
  line-height: 1;
}

.stats-grid span,
.paper-board span {
  display: block;
  margin-top: 10px;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.4;
}

.module-intro {
  max-width: 940px;
  margin: 0 auto 40px;
  text-align: center;
}

.module-intro > .eyebrow {
  margin-bottom: 14px;
  color: var(--blue-800);
  font-size: clamp(22px, 2.4vw, 30px);
  font-weight: 900;
  line-height: 1.25;
}

.content-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(300px, 0.9fr);
  gap: 22px;
}

.feature-card,
.detail-stack article,
.resource-grid article {
  padding: 26px;
}

.detail-stack {
  display: grid;
  gap: 18px;
}

.clean-list {
  padding-left: 20px;
  margin: 0;
  color: #30445f;
}

.clean-list li + li {
  margin-top: 10px;
}

.columns {
  columns: 2;
  column-gap: 36px;
}

.text-link {
  display: inline-flex;
  margin-top: 16px;
  color: var(--blue-700);
  font-weight: 800;
  border-bottom: 2px solid rgba(18, 101, 179, 0.24);
}

.resource-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.courseware-directory {
  padding: clamp(22px, 4vw, 36px);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.courseware-directory-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 20px;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--line);
}

.courseware-directory-head .eyebrow {
  margin-bottom: 8px;
}

.courseware-directory-head h2 {
  margin: 0;
  font-size: clamp(28px, 4vw, 40px);
}

.courseware-directory-head > span {
  flex: 0 0 auto;
  color: var(--muted);
  font-weight: 800;
}

.courseware-catalog {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.courseware-catalog li {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr) minmax(118px, 150px);
  gap: 16px;
  align-items: start;
  min-width: 0;
  padding: 20px;
  background: #f8fbff;
  border: 1px solid #dce9f8;
  border-radius: 10px;
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.courseware-catalog li:hover {
  transform: translateY(-2px);
  border-color: var(--blue-600);
  box-shadow: 0 12px 24px rgba(8, 39, 92, 0.08);
}

.courseware-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  color: var(--white);
  font-size: 17px;
  font-weight: 900;
  background: var(--blue-800);
  border-radius: 8px;
}

.courseware-category {
  display: block;
  margin-bottom: 6px;
  color: var(--blue-700);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0.08em;
}

.courseware-catalog h3 {
  margin: 0;
  color: var(--blue-950);
  font-size: 20px;
  line-height: 1.45;
  overflow-wrap: anywhere;
}

.courseware-catalog p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 14px;
}

.courseware-cover {
  justify-self: end;
  width: min(100%, 150px);
  margin: 0;
  padding: 8px;
  background: var(--white);
  border: 1px solid #dce9f8;
  border-radius: 8px;
}

.courseware-cover img {
  display: block;
  width: 100%;
  aspect-ratio: 0.72;
  object-fit: contain;
  border-radius: 4px;
}

.courseware-catalog > .courseware-item-available {
  grid-column: 1 / -1;
  background: linear-gradient(135deg, #f8fbff 0%, #eef6ff 100%);
  border-color: #bad5f2;
}

.courseware-files {
  margin-top: 18px;
}

.courseware-files summary {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 8px 14px;
  color: var(--white);
  font-weight: 800;
  background: var(--blue-800);
  border-radius: 8px;
  cursor: pointer;
  list-style: none;
}

.courseware-files summary::-webkit-details-marker {
  display: none;
}

.courseware-files summary::after {
  margin-left: 10px;
  content: "＋";
}

.courseware-files[open] summary::after {
  content: "－";
}

.courseware-file-list a {
  min-width: 0;
  padding: 14px 16px;
  color: var(--blue-950);
  background: var(--white);
  border: 1px solid #c9dcf4;
  border-radius: 8px;
  transition: color 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}

.courseware-file-list a:hover {
  color: var(--white);
  background: var(--blue-800);
  border-color: var(--blue-800);
}

.courseware-file-list span {
  margin-top: 4px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.courseware-file-list a:hover span {
  color: rgba(255, 255, 255, 0.78);
}

.courseware-file-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  padding: 0;
  margin: 16px 0 0;
  list-style: none;
}

.courseware-file-list li {
  display: block;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: 0;
  box-shadow: none;
}

.courseware-file-list li:hover {
  transform: none;
  border-color: transparent;
  box-shadow: none;
}

.courseware-file-list a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  height: 100%;
}

.courseware-file-list strong {
  min-width: 0;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.courseware-file-list span {
  flex: 0 0 auto;
  margin-top: 0;
}

.link-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.link-grid a {
  position: relative;
  min-height: 142px;
  padding: 24px;
  overflow: hidden;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.link-grid a::before {
  position: absolute;
  inset: 0 auto 0 0;
  width: 5px;
  content: "";
  background: var(--blue-700);
}

.link-grid a:hover {
  transform: translateY(-3px);
  border-color: var(--blue-600);
}

.link-grid strong,
.link-grid span {
  display: block;
}

.link-grid strong {
  color: var(--blue-950);
  font-size: 19px;
}

.link-grid span {
  margin-top: 10px;
  color: var(--muted);
}

.video-grid .video-card {
  display: flex;
  flex-direction: column;
  min-height: 0;
  padding: 0;
}

.video-grid .video-card::before {
  display: none;
}

.video-grid-featured {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  align-items: stretch;
}

.video-grid-featured .video-card:first-child {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(280px, 0.75fr);
}

.video-grid-featured .video-card:first-child .video-thumb {
  height: 100%;
  min-height: 260px;
}

.video-grid-featured .video-card:first-child .video-card-body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: clamp(24px, 4vw, 42px);
}

.video-grid-featured .video-card:first-child strong {
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.25;
}

.video-thumb {
  position: relative;
  display: block;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #eef3f7;
  border-bottom: 1px solid var(--line);
}

.video-thumb::after {
  position: absolute;
  right: 14px;
  bottom: 14px;
  width: 42px;
  height: 42px;
  content: "";
  background: rgba(255, 255, 255, 0.92);
  border-radius: 50%;
  box-shadow: 0 10px 26px rgba(8, 39, 92, 0.16);
}

.video-thumb::before {
  position: absolute;
  right: 27px;
  bottom: 25px;
  z-index: 1;
  width: 0;
  height: 0;
  content: "";
  border-top: 10px solid transparent;
  border-bottom: 10px solid transparent;
  border-left: 15px solid var(--blue-700);
}

.video-thumb img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 0.25s ease;
}

.video-card:hover .video-thumb img {
  transform: scale(1.035);
}

.video-card-body {
  display: block;
  padding: 20px 22px 22px;
}

.link-grid .video-card-body span {
  line-height: 1.7;
}

.video-thumb-empty {
  display: flex;
  align-items: center;
  justify-content: center;
  background:
    linear-gradient(135deg, rgba(11, 61, 145, 0.92), rgba(38, 113, 183, 0.82)),
    #0b3d91;
}

.video-thumb-empty span {
  color: rgba(255, 255, 255, 0.9);
  font-size: 28px;
  font-weight: 700;
  letter-spacing: 0;
}

.module-note {
  margin-top: 20px;
}

.paper-board {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  margin-bottom: 22px;
}

.paper-board div,
.paper-tab {
  padding: 26px;
  color: var(--white);
  background: linear-gradient(145deg, var(--blue-900), var(--blue-700));
  border-radius: var(--radius);
}

.paper-board strong,
.paper-board span {
  color: var(--white);
}

.paper-tab {
  min-height: 136px;
  font: inherit;
  text-align: left;
  border: 1px solid rgba(255, 255, 255, 0.18);
  box-shadow: 0 12px 32px rgba(8, 39, 92, 0.08);
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.paper-tab:hover,
.paper-tab.active {
  transform: translateY(-3px);
  box-shadow: 0 18px 38px rgba(8, 39, 92, 0.16);
  filter: saturate(1.08);
}

.paper-reader {
  padding: clamp(22px, 4vw, 34px);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.paper-content {
  max-height: 68vh;
  padding-right: 12px;
  overflow: auto;
}

.paper-list {
  display: grid;
  gap: 12px;
  padding: 0;
  margin: 0;
  list-style: none;
  counter-reset: paper-entry;
}

.paper-list li {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 18px;
  background: #f8fbff;
  border: 1px solid #dce9f8;
  border-radius: 8px;
  counter-increment: paper-entry;
}

.paper-list li::before {
  color: var(--blue-700);
  font-weight: 900;
  content: counter(paper-entry);
}

.paper-list p {
  margin: 0;
  color: #263b56;
  font-size: 15px;
  line-height: 1.75;
  overflow-wrap: anywhere;
}

.ip-board {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.media-board {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.media-list li {
  align-items: start;
}

.media-entry {
  min-width: 0;
}

.media-entry h3 {
  margin: 0 0 7px;
  color: var(--blue-950);
  font-size: 18px;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.media-entry p {
  margin: 0;
  color: #425670;
  font-size: 15px;
  line-height: 1.75;
}

.media-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.media-links a {
  padding: 7px 11px;
  color: var(--blue-800);
  font-size: 14px;
  font-weight: 800;
  background: var(--white);
  border: 1px solid #c9dcf4;
  border-radius: 7px;
  overflow-wrap: anywhere;
}

.media-links a:hover {
  color: var(--white);
  background: var(--blue-800);
  border-color: var(--blue-800);
}

.media-unavailable {
  display: inline-block;
  margin-top: 11px;
  color: var(--muted);
  font-size: 13px;
}

.ip-summary,
.ip-description {
  color: #3c526d;
  font-size: 15px;
  line-height: 1.8;
}

.ip-summary {
  margin: 0 0 22px;
  padding: 16px 18px;
  background: #f4f8fd;
  border: 1px solid #dce9f8;
  border-radius: 8px;
}

.ip-section + .ip-section {
  margin-top: 28px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}

.ip-section h3 {
  margin: 0 0 10px;
  color: var(--blue-950);
  font-size: 20px;
}

.ip-description {
  margin: 0 0 16px;
}

.ip-list li {
  grid-template-columns: 52px minmax(0, 1fr);
}

.book-overview {
  margin-bottom: 26px;
}

.book-section {
  margin-top: 28px;
}

.book-section-head {
  max-width: 860px;
  margin-bottom: 18px;
}

.book-section-head h2 {
  margin-bottom: 10px;
  font-size: clamp(28px, 4vw, 40px);
}

.book-section-head p:not(.eyebrow) {
  color: var(--muted);
  font-size: 17px;
}

.book-catalog {
  display: grid;
  max-height: 420px;
  gap: 10px;
  padding: 0 12px 0 0;
  margin: 0;
  overflow: auto;
  list-style: none;
  counter-reset: book-catalog;
}

.book-catalog li {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 12px;
  padding: 12px 14px;
  color: #263b56;
  background: #f8fbff;
  border: 1px solid #dce9f8;
  border-radius: 8px;
  counter-increment: book-catalog;
}

.book-catalog li::before {
  color: var(--blue-700);
  font-weight: 900;
  content: counter(book-catalog);
}

.book-reader-shell {
  display: grid;
  grid-template-columns: minmax(220px, 300px) minmax(0, 1fr);
  gap: 22px;
  align-items: start;
}

.book-tabs {
  position: sticky;
  top: 96px;
  display: grid;
  max-height: calc(100vh - 128px);
  gap: 10px;
  padding-right: 6px;
  overflow: auto;
}

.book-tab {
  min-height: 62px;
  padding: 12px 14px;
  color: var(--blue-900);
  font: inherit;
  font-weight: 800;
  line-height: 1.45;
  text-align: left;
  background: var(--white);
  border: 1px solid #c9dcf4;
  border-radius: 8px;
  box-shadow: 0 8px 18px rgba(8, 39, 92, 0.06);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.book-tab:hover {
  transform: translateY(-2px);
  border-color: var(--blue-600);
}

.book-tab.active {
  color: var(--white);
  background: var(--blue-800);
  border-color: var(--blue-800);
}

.book-reader {
  padding: clamp(22px, 4vw, 34px);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.book-detail {
  max-height: 76vh;
  padding-right: 12px;
  overflow: auto;
}

.book-cover-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 220px));
  gap: 18px;
  margin-bottom: 24px;
}

.book-cover {
  margin: 0;
  padding: 12px;
  background: #f8fbff;
  border: 1px solid #dce9f8;
  border-radius: 8px;
}

.book-cover img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 6px;
}

.book-summary {
  display: grid;
  gap: 14px;
  margin-bottom: 24px;
}

.book-summary p {
  margin: 0;
  color: #263b56;
  font-size: 16px;
  line-height: 1.9;
  text-align: justify;
}

.book-contents h3 {
  padding-left: 12px;
  border-left: 4px solid var(--blue-700);
}

.book-contents-list {
  display: grid;
  gap: 10px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.book-content-entry,
.book-chapter-subitem,
.book-section-subitem,
.book-subsection-subitem {
  padding: 9px 12px;
  color: #30445f;
  font-size: 15px;
  line-height: 1.65;
  background: #f8fbff;
  border: 1px solid #dce9f8;
  border-radius: 8px;
  overflow-wrap: anywhere;
}

.book-chapter-item {
  display: grid;
  gap: 8px;
}

.book-section-item {
  display: grid;
  gap: 8px;
}

.book-subsection-item {
  display: grid;
  gap: 8px;
}

.book-chapter-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  padding: 12px 14px;
  color: var(--blue-950);
  font: inherit;
  font-size: 17px;
  font-weight: 900;
  text-align: left;
  background: var(--blue-100);
  border: 1px solid #c9d8e6;
  border-radius: 8px;
  cursor: pointer;
}

.book-section-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  width: 100%;
  padding: 10px 12px;
  color: #24394b;
  font: inherit;
  font-size: 15px;
  font-weight: 800;
  text-align: left;
  background: #f2f5f7;
  border: 1px solid #d7e0e7;
  border-radius: 8px;
  cursor: pointer;
}

.book-subsection-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  width: 100%;
  padding: 9px 12px;
  color: #30445f;
  font: inherit;
  font-size: 15px;
  font-weight: 700;
  text-align: left;
  background: #f8fbff;
  border: 1px solid #dce9f8;
  border-radius: 8px;
  cursor: pointer;
}

.book-chapter-toggle:hover,
.book-chapter-toggle[aria-expanded="true"] {
  color: var(--white);
  background: var(--blue-800);
  border-color: var(--blue-800);
}

.book-section-toggle:hover,
.book-section-toggle[aria-expanded="true"] {
  color: var(--white);
  background: #4f6f8b;
  border-color: #4f6f8b;
}

.book-subsection-toggle:hover,
.book-subsection-toggle[aria-expanded="true"] {
  color: var(--white);
  background: #6c879f;
  border-color: #6c879f;
}

.book-chapter-toggle span:first-child,
.book-section-toggle span:first-child,
.book-subsection-toggle span:first-child {
  min-width: 0;
  overflow-wrap: anywhere;
}

.book-chapter-icon,
.book-section-icon,
.book-subsection-icon {
  display: inline-grid;
  flex: 0 0 auto;
  place-items: center;
  width: 24px;
  height: 24px;
  color: inherit;
  font-size: 20px;
  line-height: 1;
  border: 1px solid currentColor;
  border-radius: 50%;
}

.book-section-icon {
  width: 22px;
  height: 22px;
  font-size: 18px;
}

.book-subsection-icon {
  width: 20px;
  height: 20px;
  font-size: 16px;
}

.book-chapter-items {
  display: none;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 14px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.book-section-items {
  display: none;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 14px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.book-subsection-items {
  display: none;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px 14px;
  padding: 0;
  margin: 0;
  list-style: none;
}

.book-contents-parted .book-chapter-items,
.book-contents-parted .book-section-items,
.book-contents-parted .book-subsection-items {
  grid-template-columns: 1fr;
}

.book-chapter-open .book-chapter-items {
  display: grid;
}

.book-section-open .book-section-items {
  display: grid;
}

.book-subsection-open .book-subsection-items {
  display: grid;
}

.evidence-layout {
  display: grid;
  grid-template-columns: minmax(320px, 0.95fr) minmax(0, 1.05fr);
  gap: 26px;
  align-items: center;
  padding: 22px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.evidence-layout img {
  display: block;
  width: 100%;
  max-height: 380px;
  object-fit: cover;
  object-position: top;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.inline-links,
.attachment-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.timeline {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.timeline article {
  padding: 24px;
  border-top: 4px solid var(--blue-700);
}

.timeline time {
  color: var(--blue-700);
  font-weight: 900;
}

.quote-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.quote-grid blockquote {
  margin: 0;
  padding: 28px;
}

.quote-grid p {
  color: var(--blue-950);
  font-size: 20px;
  font-weight: 700;
}

.quote-grid cite {
  color: var(--muted);
  font-style: normal;
}

.attachment-bar {
  margin-top: 20px;
}

.attachment-bar a {
  padding: 10px 14px;
  color: var(--blue-900);
  font-weight: 800;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.review-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin: 8px 0 22px;
}

.review-tab {
  min-width: 96px;
  min-height: 50px;
  padding: 10px 18px;
  color: var(--blue-900);
  font: inherit;
  font-size: 16px;
  font-weight: 800;
  background: var(--white);
  border: 1px solid #c9dcf4;
  border-radius: 8px;
  box-shadow: 0 8px 18px rgba(8, 39, 92, 0.06);
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.review-tab:hover {
  transform: translateY(-2px);
  border-color: var(--blue-600);
}

.review-tab.active {
  color: var(--white);
  background: var(--blue-800);
  border-color: var(--blue-800);
}

.review-reader {
  padding: clamp(22px, 4vw, 34px);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.review-reader-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 18px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.review-reader-head h2 {
  margin-bottom: 0;
  font-size: clamp(28px, 4vw, 40px);
}

.review-content {
  max-height: 68vh;
  padding-right: 12px;
  overflow: auto;
  counter-reset: leader-subheading;
}

.review-reader-pdf .review-content {
  max-height: none;
  padding-right: 0;
  overflow: visible;
}

.pdf-reader {
  display: grid;
  gap: 12px;
}

.pdf-reader iframe {
  display: block;
  width: 100%;
  height: min(78vh, 860px);
  min-height: 620px;
  background: #eef4fb;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.review-reader-students .pdf-reader iframe {
  height: min(86vh, 980px);
  min-height: 760px;
}

.pdf-fallback {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.pdf-fallback a {
  color: var(--blue-800);
  font-weight: 800;
}

.retrieval-modules {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  margin-bottom: 24px;
}

.retrieval-module {
  position: relative;
  min-height: 176px;
  padding: 24px;
  overflow: hidden;
  color: var(--white);
  font: inherit;
  text-align: left;
  background: linear-gradient(145deg, var(--blue-950), var(--blue-700));
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: var(--radius);
  box-shadow: 0 12px 32px rgba(8, 39, 92, 0.12);
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.retrieval-module::after {
  position: absolute;
  right: -22px;
  bottom: -42px;
  width: 116px;
  height: 116px;
  content: "";
  background: rgba(255, 255, 255, 0.08);
  border-radius: 50%;
}

.retrieval-module:hover,
.retrieval-module.active {
  transform: translateY(-4px);
  box-shadow: 0 20px 42px rgba(8, 39, 92, 0.2);
  filter: saturate(1.12);
}

.retrieval-module.active {
  outline: 3px solid rgba(56, 150, 235, 0.3);
  outline-offset: 3px;
}

.retrieval-module span,
.retrieval-module strong,
.retrieval-module small {
  position: relative;
  z-index: 1;
  display: block;
}

.retrieval-module span {
  margin-bottom: 24px;
  color: #9fd0ff;
  font-size: 14px;
  font-weight: 900;
  letter-spacing: 0.12em;
}

.retrieval-module strong {
  font-size: 20px;
  line-height: 1.35;
}

.retrieval-module small {
  margin-top: 9px;
  color: rgba(255, 255, 255, 0.72);
  font-size: 14px;
}

.retrieval-reader {
  padding: clamp(22px, 4vw, 34px);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.retrieval-reader-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 24px;
  padding-bottom: 20px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.retrieval-reader-head .eyebrow {
  margin-bottom: 8px;
}

.retrieval-reader-head h2 {
  max-width: 820px;
  margin-bottom: 8px;
  font-size: clamp(27px, 3.8vw, 40px);
}

.retrieval-kind {
  margin: 0;
  color: var(--muted);
  font-weight: 700;
}

.retrieval-source,
.retrieval-document-panel a {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 10px 16px;
  color: var(--white);
  font-weight: 800;
  background: var(--blue-800);
  border-radius: 8px;
}

.retrieval-content {
  display: grid;
  gap: 24px;
}

.retrieval-summary {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(280px, 0.85fr);
  gap: 22px;
  align-items: start;
}

.retrieval-description {
  margin: 0;
  color: #30445f;
  font-size: 18px;
  line-height: 1.85;
}

.retrieval-facts {
  display: grid;
  gap: 9px;
  padding: 18px 20px 18px 38px;
  margin: 0;
  color: var(--blue-950);
  background: #f2f7fd;
  border: 1px solid #d9e8f8;
  border-radius: 10px;
}

.retrieval-screenshot-feature {
  padding: clamp(14px, 2.4vw, 22px);
  overflow: hidden;
  background: #f5f8fb;
  border: 1px solid #d7e6f6;
  border-radius: 8px;
}

.retrieval-screenshot-visual {
  position: relative;
  min-height: clamp(360px, 45vw, 520px);
}

.retrieval-screenshot-main,
.retrieval-screenshot-detail {
  display: block;
  overflow: hidden;
  background: #f8fbff;
  border: 1px solid rgba(124, 152, 184, 0.32);
  box-shadow: 0 18px 42px rgba(8, 39, 92, 0.14);
}

.retrieval-screenshot-main {
  width: min(88%, 920px);
  border-radius: 8px;
}

.retrieval-screenshot-detail {
  position: absolute;
  right: 0;
  bottom: 0;
  width: min(58%, 620px);
  border-radius: 8px;
}

.retrieval-screenshot-main img,
.retrieval-screenshot-detail img {
  display: block;
  width: 100%;
  aspect-ratio: 2.25 / 1;
  object-fit: cover;
  object-position: top left;
  transition: transform 0.25s ease;
}

.retrieval-screenshot-detail img {
  aspect-ratio: 2.25 / 1;
}

.retrieval-screenshot-main:hover img,
.retrieval-screenshot-detail:hover img {
  transform: scale(1.025);
}

.retrieval-gallery {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.retrieval-table-section {
  min-width: 0;
}

.retrieval-table-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 14px;
}

.retrieval-table-heading h3 {
  margin: 0;
  color: var(--blue-950);
}

.retrieval-table-heading span {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

.retrieval-table-scroll {
  max-height: 680px;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
  scrollbar-color: #9dbcdc #edf4fb;
}

.retrieval-data-table {
  width: 100%;
  min-width: 1040px;
  border-collapse: separate;
  border-spacing: 0;
  color: #30445f;
  font-size: 14px;
  line-height: 1.55;
}

.retrieval-data-table th,
.retrieval-data-table td {
  padding: 13px 14px;
  text-align: left;
  vertical-align: top;
  border-right: 1px solid #e0eaf5;
  border-bottom: 1px solid #e0eaf5;
}

.retrieval-data-table th {
  position: sticky;
  top: 0;
  z-index: 1;
  color: var(--white);
  font-weight: 800;
  white-space: nowrap;
  background: var(--blue-800);
}

.retrieval-data-table th:last-child,
.retrieval-data-table td:last-child {
  border-right: 0;
}

.retrieval-data-table tbody tr:nth-child(even) {
  background: #f6f9fd;
}

.retrieval-data-table tbody tr:hover {
  background: #edf5fe;
}

.retrieval-data-table th:first-child,
.retrieval-data-table td:first-child,
.retrieval-data-table th:nth-last-child(-n + 2),
.retrieval-data-table td:nth-last-child(-n + 2) {
  text-align: center;
  white-space: nowrap;
}

.retrieval-data-table th:first-child,
.retrieval-data-table td:first-child {
  width: 64px;
}

.retrieval-data-table th:nth-child(2) {
  width: 34%;
}

.retrieval-data-table th:nth-child(3) {
  width: 23%;
}

.retrieval-data-table th:nth-child(4) {
  width: 22%;
}

.scholar-document {
  display: grid;
  gap: 24px;
  min-width: 0;
}

.scholar-document-intro {
  display: grid;
  gap: 12px;
  padding: clamp(18px, 3vw, 28px);
  background: #f6f9fd;
  border: 1px solid #dbe8f6;
  border-radius: 10px;
}

.scholar-document-intro p,
.scholar-document-footer p {
  margin: 0;
  color: #30445f;
  line-height: 1.7;
  overflow-wrap: anywhere;
  white-space: pre-line;
}

.scholar-document-intro p:first-of-type {
  color: var(--blue-950);
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 900;
}

.scholar-document-images {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.scholar-document-images img {
  width: auto;
  max-width: min(100%, 220px);
  max-height: 180px;
  object-fit: contain;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.scholar-metrics-table {
  width: min(100%, 560px);
  margin-top: 8px;
  border-collapse: separate;
  border-spacing: 0;
  overflow: hidden;
  color: #30445f;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.scholar-metrics-table th,
.scholar-metrics-table td {
  padding: 11px 14px;
  text-align: center;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.scholar-metrics-table th {
  color: var(--white);
  background: var(--blue-800);
}

.scholar-metrics-table th:last-child,
.scholar-metrics-table td:last-child {
  border-right: 0;
}

.scholar-metrics-table tbody tr:last-child td {
  border-bottom: 0;
}

.scholar-entries-scroll {
  max-height: 76vh;
  overflow: auto;
  border: 1px solid var(--line);
  border-radius: 10px;
  scrollbar-color: #9dbcdc #edf4fb;
}

.scholar-entries-table {
  width: 100%;
  min-width: 860px;
  border-collapse: separate;
  border-spacing: 0;
  color: #30445f;
  font-size: 14px;
}

.scholar-entries-table th,
.scholar-entries-table td {
  padding: 13px 14px;
  vertical-align: top;
  border-right: 1px solid #e0eaf5;
  border-bottom: 1px solid #e0eaf5;
}

.scholar-entries-table th {
  position: sticky;
  top: 0;
  z-index: 1;
  color: var(--white);
  text-align: left;
  white-space: nowrap;
  background: var(--blue-800);
}

.scholar-entries-table tbody tr:nth-child(even) {
  background: #f6f9fd;
}

.scholar-entries-table tbody tr:hover {
  background: #edf5fe;
}

.scholar-entries-table th:first-child,
.scholar-entries-table td:first-child,
.scholar-entries-table th:nth-last-child(-n + 2),
.scholar-entries-table td:nth-last-child(-n + 2) {
  text-align: center;
  white-space: nowrap;
}

.scholar-entries-table th:first-child,
.scholar-entries-table td:first-child {
  width: 64px;
}

.scholar-entries-table th:nth-child(2) {
  width: auto;
}

.scholar-entries-table td:nth-child(2) {
  min-width: 560px;
  line-height: 1.65;
  white-space: pre-line;
}

.scholar-document-footer {
  display: grid;
  gap: 8px;
  padding: 18px 20px;
  background: #f2f7fd;
  border-radius: 8px;
}

.retrieval-gallery a {
  display: block;
  overflow: hidden;
  background: #eef4fb;
  border: 1px solid var(--line);
  border-radius: 10px;
}

.retrieval-gallery img {
  display: block;
  width: 100%;
  height: 380px;
  object-fit: contain;
  transition: transform 0.25s ease;
}

.retrieval-gallery a:hover img {
  transform: scale(1.02);
}

.retrieval-document-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 24px;
  background: #f2f7fd;
  border: 1px solid #d9e8f8;
  border-radius: 10px;
}

.retrieval-document-panel p,
.retrieval-directory {
  margin: 0;
}

.retrieval-directory {
  margin-top: 22px;
  color: var(--muted);
  text-align: center;
}

.retrieval-directory .text-link {
  margin-top: 0;
}

.review-content h3 {
  margin: 26px 0 10px;
  padding-left: 12px;
  border-left: 4px solid var(--blue-700);
}

.review-content h3:first-child {
  margin-top: 0;
}

.review-content p {
  margin-bottom: 14px;
  color: #263b56;
  font-size: 16px;
  line-height: 1.85;
  text-align: justify;
  text-indent: 0;
  overflow-wrap: anywhere;
}

.review-content .review-inline-link {
  display: inline-block;
  margin-left: 6px;
  color: var(--blue-800);
  font-weight: 800;
  text-align: left;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.review-content .expert-person,
.review-content .leader-heading {
  margin: 26px 0 12px;
  padding-left: 12px;
  color: var(--blue-900);
  font-size: 20px;
  font-weight: 900;
  line-height: 1.55;
  border-left: 4px solid var(--blue-700);
  text-align: left;
  text-indent: 0;
}

.review-content .expert-person strong {
  font-size: inherit;
  font-weight: inherit;
}

.review-content .leader-subheading,
.review-content .expert-subheading {
  margin: 20px 0 9px;
  padding-left: 0;
  color: #0f2238;
  font-size: 20px;
  font-weight: 900;
  line-height: 1.55;
  border-left: 0;
  text-align: left;
}


.review-content .review-section-heading {
  margin: 28px 0 14px;
  color: var(--blue-950);
  font-size: 24px;
  font-weight: 900;
  text-align: left;
}

.review-content .expert-signature {
  margin: 4px 0 10px;
  color: #425670;
  text-align: right;
  text-indent: 0;
}

.review-content .expert-signature span {
  display: block;
}

.review-image {
  max-width: 620px;
  margin: 16px auto 26px;
  padding: 12px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.review-image img {
  display: block;
  width: 100%;
  height: auto;
}

.review-image figcaption {
  margin-top: 8px;
  color: var(--muted);
  font-size: 14px;
  text-align: center;
}

.review-image-fallback {
  text-align: center;
}

.review-image-fallback a {
  color: var(--blue-800);
  font-weight: 800;
}

.site-footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 16px;
  padding: 28px clamp(20px, 5vw, 76px);
  color: rgba(255, 255, 255, 0.84);
  background: var(--blue-950);
}

.site-footer a {
  color: var(--white);
  font-weight: 800;
}

.site-footer p {
  margin: 0;
}

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 1050px) {
  .site-header {
    align-items: flex-start;
    flex-wrap: wrap;
  }

  .nav-toggle {
    display: inline-flex;
    margin-left: auto;
    padding: 8px 12px;
    color: var(--white);
    background: var(--blue-800);
    border: 0;
    border-radius: 8px;
  }

  .main-nav {
    display: none;
    flex-basis: 100%;
    justify-content: flex-start;
    padding-bottom: 8px;
  }

  .main-nav.open {
    display: flex;
  }

  .hero,
  .content-layout,
  .evidence-layout,
  .book-overview,
  .book-reader-shell,
  .page-shell {
    grid-template-columns: 1fr;
  }

  .teacher-sidebar {
    position: static;
  }

  .book-tabs {
    position: static;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    max-height: none;
    padding-right: 0;
  }

  .stats-grid,
  .resource-grid,
  .link-grid,
  .timeline,
  .quote-grid,
  .module-grid,
  .retrieval-modules {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .video-grid-featured .video-card:first-child {
    grid-template-columns: 1fr;
  }

  .review-reader-head {
    display: block;
  }

  .retrieval-reader-head,
  .retrieval-document-panel {
    align-items: flex-start;
    flex-direction: column;
  }

  .retrieval-screenshot-feature {
    grid-template-columns: 1fr;
  }

  .retrieval-screenshot-visual {
    min-height: 360px;
  }
}

@media (max-width: 680px) {
  .brand {
    min-width: 0;
  }

  .brand strong {
    font-size: 15px;
  }

  .section {
    padding: 56px 18px;
  }

  .hero {
    min-height: auto;
    padding-top: 72px;
  }

  .hero-content,
  .hero-panel {
    padding-bottom: 0;
    margin-bottom: 0;
  }

  h1 {
    font-size: 40px;
  }

  .stats-grid,
  .resource-grid,
  .link-grid,
  .timeline,
  .quote-grid,
  .paper-board,
  .module-grid,
  .retrieval-modules,
  .retrieval-summary,
  .retrieval-gallery {
    grid-template-columns: 1fr;
  }

  .video-grid-featured .video-card:first-child .video-thumb {
    min-height: 0;
  }

  .columns {
    columns: 1;
  }

  .review-tab {
    flex: 1 1 calc(50% - 8px);
  }

  .review-content,
  .paper-content {
    max-height: none;
    overflow: visible;
  }

  .pdf-reader iframe {
    height: 76vh;
    min-height: 480px;
  }

  .review-reader-students .pdf-reader iframe {
    height: 82vh;
    min-height: 560px;
  }

  .retrieval-module {
    min-height: 152px;
  }

  .retrieval-gallery img {
    height: auto;
    max-height: 72vh;
  }

  .retrieval-screenshot-feature {
    padding: 14px;
  }

  .retrieval-screenshot-visual {
    display: grid;
    gap: 12px;
    min-height: 0;
  }

  .retrieval-screenshot-main,
  .retrieval-screenshot-detail {
    position: static;
    width: 100%;
  }

  .retrieval-screenshot-main img,
  .retrieval-screenshot-detail img {
    aspect-ratio: 1.72 / 1;
  }

  .retrieval-table-heading {
    align-items: flex-start;
    flex-direction: column;
    gap: 4px;
  }

  .retrieval-table-scroll {
    max-height: 72vh;
  }

  .scholar-entries-scroll {
    max-height: 72vh;
  }

  .scholar-document-images img {
    max-width: 100%;
  }

  .book-tabs,
  .book-contents-list,
  .book-chapter-items,
  .book-section-items,
  .book-subsection-items,
  .courseware-catalog,
  .courseware-file-list {
    grid-template-columns: 1fr;
  }

  .courseware-directory-head {
    align-items: flex-start;
    flex-direction: column;
    gap: 8px;
  }

  .courseware-catalog li {
    grid-template-columns: 48px minmax(0, 1fr);
    gap: 12px;
    padding: 16px;
  }

  .courseware-cover {
    grid-column: 2;
    justify-self: start;
    width: min(100%, 132px);
  }

  .courseware-number {
    width: 44px;
    height: 44px;
    font-size: 15px;
  }

  .book-detail,
  .book-catalog {
    max-height: none;
    overflow: visible;
  }

  .paper-list li {
    grid-template-columns: 46px minmax(0, 1fr);
    padding: 14px;
  }
}

/* 2026 editorial refresh: restrained academic presentation */
:root {
  --blue-950: #17263a;
  --blue-900: #203b59;
  --blue-800: #2b5378;
  --blue-700: #396b91;
  --blue-600: #527f9f;
  --blue-100: #edf2f5;
  --blue-050: #f7f8f8;
  --ink: #20252a;
  --muted: #6e7479;
  --line: #dfe2e3;
  --gold: #9a7137;
  --shadow: 0 8px 24px rgba(24, 36, 48, 0.06);
  --radius: 2px;
}

body {
  font-family: "Microsoft YaHei UI", "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", Arial, sans-serif;
  background: #fff;
}

button,
.main-nav,
.button,
.eyebrow,
.brand small,
.courseware-category,
.site-footer {
  font-family: inherit;
}

.site-header {
  min-height: 82px;
  gap: 34px;
  padding: 12px max(24px, calc((100vw - 1320px) / 2));
  background: rgba(255, 255, 255, 0.97);
  border-bottom-color: #e7e7e5;
  backdrop-filter: blur(8px);
}

.brand {
  min-width: 300px;
}

.brand-mark {
  width: 40px;
  height: 40px;
  color: #fff;
  font-family: "STKaiti", "KaiTi", "Microsoft YaHei", sans-serif;
  font-weight: 500;
  background: #1f3448;
  border-radius: 0;
  box-shadow: none;
}

.brand strong {
  color: #202a33;
  font-size: 23px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.brand small {
  color: #868a8d;
  font-size: 11px;
  letter-spacing: 0.2em;
}

.main-nav {
  gap: 0;
}

.main-nav a {
  position: relative;
  padding: 12px 12px;
  color: #4c5359;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.35;
  border-radius: 0;
}

.main-nav a::after {
  position: absolute;
  right: 10px;
  bottom: 5px;
  left: 10px;
  height: 1px;
  content: "";
  background: #223e58;
  transform: scaleX(0);
  transition: transform 0.2s ease;
}

.main-nav a:hover,
.main-nav a.active {
  color: #182b3d;
  background: transparent;
}

.main-nav a:hover::after,
.main-nav a.active::after {
  transform: scaleX(1);
}

.section {
  padding-top: clamp(68px, 8vw, 104px);
  padding-bottom: clamp(68px, 8vw, 104px);
}

.page-shell {
  max-width: 1160px;
}

.hero {
  border-bottom-color: #e7e7e5;
}

.home-hero {
  grid-template-columns: minmax(0, 1.18fr) minmax(300px, 0.82fr);
  min-height: min(760px, calc(100vh - 82px));
  padding: clamp(70px, 9vw, 120px) max(24px, calc((100vw - 1160px) / 2));
  place-items: center stretch;
  background: #f7f6f2;
}

.home-hero .hero-bg {
  inset: 0;
  background:
    linear-gradient(90deg, rgba(255, 255, 255, 0.78), rgba(247, 246, 242, 0.25)),
    repeating-linear-gradient(90deg, transparent 0, transparent 79px, rgba(35, 55, 72, 0.035) 80px);
  filter: none;
  transform: none;
}

.home-hero .hero-content {
  max-width: 720px;
  margin: 0;
  padding: 26px 0;
  text-align: left;
}

.home-hero .hero-content h1,
.home-hero .hero-lead {
  margin-left: 0;
}

.home-hero .hero-content h1 {
  margin-bottom: 28px;
  color: #182735;
  font-size: clamp(48px, 6.5vw, 78px);
  font-weight: 500;
  line-height: 1.15;
  letter-spacing: 0.035em;
}

.home-hero .hero-lead {
  max-width: 650px;
  color: #5e6569;
  font-size: 17px;
  line-height: 2;
}

.home-hero .hero-actions {
  justify-content: flex-start;
  margin-top: 34px;
}

.eyebrow {
  color: var(--gold);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.14em;
}

.button {
  min-height: 44px;
  padding: 9px 22px;
  border-radius: 0;
  transition: color 0.2s ease, background 0.2s ease;
}

.button.primary {
  background: #213d56;
  border-color: #213d56;
}

.button.secondary {
  color: #213d56;
  background: transparent;
  border-color: #9aa5ad;
}

.button.primary:hover {
  background: #162c40;
}

.button.secondary:hover {
  background: #fff;
}

.home-hero-books {
  position: relative;
  z-index: 1;
  min-height: 470px;
}

.hero-book {
  position: absolute;
  margin: 0;
  background: #fff;
  border: 8px solid #fff;
  box-shadow: 0 22px 50px rgba(23, 34, 43, 0.16);
}

.hero-book img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-book-main {
  top: 8px;
  left: 8%;
  width: min(64%, 260px);
  aspect-ratio: 0.72;
  transform: rotate(-2.5deg);
}

.hero-book-side {
  right: 2%;
  bottom: 54px;
  width: min(52%, 210px);
  aspect-ratio: 0.72;
  transform: rotate(4deg);
}

.home-hero-books > p {
  position: absolute;
  right: 0;
  bottom: 0;
  left: 3%;
  margin: 0;
  padding: 17px 20px;
  background: rgba(255, 255, 255, 0.94);
  border-left: 3px solid #9a7137;
}

.home-hero-books strong,
.home-hero-books span {
  display: block;
}

.home-hero-books strong {
  color: #23384a;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.home-hero-books span {
  margin-top: 4px;
  color: #777c80;
  font-size: 13px;
}

.home-professor-card {
  position: relative;
  z-index: 1;
  display: grid;
  align-content: end;
  min-height: 520px;
}

.home-professor-portrait {
  position: relative;
  width: min(100%, 360px);
  margin: 0 0 0 auto;
  background: #fff;
  border: 8px solid #fff;
  outline: 1px solid rgba(154, 113, 55, 0.22);
  box-shadow: 0 18px 42px rgba(23, 34, 43, 0.14);
}

.home-professor-portrait::before {
  content: none;
}

.home-professor-portrait img {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 0.72;
  object-fit: cover;
  object-position: center top;
}

.home-professor-summary {
  width: min(100%, 390px);
  margin: 10px 0 0 auto;
  padding: 22px 24px;
  background: rgba(255, 255, 255, 0.96);
  border-left: 3px solid #9a7137;
  box-shadow: 0 12px 30px rgba(23, 34, 43, 0.1);
}

.home-professor-summary h2 {
  margin: 0 0 12px;
  color: #23384a;
  font-size: 38px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.home-professor-summary .eyebrow {
  font-size: 17px;
}

.home-professor-summary p:last-child {
  margin: 0;
  color: #5f666b;
  font-size: 16px;
  line-height: 2;
}

.professor-profile {
  padding-top: clamp(58px, 7vw, 86px);
  padding-bottom: clamp(58px, 7vw, 86px);
}

.professor-profile-grid {
  width: min(100%, 960px);
  padding: clamp(34px, 5vw, 58px) 0;
  margin: 0 auto;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.professor-profile-text {
  max-width: 760px;
}

.professor-profile-text h2 {
  max-width: 680px;
  margin-bottom: 24px;
  font-size: clamp(34px, 4.2vw, 48px);
  line-height: 1.2;
}

.professor-profile-text p:not(.eyebrow) {
  max-width: 760px;
  color: #4f5b63;
  font-size: 17px;
  line-height: 2;
  text-align: justify;
}

h1,
h2,
h3 {
  font-family: "Microsoft YaHei UI", "Microsoft YaHei", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  font-weight: 500;
}

h2,
h3,
.page-title {
  color: #24394b;
}

.page-title {
  font-size: clamp(34px, 4.5vw, 52px);
  letter-spacing: 0.025em;
  line-height: 1.18;
  text-wrap: balance;
}

.phrase-title {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  column-gap: 0.08em;
}

.phrase-title span {
  display: inline-block;
  white-space: nowrap;
}

.module-intro {
  max-width: 820px;
  margin-bottom: 56px;
}

.module-intro > .eyebrow {
  color: var(--gold);
  font-size: clamp(18px, 1.8vw, 24px);
  font-weight: 800;
  line-height: 1.35;
}

.module-intro p,
.section-head p {
  line-height: 1.9;
}

#overview .section-head {
  max-width: 720px;
}

.module-grid {
  gap: 0;
  margin-top: 48px;
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}

.module-grid a {
  position: relative;
  min-height: 174px;
  padding: 28px 26px 46px;
  border: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  box-shadow: none;
}

.module-grid a::after {
  position: absolute;
  right: 24px;
  bottom: 19px;
  color: #9a7137;
  content: "→";
  font-family: Arial, sans-serif;
  font-size: 18px;
  transition: transform 0.2s ease;
}

.module-grid a:hover {
  z-index: 1;
  background: #f8f7f3;
  border-color: var(--line);
  transform: none;
}

.module-grid a:hover::after {
  transform: translateX(4px);
}

.module-grid strong {
  color: #24394b;
  font-size: 19px;
  font-weight: 600;
}

.module-grid span {
  font-size: 14px;
  line-height: 1.8;
}

.stats-grid div,
.resource-grid article,
.link-grid a,
.feature-card,
.detail-stack article,
.timeline article,
.quote-grid blockquote,
.courseware-directory,
.paper-reader,
.book-reader,
.evidence-layout,
.review-reader,
.retrieval-reader {
  border-color: #e0e3e4;
  border-radius: 2px;
  box-shadow: var(--shadow);
}

.paper-board div,
.paper-tab,
.retrieval-module {
  color: #24394b;
  background: #f5f6f5;
  border: 1px solid #dce0e1;
  border-radius: 2px;
  box-shadow: none;
}

.paper-board strong,
.paper-board span,
.retrieval-module strong,
.retrieval-module small {
  color: inherit;
}

.paper-tab:hover,
.paper-tab.active,
.retrieval-module:hover,
.retrieval-module.active {
  background: #213d56;
  color: #fff;
  box-shadow: none;
  filter: none;
  transform: none;
}

.retrieval-module::after {
  display: none;
}

.retrieval-module span {
  color: #9a7137;
}

.paper-tab.active span,
.paper-tab.active strong,
.retrieval-module.active span {
  color: #fff;
}

.book-tab,
.review-tab,
.attachment-bar a {
  border-radius: 0;
  box-shadow: none;
}

.book-tab:hover,
.review-tab:hover {
  transform: none;
}

.paper-list li,
.book-catalog li,
.book-contents-list li,
.courseware-catalog li,
.scholar-document-intro,
.retrieval-facts,
.retrieval-document-panel {
  background: #f7f8f8;
  border-color: #e1e4e5;
  border-radius: 2px;
}

.book-contents-list .book-chapter-item {
  background: transparent;
  border: 0;
  border-radius: 0;
}

.book-contents-list .book-chapter-items {
  background: transparent;
  border: 0;
  border-radius: 0;
}

.book-contents-list .book-section-item,
.book-contents-list .book-section-items {
  background: transparent;
  border: 0;
  border-radius: 0;
}

.book-contents-list .book-subsection-item,
.book-contents-list .book-subsection-items {
  background: transparent;
  border: 0;
  border-radius: 0;
}

.site-footer {
  padding: 34px max(24px, calc((100vw - 1160px) / 2));
  color: #c9ced2;
  background: #1e2d39;
}

.site-footer code {
  color: #fff;
}

@media (max-width: 1050px) {
  .site-header {
    padding-right: 24px;
    padding-left: 24px;
  }

  .nav-toggle {
    color: #213d56;
    background: transparent;
    border: 1px solid #9aa5ad;
    border-radius: 0;
  }

  .main-nav {
    padding-top: 8px;
    border-top: 1px solid var(--line);
  }

  .home-hero {
    grid-template-columns: minmax(0, 1fr) minmax(270px, 0.7fr);
  }

  .home-professor-card {
    min-height: 480px;
  }

  .home-professor-portrait {
    width: min(100%, 330px);
  }

}

@media (max-width: 760px) {
  .home-hero {
    grid-template-columns: 1fr;
    padding-top: 58px;
  }

  .home-hero .hero-content h1 {
    font-size: clamp(42px, 13vw, 58px);
  }

  .home-hero-books {
    width: min(100%, 430px);
    min-height: 400px;
    margin: 4px auto 0;
  }

  .home-professor-card {
    width: min(100%, 430px);
    min-height: auto;
    margin: 18px auto 0;
  }

  .home-professor-portrait,
  .home-professor-summary {
    margin-right: auto;
    margin-left: auto;
  }

  .home-professor-summary {
    margin-top: 10px;
  }
}

@media (max-width: 680px) {
  .site-header {
    min-height: 70px;
    padding: 10px 18px;
  }

  .brand strong {
    font-size: 18px;
  }

  .brand small {
    display: none;
  }

  .brand-mark {
    width: 36px;
    height: 36px;
  }

  .module-grid {
    grid-template-columns: 1fr;
  }

  .module-grid a {
    min-height: 132px;
  }

  .home-professor-summary {
    padding: 18px;
  }

  .professor-profile-grid {
    padding: 30px 0;
  }

  .professor-profile-text h2 {
    font-size: 32px;
  }

  .professor-profile-text p:not(.eyebrow) {
    font-size: 16px;
    line-height: 1.9;
    text-align: left;
  }

  .page-title {
    font-size: 34px;
  }

  .phrase-title {
    display: block;
  }

  .phrase-title span {
    white-space: normal;
  }
}

/* Courseware PDF refresh */
.courseware-catalog {
  grid-template-columns: 1fr;
  gap: 18px;
}

.courseware-catalog li.courseware-item {
  grid-template-columns: 58px minmax(0, 1fr) minmax(118px, 150px);
  width: 100%;
  background: #f7f8f8;
}

.courseware-item-body {
  min-width: 0;
}

.courseware-toggle {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  min-height: 44px;
  padding: 9px 16px;
  margin-top: 16px;
  color: #fff;
  font: inherit;
  font-weight: 800;
  background: #2b5378;
  border: 1px solid #2b5378;
  border-radius: 2px;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease;
}

.courseware-toggle:hover,
.courseware-toggle[aria-expanded="true"] {
  background: #1f3d59;
  border-color: #1f3d59;
}

.courseware-toggle span {
  font-size: 18px;
  line-height: 1;
}

.courseware-panel {
  grid-column: 1 / -1;
  margin-top: 20px;
}

.courseware-panel[hidden] {
  display: none;
}

.courseware-chapter-scroll {
  display: grid;
  max-height: min(82vh, 760px);
  gap: 16px;
  padding: 16px;
  overflow: auto;
  background: #fff;
  border: 1px solid #dfe2e3;
  scrollbar-color: #9aa5ad #eef1f2;
}

.courseware-chapter {
  display: grid;
  gap: 0;
  min-width: 0;
  background: #f8f9f9;
  border: 1px solid #e1e4e5;
}

.courseware-chapter-head {
  display: block;
}

.courseware-chapter h4 {
  min-width: 0;
  margin: 0;
  color: #24394b;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.55;
  overflow-wrap: anywhere;
}

.courseware-chapter-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  width: 100%;
  min-height: 54px;
  padding: 13px 14px;
  color: inherit;
  font: inherit;
  font-weight: inherit;
  line-height: inherit;
  text-align: left;
  background: transparent;
  border: 0;
  cursor: pointer;
}

.courseware-chapter-toggle:hover,
.courseware-chapter-toggle[aria-expanded="true"] {
  background: #eef2f3;
}

.courseware-chapter-toggle span:first-child {
  min-width: 0;
  overflow-wrap: anywhere;
}

.courseware-chapter-icon {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  width: 26px;
  height: 26px;
  color: #fff;
  font-size: 17px;
  line-height: 1;
  background: #2b5378;
}

.courseware-pdf {
  min-height: 420px;
  margin: 0 14px 14px;
  background: #eef1f2;
  border: 1px solid #d8dde0;
}

.courseware-pdf[hidden] {
  display: none;
}

.courseware-pdf iframe {
  display: block;
  width: 100%;
  height: clamp(420px, 58vh, 680px);
  border: 0;
}

.courseware-pdf .pdf-fallback {
  margin: 0;
  padding: 10px 12px;
  color: #6e7479;
  font-size: 13px;
}

@media (max-width: 680px) {
  .courseware-catalog li.courseware-item {
    grid-template-columns: 48px minmax(0, 1fr);
  }

  .courseware-panel {
    grid-column: 1 / -1;
  }

  .courseware-chapter-scroll {
    max-height: none;
    padding: 10px;
    overflow: visible;
  }

  .courseware-chapter {
    padding: 0;
  }

  .courseware-chapter-toggle {
    padding: 12px;
  }

  .courseware-pdf {
    min-height: 360px;
    margin: 0 10px 10px;
  }

  .courseware-pdf iframe {
    height: 70vh;
    min-height: 360px;
  }
}

@media print {
  body {
    min-width: 0;
  }
}