:root {
  color-scheme: light;
  --paper: #f8f7f2;
  --white: #fffefa;
  --ink: #172f2a;
  --muted: #4e635b;
  --green: #214c42;
  --line: #dbe0d5;
  --serif: "Songti SC", "Noto Serif CJK SC", SimSun, serif;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--ink);
  background: var(--paper);
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; }
a { color: inherit; text-decoration: none; }
a:focus-visible, button:focus-visible, input:focus-visible { outline: 3px solid #b2813b; outline-offset: 4px; }
[hidden] { display: none !important; }
.wrap { width: min(1080px, 100% - 64px); margin-inline: auto; }
.top { border-bottom: 1px solid var(--line); background: var(--white); }
.top .wrap { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 14px; }
.brand { display: inline-flex; align-items: center; gap: 11px; font-family: Georgia, serif; font-size: 17px; }
.brand img { display: block; width: 34px; height: 34px; }
.top-label { color: var(--muted); font-size: 13px; }
main.wrap { padding-block: 38px 60px; }
h1, h2, h3, p { margin: 0; }
h1, h2, h3 { font-family: var(--serif); }
.eyebrow { color: #d2e2d2; font: 600 11px/1.4 -apple-system, BlinkMacSystemFont, sans-serif; letter-spacing: .2em; }
.hero {
  position: relative; isolation: isolate; overflow: hidden; padding: clamp(30px, 6vw, 76px);
  min-height: 300px; display: grid; align-content: center; border-radius: 15px;
  background: #173d38; color: #fffdf5;
}
.hero h1 { font-size: clamp(35px, 5.2vw, 65px); letter-spacing: -.035em; line-height: 1.18; margin: 14px 0; }
.hero p:last-of-type { color: #d9e8dc; line-height: 1.8; font-size: 15px; }
.hero-score { z-index: -1; position: absolute; right: -20px; top: 50%; width: min(51%, 520px); transform: translateY(-50%); color: #dec093; opacity: .48; }
.section-head { display: flex; justify-content: space-between; align-items: baseline; gap: 12px; margin: 36px 0 15px; }
.section-head h2 { font-size: 28px; }
.section-head span { color: var(--muted); font-size: 13px; }
.course-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; }
.card { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 15px; padding: 21px; border: 1px solid var(--line); border-radius: 12px; background: var(--white); }
.card:hover, .material-open:hover { border-color: #86a69a; background: #f1f5ed; }
.card h3 { font-size: 21px; line-height: 1.35; }
.card p { margin-top: 6px; color: var(--muted); font-size: 13px; }
.index { display: grid; place-items: center; border-radius: 8px; width: 52px; height: 52px; font: 24px/1 Georgia, serif; background: #e8eee3; color: var(--green); }
.arrow { color: var(--green); font-size: 22px; }
.crumb { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px; color: var(--muted); font-size: 13px; margin-bottom: 20px; }
.crumb a { text-decoration: underline; text-underline-offset: 3px; }
.course-intro { padding: 32px; border-radius: 14px; background: #173d38; color: #fffdf5; }
.course-intro h1 { font-size: clamp(29px, 5vw, 51px); margin-top: 9px; }
.lesson-list { display: grid; gap: 10px; }
.lesson-list .card { grid-template-columns: minmax(78px, auto) 1fr auto; }
.lesson-badge { color: var(--green); font-size: 14px; }
.empty { background: var(--white); border: 1px solid var(--line); padding: 25px; border-radius: 12px; color: var(--muted); }
.material-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 340px), 1fr)); gap: 16px; margin-top: 24px; }
.material-open { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 14px; min-height: 82px; padding: 18px 24px; border: 1px solid var(--line); border-radius: 12px; background: var(--white); font-size: 19px; font-weight: 600; }
.material-open svg { width: 25px; height: 25px; color: var(--green); }
.books { padding: 20px 24px; border: 1px solid var(--line); border-radius: 12px; background: var(--white); }
.books h3 { color: var(--green); font-size: 17px; }
.books h3:not(:first-child) { margin-top: 18px; }
.book-list { display: grid; gap: 12px; list-style: none; padding: 0; margin: 10px 0 0; }
.book-list p { margin-top: 4px; color: var(--muted); font-size: 14px; line-height: 1.5; }
.reader-heading { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 0 16px; margin-bottom: 10px; }
.reader-heading a { padding: 9px 11px; border: 1px solid var(--line); border-radius: 7px; color: var(--green); background: var(--white); font-size: 13px; }
.reader-kind { color: var(--muted); font-size: 13px; margin-bottom: 3px; }
.handout-reader .zoom .sheet { width: max(600px, calc(115vh * var(--ratio))); }
footer { border-top: 1px solid var(--line); color: var(--muted); padding: 21px 0; font-size: 12px; }
.reader-wrap { width: min(1360px, 100% - 48px); margin-inline: auto; padding: 22px 0 28px; }
.reader-wrap .crumb { margin-bottom: 10px; }
.reader-wrap h1 { font-size: clamp(22px, 3vw, 34px); margin-bottom: 13px; }
.reader { padding: 10px; background: #203833; border-radius: 13px; color: #f7f8f1; }
.frame { background: #12241f; border-radius: 7px; min-height: 130px; max-height: 70vh; overflow: auto; touch-action: pan-y pinch-zoom; overscroll-behavior-inline: contain; }
.frame.zoom { touch-action: auto; }
.sheet { position: relative; margin-inline: auto; width: min(100%, calc(67vh * var(--ratio))); aspect-ratio: var(--ratio); }
.zoom .sheet { width: max(100%, calc(115vh * var(--ratio))); }
.sheet img, .sheet video { display: block; width: 100%; height: 100%; object-fit: contain; }
.sheet img { -webkit-user-drag: none; }
.toolbar { display: flex; justify-content: center; flex-wrap: wrap; align-items: center; gap: 8px; padding: 10px 2px 0; }
button, .page-input { font: inherit; }
.toolbar button, .page-input {
  min-height: 40px; color: inherit; background: #28463e; border: 1px solid #5b746a; border-radius: 7px;
}
.toolbar button { cursor: pointer; padding-inline: 12px; font-size: 13px; }
.toolbar button:disabled { opacity: .48; cursor: default; }
.toolbar button:not(:disabled):hover { background: #426057; }
.jump { display: flex; align-items: center; gap: 6px; font-size: 13px; white-space: nowrap; }
.page-input { width: 48px; text-align: center; appearance: textfield; }
.page-input::-webkit-inner-spin-button { appearance: none; }
.audio { display: grid; grid-template-columns: repeat(auto-fit, minmax(min(100%, 245px), 1fr)); gap: 9px; margin-top: 10px; }
.audio label { display: grid; gap: 5px; background: var(--white); color: var(--ink); padding: 9px 12px; border-radius: 7px; font-size: 13px; }
audio { width: 100%; }
.reader:fullscreen, .reader.expanded { overflow: auto; border-radius: 0; }
.reader.expanded { position: fixed; inset: 0; z-index: 3; }
body:has(.reader.expanded) { overflow: hidden; }
.reader:fullscreen .frame, .reader.expanded .frame { max-height: 84vh; }
.reader:fullscreen .sheet, .reader.expanded .sheet { width: min(100%, calc(83vh * var(--ratio))); }
.reader:fullscreen .zoom .sheet, .reader.expanded .zoom .sheet { width: max(100%, calc(115vh * var(--ratio))); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.error { padding: 12px; background: var(--white); color: #632e22; border-radius: 7px; }
@media (max-width: 700px) {
  .wrap, .reader-wrap { width: calc(100% - 30px); }
  .top .wrap { min-height: 58px; }
  .top-label { display: none; }
  main.wrap { padding-block: 20px 36px; }
  .hero { min-height: 250px; }
  .hero-score { width: 65%; right: -48px; opacity: .28; }
  .course-grid, .material-grid { grid-template-columns: 1fr; gap: 10px; }
  .material-open { min-height: 70px; padding: 15px; }
  .books { padding: 16px; }
  .section-head { margin-top: 27px; }
  .section-head h2 { font-size: 23px; }
  .course-intro { padding: 24px 18px; }
  .card { padding: 15px; }
  .card h3 { font-size: 18px; }
  .reader { padding: 6px; }
  .toolbar { gap: 5px; }
  .toolbar button { min-height: 44px; padding-inline: 8px; }
  .page-input { min-height: 44px; font-size: 16px; }
}