/* Shared course navigation and reading enhancements. */
:root {
  --course-ink: #1b1a17;
  --course-muted: #6d6962;
  --course-line: rgba(27, 26, 23, 0.14);
  --course-line-strong: rgba(27, 26, 23, 0.3);
  --course-accent: #4338ca;
  --course-accent-soft: #eceaff;
  --course-paper: #faf9f6;
}

html {
  overflow-x: hidden;
}

body.course-lesson {
  color: var(--course-ink);
  background: var(--course-paper);
}

body.course-lesson .course-topbar {
  position: sticky;
  z-index: 80;
  top: 0;
  border-bottom: 1px solid var(--course-line);
  background: rgba(250, 249, 246, 0.94);
  box-shadow: none;
  backdrop-filter: blur(16px);
}

body.course-lesson .course-topbar .brand {
  font-weight: 600;
}

body.course-lesson .course-topbar ul.tabs {
  scrollbar-width: thin;
}

body.course-lesson .lesson-header {
  position: relative;
  color: var(--course-ink);
  border-bottom: 1px solid var(--course-line);
  background:
    linear-gradient(90deg, transparent 0 71%, rgba(67, 56, 202, 0.055) 71% 100%),
    var(--course-paper);
}

body.course-lesson .lesson-header .subtitle,
body.course-lesson .lesson-header .header-tip {
  color: var(--course-muted);
}

body.course-lesson .lesson-header .kbd {
  color: var(--course-ink);
  border: 1px solid var(--course-line);
  background: #fff;
}

body.course-lesson .lesson-main {
  gap: 28px;
}

body.course-lesson .chapter-nav {
  top: 78px;
  border-color: var(--course-line);
  border-radius: 3px;
  box-shadow: 0 16px 42px rgba(27, 26, 23, 0.045);
}

body.course-lesson .chapter-nav a {
  border-radius: 2px;
}

body.course-lesson .chapter-nav a.active {
  color: var(--course-accent);
  border-left-color: var(--course-accent);
  background: var(--course-accent-soft);
}

body.course-lesson .chapter-content {
  border-color: var(--course-line);
  border-radius: 3px;
  box-shadow: 0 20px 60px rgba(27, 26, 23, 0.055);
}

body.course-lesson .chapter:not(.active) {
  display: none;
}

body.course-lesson .chapter.active {
  scroll-margin-top: 86px;
}

body.course-lesson .chapter h2 {
  font-family: "Songti SC", "STSong", Georgia, serif;
  font-weight: 600;
}

body.course-lesson .tabs {
  gap: 2px;
  border-bottom-color: var(--course-line);
}

body.course-lesson .tab-btn {
  border-radius: 2px 2px 0 0;
}

body.course-lesson .tab-btn.active {
  color: var(--course-accent);
  border-bottom-color: var(--course-accent);
  background: var(--course-accent-soft);
}

body.course-lesson .key-point,
body.course-lesson .note {
  border-radius: 2px;
}

body.course-lesson .code-purpose {
  padding: 10px 14px;
  border-left-color: var(--course-accent);
  background: rgba(67, 56, 202, 0.055);
}

body.course-lesson pre {
  position: relative;
  margin-top: 34px;
  border-radius: 3px;
}

/* Keep dense teaching graphics readable instead of shrinking labels below a
   usable size. Only the visualization or table scrolls, never the page. */
.demo-mount,
.chart-scroller,
.table-scroller,
.data-shape-grid > div {
  min-width: 0;
}

.chart-scroller,
.table-scroller {
  max-width: 100%;
  overflow-x: auto;
  overscroll-behavior-inline: contain;
  scrollbar-gutter: stable;
  -webkit-overflow-scrolling: touch;
}

.chart-scroller {
  padding-bottom: 7px;
}

.chart-scroller:focus-visible,
.table-scroller:focus-visible {
  outline: 2px solid var(--course-accent);
  outline-offset: 2px;
}

.chart-scroller > svg {
  flex: 0 0 auto;
  max-width: none !important;
}

.table-scroller > table {
  width: max-content;
  min-width: 100%;
  max-width: none;
}

.data-shape-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 12px;
  margin: 8px 0;
}

.demo-two-column {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.data-shape-grid pre {
  max-width: 100%;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.chart-scroller > #d-4-1-svg {
  width: 920px;
  height: 200px;
}

.chart-scroller > #d-4-3-svg {
  width: 800px;
  height: 360px;
}

#d-3-2-svg .chart-scroller > svg,
.demo-sub .chart-scroller > svg {
  width: 600px;
  height: auto;
}

@media (max-width: 1000px) {
  .harmony-grid {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  }

  .cvd-paper {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .color-grid,
  .cvd-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .color-space-cards,
  .quiz-grid,
  .philosophy-row,
  .philosophy-paper,
  .data-shape-grid,
  .demo-two-column {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .color-picker-row input[type="range"] {
    width: 100%;
  }

  .palette-matrix {
    grid-template-columns: minmax(0, 1fr);
  }

  .palette-source {
    grid-column: 1;
  }

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

  .slope-control,
  .ms-threshold-control,
  .cal-legend-bar {
    flex-wrap: wrap;
  }

  .slope-control input[type="range"],
  .ms-threshold-control input[type="range"] {
    flex: 1 1 180px;
    min-width: 140px;
    width: auto;
  }

  .legend-strip {
    min-width: 180px;
  }

  .cvd-paper-card > div[style*="grid-template-columns"] {
    grid-template-columns: minmax(0, 1fr) !important;
  }

  .cvd-paper-card svg {
    width: min(100%, 260px);
    height: auto;
  }

  .quiz-card svg {
    width: 100%;
    height: auto;
  }

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

.copy-code {
  position: absolute;
  z-index: 2;
  top: 8px;
  right: 8px;
  padding: 4px 8px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #dce5e6;
  background: rgba(15, 23, 42, 0.82);
  font-family: "PingFang SC", sans-serif;
  font-size: 10px;
  cursor: pointer;
}

.copy-code:hover {
  border-color: rgba(255, 255, 255, 0.48);
  color: #fff;
}

.course-progress-line {
  position: fixed;
  z-index: 120;
  top: 0;
  right: 4px;
  left: 0;
  height: 3px;
  pointer-events: none;
}

.course-progress-line span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--course-accent);
}

.course-context {
  position: fixed;
  z-index: 70;
  right: 22px;
  bottom: 22px;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 11px;
  border: 1px solid var(--course-line);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.94);
  box-shadow: 0 8px 26px rgba(27, 26, 23, 0.12);
  font: 11px/1.2 "PingFang SC", sans-serif;
}

.course-context a {
  color: var(--course-accent);
  text-decoration: none;
}

.course-context .context-separator {
  width: 1px;
  height: 13px;
  background: var(--course-line);
}

.course-context button {
  padding: 0;
  border: 0;
  color: var(--course-ink);
  background: transparent;
  cursor: pointer;
}

@media (max-width: 820px) {
  body.course-lesson {
    padding-bottom: 72px;
  }

  body.course-lesson .course-topbar {
    display: grid;
    grid-template-columns: auto 1fr auto;
    align-items: center;
    gap: 8px 12px;
    padding: 9px 12px;
  }

  body.course-lesson .course-topbar .brand {
    grid-column: 1;
    grid-row: 1;
  }

  body.course-lesson .course-topbar .lang-switch {
    grid-column: 3;
    grid-row: 1;
  }

  body.course-lesson .course-topbar ul.tabs {
    grid-column: 1 / -1;
    grid-row: 2;
    width: 100%;
  }

  body.course-lesson .lesson-header .header-tip {
    display: none;
  }

  body.course-lesson .course-topbar ul.tabs li:first-child {
    display: none;
  }

  body.course-lesson .lesson-main {
    display: block;
    padding: 18px;
  }

  body.course-lesson .chapter-nav {
    position: static;
    margin-bottom: 18px;
  }

  body.course-lesson .chapter-nav ul {
    display: flex;
    gap: 6px;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  body.course-lesson .chapter-nav li {
    flex: 0 0 auto;
    margin: 0;
  }

  body.course-lesson .chapter-nav a {
    white-space: nowrap;
  }

  body.course-lesson .chapter {
    padding: 24px 20px 28px;
  }

  body.course-lesson .course-context {
    position: static;
    justify-content: flex-end;
    margin: 0 18px 18px;
    border-radius: 2px;
  }
}

@media print {
  body.course-lesson .course-topbar,
  body.course-lesson .chapter-nav,
  body.course-lesson .course-context,
  body.course-lesson .chapter-pager,
  body.course-lesson .copy-code {
    display: none !important;
  }
}