:root {
  --paper: #f4f2ed;
  --surface: #fffefa;
  --ink: #18263b;
  --muted: #536273;
  --muted-light: #aeb7c4;
  --line: #c8ced4;
  --navy: #16263f;
  --navy-soft: #213754;
  --blue: #1e4f91;
  --accent: #c45b43;
  --accent-soft: #f1ded7;
  --serif: "Noto Serif SC", "Songti SC", Georgia, serif;
  --sans: "Noto Sans SC", "Microsoft YaHei", sans-serif;
  --mono: "DM Mono", "SFMono-Regular", Consolas, monospace;
  --wrap: 1180px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.7;
}
a { color: inherit; text-decoration: none; }
button, input { font: inherit; }
.wrap { width: min(var(--wrap), calc(100% - 64px)); margin-inline: auto; }

/* Header */
.site-header { background: var(--surface); }
.topline {
  background: var(--navy);
  color: #d9e1eb;
  font: 12px var(--mono);
  letter-spacing: .035em;
}
.topline-inner {
  min-height: 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.header-main {
  min-height: 91px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 36px;
  border-bottom: 1px solid var(--line);
}
.brand { display: inline-flex; flex-direction: column; gap: 1px; min-width: 205px; }
.brand-kicker, .section-kicker, .aside-kicker, .notice-label {
  color: var(--blue);
  font: 500 11px var(--mono);
  letter-spacing: .11em;
  text-transform: uppercase;
}
.brand-kicker { color: var(--muted); letter-spacing: .13em; }
.brand-title { font: 700 23px var(--serif); letter-spacing: -.04em; }
.brand-title b { color: var(--accent); font-weight: 700; }
.main-nav { display: flex; align-items: center; gap: 32px; margin-left: auto; }
.main-nav a {
  position: relative;
  padding: 35px 0 31px;
  color: var(--muted);
  font-size: 14px;
}
.main-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform .2s ease;
}
.main-nav a:hover, .main-nav a:focus-visible { color: var(--ink); }
.main-nav a:hover::after, .main-nav a:focus-visible::after { transform: scaleX(1); }
.header-action {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  border: 1px solid var(--ink);
  padding: 9px 13px;
  color: var(--ink);
  font-size: 13px;
  white-space: nowrap;
}
.header-action span { color: var(--accent); font-size: 16px; line-height: 1; }

/* Hero */
.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(360px, .9fr);
  gap: 92px;
  align-items: center;
  padding-top: 86px;
  padding-bottom: 82px;
}
.hero-copy { max-width: 690px; }
.hero h1 {
  margin: 18px 0 25px;
  font: 800 clamp(47px, 6vw, 79px)/1.06 var(--serif);
  letter-spacing: -.085em;
}
.hero h1 em { color: var(--accent); font-style: normal; }
.hero-lead { max-width: 640px; margin: 0; color: var(--muted); font-size: 17px; line-height: 2; }
.hero-meta {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 42px;
  border-top: 1px solid var(--line);
}
.hero-meta div { padding: 17px 18px 0 0; border-right: 1px solid var(--line); }
.hero-meta div + div { padding-left: 18px; }
.hero-meta div:last-child { border-right: 0; }
.hero-meta span { display: block; margin-bottom: 7px; color: var(--muted); font: 11px var(--mono); }
.hero-meta strong { display: block; font-size: 13px; line-height: 1.6; font-weight: 600; }

.overview-panel { border: 1px solid var(--ink); background: var(--surface); }
.panel-heading {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 15px 19px;
  background: var(--navy);
  color: #e7edf4;
  font: 10px var(--mono);
  letter-spacing: .07em;
}
.overview-row {
  display: grid;
  grid-template-columns: 83px 1fr;
  gap: 16px;
  padding: 23px 19px;
  border-bottom: 1px solid var(--line);
}
.overview-row.is-current { border-left: 4px solid var(--accent); padding-left: 15px; background: #fbf7f2; }
.overview-week { color: var(--accent); font: 500 12px var(--mono); }
.overview-row strong { display: block; font-size: 15px; font-weight: 700; }
.overview-row small { display: block; margin-top: 4px; color: var(--muted); font-size: 12px; }
.panel-foot { padding: 15px 19px 17px; color: var(--muted); font-size: 12px; }

/* Note and common sections */
.notice {
  display: grid;
  grid-template-columns: 140px minmax(0, 1fr) auto;
  gap: 24px;
  align-items: center;
  padding: 19px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.notice-label { color: var(--accent); }
.notice p { margin: 0; color: var(--muted); font-size: 13px; }
.notice a, .text-link { color: var(--blue); font-size: 13px; font-weight: 700; white-space: nowrap; }
.notice a span, .text-link span { margin-left: 7px; color: var(--accent); font-size: 17px; vertical-align: -1px; }
.section { padding-top: 112px; padding-bottom: 116px; }
.section-heading {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 50px;
  margin-bottom: 43px;
}
.section-heading h2 {
  margin: 13px 0 0;
  font: 700 clamp(31px, 4vw, 49px)/1.15 var(--serif);
  letter-spacing: -.07em;
}
.section-intro { max-width: 430px; margin: 0; color: var(--muted); font-size: 14px; line-height: 1.9; }

/* Tutorial catalogue */
.toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  margin-bottom: 30px;
}
.search-box {
  display: flex;
  align-items: center;
  width: min(330px, 100%);
  height: 42px;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--muted);
}
.search-box span { padding: 0 11px 0 14px; font-size: 20px; line-height: 1; }
.search-box input { width: 100%; height: 100%; border: 0; outline: 0; background: transparent; color: var(--ink); font-size: 14px; }
.search-box:focus-within { border-color: var(--blue); box-shadow: 0 0 0 2px #1e4f9118; }
.filters { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 0; }
.filter {
  border: 1px solid var(--line);
  border-right: 0;
  padding: 9px 13px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
}
.filter:last-child { border-right: 1px solid var(--line); }
.filter:hover, .filter:focus-visible { color: var(--ink); background: #ece9e3; }
.filter.active { border-color: var(--navy); background: var(--navy); color: #fff; }
.filter.active + .filter { border-left-color: var(--navy); }
.catalog-layout { display: grid; grid-template-columns: 228px minmax(0, 1fr); border-top: 1px solid var(--ink); }
.catalog-aside { padding: 27px 28px 0 0; border-right: 1px solid var(--line); }
.catalog-aside h3 { margin: 12px 0 22px; font: 600 20px var(--serif); }
.index-list { padding: 0; margin: 0; list-style: none; }
.index-list li { display: grid; grid-template-columns: 48px 1fr; gap: 8px; padding: 11px 0; border-bottom: 1px solid var(--line); font-size: 13px; line-height: 1.6; }
.index-list li span { color: var(--accent); font: 10px var(--mono); }
.aside-note { margin: 26px 0 0; color: var(--muted); font-size: 12px; line-height: 1.8; }
.catalog-results { min-width: 0; padding-left: 30px; }
.result-label { display: flex; justify-content: space-between; gap: 15px; padding: 14px 0 13px; color: var(--muted); font: 11px var(--mono); }
.tutorial-grid { border-top: 1px solid var(--line); }
.tutorial-card {
  position: relative;
  display: grid;
  grid-template-columns: 52px minmax(0, 1fr) 36px;
  gap: 19px;
  align-items: center;
  min-height: 137px;
  padding: 21px 12px 21px 0;
  border-bottom: 1px solid var(--line);
  cursor: pointer;
  transition: background .18s ease, padding-left .18s ease;
}
.tutorial-card::before { content: ""; position: absolute; left: -30px; top: 0; bottom: 0; width: 3px; background: var(--card-accent, var(--blue)); opacity: 0; transition: opacity .18s ease; }
.tutorial-card:hover, .tutorial-card:focus-visible { padding-left: 12px; background: #ebe9e4; }
.tutorial-card:hover::before, .tutorial-card:focus-visible::before { opacity: 1; }
.tutorial-card:focus-visible { outline: 2px solid var(--blue); outline-offset: -2px; }
.card-index { align-self: start; color: var(--accent); font: 500 13px var(--mono); padding-top: 3px; }
.card-main { min-width: 0; }
.card-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 18px; }
.tutorial-card h3 { margin: 0; font: 700 23px/1.35 var(--serif); letter-spacing: -.045em; }
.card-tag { flex: none; color: var(--blue); font: 10px var(--mono); letter-spacing: .04em; text-transform: uppercase; }
.tutorial-card p { max-width: 680px; margin: 8px 0 12px; color: var(--muted); font-size: 14px; line-height: 1.75; }
.card-meta { display: flex; gap: 11px; color: #687587; font: 11px var(--mono); }
.card-arrow { color: var(--accent); font-size: 22px; text-align: right; transition: transform .18s ease; }
.tutorial-card:hover .card-arrow, .tutorial-card:focus-visible .card-arrow { transform: translateX(4px); }
.empty-state { margin: 30px 0; color: var(--muted); font-size: 13px; }

/* Format */
.format-section { padding-top: 105px; padding-bottom: 106px; background: var(--navy); color: #fff; }
.section-heading-light .section-kicker { color: #d6a99d; }
.section-heading-light .section-intro { color: #bec9d7; }
.format-list { border-top: 1px solid #607087; }
.format-row {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr) 100px;
  gap: 22px;
  align-items: center;
  padding: 24px 0;
  border-bottom: 1px solid #3d4d67;
}
.format-num { color: #d6a99d; font: 11px var(--mono); }
.format-row h3 { margin: 0 0 5px; font: 600 21px var(--serif); }
.format-row p { margin: 0; color: #cbd5e1; font-size: 14px; line-height: 1.8; }
.format-label { color: #c2cedc; font: 11px var(--mono); text-align: right; }
.format-note { display: flex; align-items: baseline; gap: 23px; padding-top: 24px; color: #e6edf4; font-size: 13px; }
.format-note span { color: #d6a99d; font: 10px var(--mono); white-space: nowrap; }
.format-note b { font-weight: 500; }

/* Teaching plan */
.plan-table { border-top: 1px solid var(--ink); }
.plan-row { display: grid; grid-template-columns: 92px 160px minmax(0, 1fr) 145px; gap: 22px; align-items: center; padding: 21px 0; border-bottom: 1px solid var(--line); font-size: 13px; }
.plan-row > span:first-child { color: var(--accent); font: 11px var(--mono); }
.plan-row strong { font-weight: 700; }
.plan-row > span:nth-child(3) { color: var(--muted); line-height: 1.75; }
.plan-row > span:last-child { color: var(--muted); font-size: 12px; }
.plan-head { padding: 12px 0; color: var(--muted); font: 11px var(--mono); }
.plan-head > span { color: var(--muted) !important; font: inherit !important; }
.plan-highlight { background: #f8e9e3; margin-inline: -14px; padding-inline: 14px; border-bottom-color: #e7c7bb; }

/* Student notes and footer */
.student-section { display: grid; grid-template-columns: .85fr 1.15fr; gap: 100px; align-items: start; padding-top: 16px; padding-bottom: 126px; }
.student-section::before { content: ""; grid-column: 1 / -1; border-top: 1px solid var(--line); margin-bottom: 74px; }
.student-intro h2 { margin: 14px 0 19px; font: 700 43px/1.15 var(--serif); letter-spacing: -.075em; }
.student-intro h2 em { color: var(--accent); font-style: normal; }
.student-intro p:not(.section-kicker) { max-width: 350px; margin: 0 0 17px; color: var(--muted); font-size: 14px; line-height: 1.9; }
.student-guidelines { border-top: 1px solid var(--line); }
.student-guidelines div { display: grid; grid-template-columns: 42px 1fr; gap: 20px; align-items: center; padding: 18px 0; border-bottom: 1px solid var(--line); }
.student-guidelines span { color: var(--accent); font: 10px var(--mono); }
.student-guidelines b { font-size: 14px; font-weight: 600; }
.site-footer { background: var(--navy); color: #c2cedc; }
.site-footer .wrap { display: flex; justify-content: space-between; gap: 30px; padding-top: 22px; padding-bottom: 25px; font: 11px var(--mono); letter-spacing: .03em; }
.site-footer i { color: #d6a99d; font-style: normal; }

/* Detail drawer */
.modal-backdrop { position: fixed; inset: 0; z-index: 10; display: flex; align-items: center; justify-content: center; padding: 48px; background: #16263fc9; }
.modal-backdrop[hidden] { display: none; }
.modal { position: relative; width: min(900px, calc(100% - 16px)); max-height: min(760px, calc(100vh - 96px)); overflow: auto; margin: 0 auto; padding: 42px 48px 36px; border: 1px solid #aeb6bf; border-top: 5px solid var(--accent); border-radius: 14px; background: var(--surface); box-shadow: 0 26px 90px #07101e66; }
.modal-close { float: right; width: 40px; height: 40px; margin: -12px -14px 15px 20px; border: 1px solid var(--line); background: transparent; color: var(--muted); cursor: pointer; font-size: 25px; line-height: 1; }
.modal-close:hover, .modal-close:focus-visible { border-color: var(--ink); color: var(--ink); }
.modal-top { display: flex; align-items: center; gap: 11px; clear: both; }
.modal-index { color: var(--accent); font: 11px var(--mono); }
.modal-category { color: var(--blue); font: 10px var(--mono); letter-spacing: .05em; text-transform: uppercase; }
.modal h2 { margin: 19px 0 9px; font: 700 36px/1.25 var(--serif); letter-spacing: -.065em; }
.modal-subtitle { margin: 0 0 28px; color: var(--muted); font-size: 15px; line-height: 1.8; }
.modal-objective { margin-bottom: 28px; padding: 16px 18px; border-left: 3px solid var(--accent); background: #fbf7f2; }
.modal-objective h4 { margin-bottom: 7px; color: var(--accent); }
.modal-objective p { margin: 0; color: var(--ink); font-size: 14px; line-height: 1.8; }
.modal-columns { display: grid; grid-template-columns: 1.1fr .9fr; gap: 34px; padding-top: 26px; border-top: 1px solid var(--line); }
.modal h4 { margin: 0 0 13px; color: var(--muted); font: 11px var(--mono); letter-spacing: .06em; text-transform: uppercase; }
.modal ul { padding: 0; margin: 0; list-style: none; }
.modal li { padding: 10px 0; border-bottom: 1px solid #e8eaeb; font-size: 14px; line-height: 1.65; }
.modal li::before { content: "—"; margin-right: 9px; color: var(--accent); }
.modal-paper { display: block; padding: 10px 0; border-bottom: 1px solid #e8eaeb; color: var(--ink); font-size: 13px; line-height: 1.5; }
.modal-paper::after { content: "↗"; float: right; color: var(--accent); font-size: 15px; }
.modal-paper:hover, .modal-paper:focus-visible { color: var(--blue); }
.modal-paper span { display: block; margin-top: 3px; color: var(--muted); font: 10px var(--mono); }
.modal h4.modal-h4-gap { margin-top: 26px; }
.modal-columns p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.8; }
.modal-footer { display: flex; gap: 9px; margin-top: 34px; padding-top: 17px; border-top: 1px solid var(--line); color: var(--muted); font: 10px var(--mono); }
.modal-footer span + span::before { content: "·"; margin: 0 9px; color: var(--accent); }

@media (max-width: 900px) {
  .wrap { width: min(var(--wrap), calc(100% - 44px)); }
  .header-main { gap: 20px; }
  .main-nav { gap: 20px; }
  .hero { grid-template-columns: 1fr; gap: 48px; padding-top: 62px; padding-bottom: 62px; }
  .overview-panel { max-width: 620px; }
  .catalog-layout { grid-template-columns: 1fr; }
  .catalog-aside { padding: 25px 0 24px; border-right: 0; border-bottom: 1px solid var(--line); }
  .index-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 24px; }
  .catalog-results { padding-left: 0; }
  .student-section { gap: 55px; }
}

@media (max-width: 680px) {
  .wrap { width: min(var(--wrap), calc(100% - 30px)); }
  .topline-inner { min-height: 36px; font-size: 9px; }
  .topline-inner span:last-child { text-align: right; }
  .header-main { min-height: 75px; }
  .brand { min-width: 0; }
  .brand-kicker { font-size: 8px; }
  .brand-title { font-size: 19px; }
  .main-nav { display: none; }
  .header-action { padding: 8px 10px; font-size: 11px; }
  .hero h1 { font-size: clamp(43px, 13vw, 63px); }
  .hero-lead { font-size: 15px; line-height: 1.9; }
  .hero-meta { grid-template-columns: 1fr; }
  .hero-meta div, .hero-meta div + div { padding: 13px 0; border-right: 0; border-bottom: 1px solid var(--line); }
  .hero-meta div:last-child { border-bottom: 0; }
  .notice { grid-template-columns: 1fr; gap: 8px; padding: 17px 0; }
  .notice a { justify-self: start; }
  .section { padding-top: 78px; padding-bottom: 80px; }
  .section-heading { display: block; margin-bottom: 31px; }
  .section-intro { margin-top: 18px; }
  .toolbar { display: block; }
  .search-box { width: 100%; margin-bottom: 12px; }
  .filters { justify-content: flex-start; }
  .filter { flex: 1 1 auto; padding-inline: 8px; }
  .index-list { grid-template-columns: 1fr; }
  .tutorial-card { grid-template-columns: 35px minmax(0, 1fr) 24px; gap: 10px; min-height: 0; padding-block: 20px; }
  .tutorial-card:hover, .tutorial-card:focus-visible { padding-left: 8px; }
  .tutorial-card::before { left: -15px; }
  .card-heading { display: block; }
  .card-tag { display: block; margin-bottom: 6px; font-size: 9px; }
  .tutorial-card h3 { font-size: 18px; }
  .tutorial-card p { font-size: 13px; }
  .format-section { padding-top: 78px; padding-bottom: 78px; }
  .format-row { grid-template-columns: 35px minmax(0, 1fr); gap: 11px; padding-block: 21px; }
  .format-label { grid-column: 2; text-align: left; color: #d6a99d; }
  .format-note { display: block; line-height: 1.8; }
  .format-note b { display: block; margin-top: 8px; font-size: 13px; }
  .plan-row { grid-template-columns: 70px 1fr; gap: 8px 14px; padding-block: 18px; }
  .plan-row > span:nth-child(3), .plan-row > span:last-child { grid-column: 2; }
  .plan-head { display: none; }
  .plan-highlight { margin-inline: -8px; padding-inline: 8px; }
  .student-section { grid-template-columns: 1fr; gap: 42px; padding-bottom: 85px; }
  .student-section::before { margin-bottom: 38px; }
  .student-intro h2 { font-size: 38px; }
  .site-footer .wrap { display: block; }
  .site-footer .wrap span { display: block; margin: 5px 0; }
  .modal-backdrop { padding: 16px; }
  .modal { width: 100%; max-height: calc(100vh - 32px); padding: 31px 25px 28px; border-top-width: 3px; border-radius: 11px; }
  .modal h2 { font-size: 29px; }
  .modal-columns { grid-template-columns: 1fr; gap: 28px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; }
}