:root {
  --paper: #F6F1E7;
  --paper-deep: #E9E1D0;
  --white: #FFFCF5;
  --ink: #17324D;
  --ink-soft: #496072;
  --teal: #147D74;
  --teal-light: #D5EAE5;
  --gold: #D18B2C;
  --gold-light: #F4E3B3;
  --coral: #C95745;
  --coral-light: #F3D7D0;
  --line: #B9B09F;
  --display: "Noto Serif CJK SC", "Source Han Serif SC", "SimSun", serif;
  --body: "Noto Sans CJK SC", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }

html { background: var(--paper); color: var(--ink); }

body {
  margin: 0;
  min-width: 320px;
  background:
    linear-gradient(90deg, rgba(23, 50, 77, .045) 1px, transparent 1px),
    linear-gradient(rgba(23, 50, 77, .045) 1px, transparent 1px),
    var(--paper);
  background-size: 28px 28px;
  font-family: var(--body);
}

a { color: inherit; }

button, select { font: inherit; }

button, .primary-links a, .file-tools a {
  min-height: 42px;
  border: 1px solid var(--ink);
  color: var(--ink);
  background: transparent;
  cursor: pointer;
}

button:hover, .primary-links a:hover, .file-tools a:hover {
  color: var(--white);
  background: var(--ink);
}

button:focus-visible, a:focus-visible, select:focus-visible {
  outline: 3px solid var(--coral);
  outline-offset: 3px;
}

.skip-link {
  position: absolute;
  left: 16px;
  top: -80px;
  z-index: 20;
  padding: 10px 14px;
  color: var(--white);
  background: var(--ink);
}

.skip-link:focus { top: 14px; }

.masthead {
  display: grid;
  grid-template-columns: 170px minmax(420px, 1fr) 340px;
  gap: 32px;
  min-height: 300px;
  padding: 34px 46px 28px;
  border-top: 14px solid var(--teal);
  border-bottom: 2px solid var(--ink);
  background: rgba(255, 252, 245, .84);
}

.edition {
  align-self: stretch;
  display: grid;
  grid-template-rows: auto 1fr auto;
  padding: 14px 12px;
  border-right: 1px solid var(--ink);
}

.edition-kicker, .edition-label, .eyebrow, .plate-kicker, .index-heading p {
  margin: 0;
  color: var(--coral);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .16em;
}

.edition-number {
  align-self: center;
  font: 500 clamp(72px, 8vw, 132px)/.8 var(--display);
  color: var(--gold);
}

.title-block { align-self: end; max-width: 820px; }

.title-block h1 {
  margin: 14px 0 18px;
  font: 500 clamp(48px, 5vw, 86px)/.92 var(--display);
  letter-spacing: -.045em;
}

.title-block h1 span { color: var(--teal); }

.title-block > p:last-child {
  max-width: 680px;
  margin: 0 0 4px 12%;
  color: var(--ink-soft);
  font: 400 15px/1.8 var(--body);
}

.primary-links {
  align-self: end;
  display: grid;
  gap: 9px;
}

.primary-links a, .file-tools a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  text-decoration: none;
}

svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; }

.atlas-shell {
  display: grid;
  grid-template-columns: 310px minmax(0, 1fr);
  min-height: 740px;
}

.chapter-index {
  position: relative;
  z-index: 2;
  padding: 34px 24px 42px 38px;
  border-right: 2px solid var(--ink);
  background: rgba(233, 225, 208, .82);
}

.index-heading h2, .viewer-header h2 {
  margin: 6px 0 0;
  font: 500 30px/1.15 var(--display);
}

.plate-list {
  display: grid;
  gap: 2px;
  margin-top: 28px;
}

.plate-button {
  position: relative;
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 10px;
  width: 100%;
  min-height: 58px;
  padding: 8px 10px;
  border-width: 0 0 1px;
  border-color: var(--line);
  text-align: left;
}

.plate-button:hover { background: var(--white); color: var(--ink); }

.plate-button[aria-pressed="true"] {
  color: var(--white);
  background: var(--ink);
}

.plate-button[aria-pressed="true"]::before {
  content: "";
  position: absolute;
  left: -14px;
  top: 0;
  width: 8px;
  height: 100%;
  background: var(--coral);
}

.plate-code { color: var(--coral); font-size: 12px; font-weight: 700; letter-spacing: .08em; }

.plate-name { font-family: var(--display); font-size: 14px; font-weight: 500; }

.plate-button[aria-pressed="true"] .plate-code { color: var(--gold-light); }

.legend-panel {
  margin: 36px 0 0 20px;
  padding: 18px 0 0 18px;
  border-left: 4px solid var(--gold);
}

.legend-panel h3 { margin: 0 0 12px; font: 500 18px/1.2 var(--display); }

.legend-panel dl, .legend-panel dt, .legend-panel dd { margin: 0; }

.legend-panel dl > div { margin: 0 0 11px; }

.legend-panel dt { display: flex; align-items: center; gap: 8px; font-size: 12px; font-weight: 700; }

.legend-panel dd { margin: 3px 0 0 24px; color: var(--ink-soft); font-size: 11px; }

.swatch { display: inline-block; width: 16px; height: 11px; border: 2px solid; }
.swatch.theorem { background: var(--gold-light); border-color: var(--gold); clip-path: polygon(15% 0,85% 0,100% 50%,85% 100%,15% 100%,0 50%); }
.swatch.concept { background: var(--teal-light); border-color: var(--teal); border-radius: 5px; }
.swatch.boundary { background: var(--coral-light); border-color: var(--coral); border-style: dashed; }
.swatch.core { height: 5px; background: var(--gold); border: 0; }

.viewer {
  min-width: 0;
  padding: 30px 38px 42px;
  background: rgba(246, 241, 231, .92);
}

.viewer-header {
  display: grid;
  grid-template-columns: 1fr minmax(220px, 320px);
  gap: 32px;
  align-items: end;
  padding-left: 28px;
  border-left: 8px solid var(--gold);
}

.viewer-header h2 { font-size: 38px; }

.viewer-header > div > p:last-child {
  max-width: 760px;
  margin: 10px 0 0;
  color: var(--ink-soft);
  font-size: 14px;
  line-height: 1.6;
}

.select-wrap { display: grid; gap: 7px; color: var(--ink-soft); font-size: 11px; font-weight: 700; letter-spacing: .08em; }

.select-wrap select {
  min-height: 44px;
  width: 100%;
  padding: 9px 34px 9px 11px;
  border: 1px solid var(--ink);
  border-radius: 0;
  color: var(--ink);
  background: var(--white);
}

.viewer-tools {
  display: grid;
  grid-template-columns: auto auto 1fr;
  gap: 12px;
  align-items: center;
  margin: 26px 0 14px;
  padding: 10px;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  background: rgba(255, 252, 245, .78);
}

.step-tools, .zoom-tools, .file-tools { display: flex; flex-wrap: wrap; gap: 7px; }

.file-tools { justify-content: end; }

.viewer-tools button, .viewer-tools a { padding: 8px 11px; text-decoration: none; }

.viewer-tools button { display: inline-flex; align-items: center; justify-content: center; gap: 7px; }

.zoom-tools output {
  display: inline-grid;
  place-items: center;
  min-width: 58px;
  color: var(--ink-soft);
  font-variant-numeric: tabular-nums;
}

#zoomIn, #zoomOut { width: 42px; padding: 0; font-size: 19px; }

.atlas-canvas {
  max-width: 100%;
  min-height: 460px;
  overflow: auto;
  border: 2px solid var(--ink);
  background: var(--paper);
  scrollbar-color: var(--teal) var(--paper-deep);
}

.atlas-canvas object { display: block; min-width: 100%; background: var(--paper); }

.load-status {
  margin: 8px 0 0;
  color: var(--ink-soft);
  font-size: 12px;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 20px 42px;
  color: var(--white);
  background: var(--ink);
  font-size: 12px;
}

footer p { margin: 0; }

@media (max-width: 1120px) {
  .masthead { grid-template-columns: 125px 1fr; }
  .primary-links { grid-column: 2; grid-template-columns: repeat(3, 1fr); }
  .atlas-shell { grid-template-columns: 250px minmax(0, 1fr); }
  .chapter-index { padding-left: 24px; }
  .viewer-tools { grid-template-columns: 1fr 1fr; }
  .file-tools { grid-column: 1 / -1; justify-content: start; }
}

@media (max-width: 820px) {
  .masthead { grid-template-columns: 88px 1fr; padding: 24px 20px; }
  .edition-number { font-size: 64px; }
  .title-block h1 { font-size: 48px; }
  .title-block > p:last-child { margin-left: 0; }
  .primary-links { grid-column: 1 / -1; grid-template-columns: 1fr; }
  .atlas-shell { display: block; }
  .chapter-index { border-right: 0; border-bottom: 2px solid var(--ink); padding: 24px 18px; }
  .plate-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .legend-panel { display: none; }
  .viewer { padding: 26px 18px 34px; }
  .viewer-header { grid-template-columns: 1fr; }
  .viewer-tools { display: flex; flex-wrap: wrap; }
  .file-tools { justify-content: start; }
  .atlas-canvas { min-height: 300px; }
  footer { display: grid; }
}

@media (max-width: 480px) {
  .masthead { grid-template-columns: 1fr; }
  .edition { display: flex; align-items: baseline; gap: 12px; border-right: 0; border-bottom: 1px solid var(--ink); }
  .edition-number { font-size: 44px; }
  .title-block h1 { font-size: 41px; }
  .plate-list { grid-template-columns: 1fr; }
  .viewer-header { padding-left: 16px; }
  .viewer-header h2 { font-size: 30px; }
  .viewer-tools { align-items: stretch; }
  .step-tools, .zoom-tools, .file-tools { width: 100%; }
  .viewer-tools button, .viewer-tools a { flex: 1 1 auto; }
}

@media print {
  .masthead, .chapter-index, .viewer-header, .viewer-tools, .load-status, footer { display: none !important; }
  .atlas-shell, .viewer { display: block; padding: 0; }
  .atlas-canvas { border: 0; overflow: visible; }
  .atlas-canvas object { width: 100% !important; height: auto !important; }
}