:root {
  --bg: #020202;
  --bg-elevated: #090909;
  --panel: #0d0d0d;
  --panel-strong: #121212;
  --ink: #f4f4f4;
  --muted: #a3a3a3;
  --line: #252525;
  --line-strong: #454545;
  --accent: #f4f4f4;
  --accent-soft: rgba(255, 255, 255, 0.08);
  --warn: #d88383;
  --page-grid-rgb: 255, 255, 255;
  --page-grid-alpha: 0.018;
  --page-start: #010101;
  --page-end: #050505;
  --page-glow-a: rgba(255, 255, 255, 0.035);
  --page-glow-b: rgba(255, 255, 255, 0.025);
  --topbar-start: #0c0c0c;
  --topbar-end: #080808;
  --sidebar-start: #101010;
  --sidebar-end: #0a0a0a;
  --runner-start: #121212;
  --runner-end: #0d0d0d;
  --settings-start: #111111;
  --settings-end: #090909;
  --card-bg: rgba(255, 255, 255, 0.025);
  --tree-hover-bg: rgba(255, 255, 255, 0.03);
  --editor-bg: #060606;
  --backdrop: rgba(0, 0, 0, 0.72);
  --danger-start: rgba(58, 24, 24, 0.22);
  --danger-end: rgba(18, 10, 10, 0.96);
  --danger-border: rgba(217, 143, 115, 0.55);
  --danger-text: #f5c7b9;
  --mono: "JetBrains Mono", "IBM Plex Mono", "Fira Code", "SFMono-Regular", Menlo, Consolas, monospace;
  --serif: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Georgia, serif;
  color-scheme: dark;
}

:root[data-theme="dark"] {
  color-scheme: dark;
}

:root[data-theme="light"] {
  --bg: #f3f3f3;
  --bg-elevated: #fcfcfc;
  --panel: #ffffff;
  --panel-strong: #f6f6f6;
  --ink: #111111;
  --muted: #5d5d5d;
  --line: #d9d9d9;
  --line-strong: #b8b8b8;
  --accent: #111111;
  --accent-soft: rgba(0, 0, 0, 0.05);
  --warn: #9e4f4f;
  --page-grid-rgb: 0, 0, 0;
  --page-grid-alpha: 0.04;
  --page-start: #fafafa;
  --page-end: #ececec;
  --page-glow-a: rgba(0, 0, 0, 0.035);
  --page-glow-b: rgba(0, 0, 0, 0.025);
  --topbar-start: #ffffff;
  --topbar-end: #f0f0f0;
  --sidebar-start: #fcfcfc;
  --sidebar-end: #f2f2f2;
  --runner-start: #ffffff;
  --runner-end: #f5f5f5;
  --settings-start: #ffffff;
  --settings-end: #f2f2f2;
  --card-bg: rgba(0, 0, 0, 0.02);
  --tree-hover-bg: rgba(0, 0, 0, 0.04);
  --editor-bg: #ffffff;
  --backdrop: rgba(16, 16, 16, 0.38);
  --danger-start: rgba(176, 74, 74, 0.08);
  --danger-end: rgba(255, 255, 255, 0.96);
  --danger-border: rgba(158, 79, 79, 0.42);
  --danger-text: #7a2d2d;
  color-scheme: light;
}

@media (prefers-color-scheme: light) {
  :root[data-theme="system"] {
    --bg: #f3f3f3;
    --bg-elevated: #fcfcfc;
    --panel: #ffffff;
    --panel-strong: #f6f6f6;
    --ink: #111111;
    --muted: #5d5d5d;
    --line: #d9d9d9;
    --line-strong: #b8b8b8;
    --accent: #111111;
    --accent-soft: rgba(0, 0, 0, 0.05);
    --warn: #9e4f4f;
    --page-grid-rgb: 0, 0, 0;
    --page-grid-alpha: 0.04;
    --page-start: #fafafa;
    --page-end: #ececec;
    --page-glow-a: rgba(0, 0, 0, 0.035);
    --page-glow-b: rgba(0, 0, 0, 0.025);
    --topbar-start: #ffffff;
    --topbar-end: #f0f0f0;
    --sidebar-start: #fcfcfc;
    --sidebar-end: #f2f2f2;
    --runner-start: #ffffff;
    --runner-end: #f5f5f5;
    --settings-start: #ffffff;
    --settings-end: #f2f2f2;
    --card-bg: rgba(0, 0, 0, 0.02);
    --tree-hover-bg: rgba(0, 0, 0, 0.04);
    --editor-bg: #ffffff;
    --backdrop: rgba(16, 16, 16, 0.38);
    --danger-start: rgba(176, 74, 74, 0.08);
    --danger-end: rgba(255, 255, 255, 0.96);
    --danger-border: rgba(158, 79, 79, 0.42);
    --danger-text: #7a2d2d;
    color-scheme: light;
  }
}

* {
  box-sizing: border-box;
}

html {
  height: 100%;
  background:
    linear-gradient(90deg, rgba(var(--page-grid-rgb), var(--page-grid-alpha)) 1px, transparent 1px),
    linear-gradient(rgba(var(--page-grid-rgb), var(--page-grid-alpha)) 1px, transparent 1px),
    linear-gradient(180deg, var(--page-start) 0%, var(--page-end) 100%);
  background-size: 28px 28px, 28px 28px, auto;
  color: var(--ink);
}

body {
  margin: 0;
  min-height: 100vh;
  height: 100%;
  background:
    radial-gradient(circle at top right, var(--page-glow-a), transparent 18%),
    radial-gradient(circle at bottom left, var(--page-glow-b), transparent 24%);
  color: var(--ink);
  font-family: var(--mono);
}

#app {
  height: 100vh;
  padding: 24px;
  overflow: hidden;
}

.reference-shell {
  height: 100%;
  max-width: 1560px;
  margin: 0 auto;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: 18px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 68px;
  padding: 0 24px;
  border: 1px solid var(--line-strong);
  background: linear-gradient(180deg, var(--topbar-start), var(--topbar-end));
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.topbar-button,
.settings-close-button {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  font: inherit;
  font-family: var(--mono);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  cursor: pointer;
  padding: 10px 14px;
  text-decoration: none;
  transition:
    border-color 140ms ease,
    background 140ms ease,
    transform 140ms ease;
}

.topbar-button:hover,
.settings-close-button:hover {
  border-color: var(--accent);
  background: var(--accent-soft);
  transform: translateY(-1px);
}

.topbar-brand,
.module-kicker,
.result-label,
.meta-label,
.nav-meta,
.parser-state {
  margin: 0;
  font-family: var(--mono);
  font-size: 0.76rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.topbar-brand,
.module-kicker,
.result-label,
.meta-label,
.parser-state {
  color: var(--accent);
}

.reference-layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: 18px;
  min-height: 0;
  overflow: hidden;
}

.sidebar,
.content-column {
  display: grid;
  gap: 18px;
  align-content: start;
  min-height: 0;
  overflow-y: auto;
  padding-right: 6px;
  scrollbar-width: thin;
  scrollbar-color: var(--line-strong) transparent;
}

.sidebar::-webkit-scrollbar,
.content-column::-webkit-scrollbar {
  width: 10px;
}

.sidebar::-webkit-scrollbar-thumb,
.content-column::-webkit-scrollbar-thumb {
  background: var(--line-strong);
  border: 2px solid transparent;
  background-clip: padding-box;
}

.sidebar::-webkit-scrollbar-track,
.content-column::-webkit-scrollbar-track {
  background: transparent;
}

.panel {
  padding: 24px;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, var(--panel-strong), var(--panel));
}

.panel h2 {
  margin: 0;
  font-size: 1.18rem;
  letter-spacing: -0.02em;
}

.panel-copy,
.article-copy,
.example-description,
.toolbar-hint,
.nav-subtitle,
.function-signature,
.example-copy,
.function-signature-line {
  color: var(--muted);
  line-height: 1.65;
  font-family: var(--mono);
}

.sidebar-panel {
  background: linear-gradient(180deg, var(--sidebar-start), var(--sidebar-end));
}

.nav-stack,
.function-grid,
.example-grid,
.parser-grid,
.result-grid,
.meta-grid {
  display: grid;
  gap: 12px;
}

.nav-stack {
  margin-top: 18px;
}

.nav-button,
.function-button,
.example-button,
.parser-button,
.run-button {
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  font: inherit;
  cursor: pointer;
  text-align: left;
  transition:
    border-color 140ms ease,
    background 140ms ease,
    color 140ms ease,
    transform 140ms ease;
}

.nav-button:hover,
.function-button:hover,
.example-button:hover,
.parser-button:hover,
.run-button:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.nav-button {
  display: grid;
  gap: 6px;
  padding: 14px 16px;
}

.nav-node {
  display: grid;
  gap: 8px;
}

.nav-title-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-chevron {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1rem;
  font-family: var(--mono);
  color: var(--accent);
}

.nav-children {
  display: grid;
  gap: 8px;
  padding-left: 18px;
  border-left: 1px solid var(--line);
}

.nav-children-hidden {
  display: none;
}

.nav-button-active,
.function-button-active,
.example-button-active,
.parser-button-active {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.nav-title,
.function-name,
.example-title {
  font-size: 1rem;
  font-weight: 700;
}

.nav-subtitle,
.nav-meta,
.function-topic,
.function-signature,
.example-copy {
  font-family: var(--mono);
  font-size: 0.82rem;
}

.function-topic {
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

.tree-function-button {
  border: 1px solid transparent;
  background: transparent;
  color: var(--muted);
  font: inherit;
  cursor: pointer;
  text-align: left;
  padding: 8px 10px;
  transition:
    border-color 140ms ease,
    background 140ms ease,
    color 140ms ease;
}

.tree-function-button:hover {
  color: var(--ink);
  border-color: var(--line);
  background: var(--tree-hover-bg);
}

.tree-function-button-active {
  color: var(--ink);
  border-color: var(--accent);
  background: var(--accent-soft);
}

.tree-function-name {
  font-family: var(--mono);
  font-size: 0.84rem;
  line-height: 1.4;
}

.sidebar-note,
.architecture-block,
.meta-value,
.result-value,
.latex-source,
.error-block {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: var(--mono);
  line-height: 1.72;
  font-size: 0.91rem;
}

.runner-panel {
  background: linear-gradient(180deg, var(--runner-start), var(--runner-end));
}

.settings-modal-hidden {
  display: none;
}

.settings-backdrop {
  position: fixed;
  inset: 0;
  z-index: 30;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  background: var(--backdrop);
}

.settings-dialog {
  width: min(760px, 100%);
  max-height: min(80vh, 720px);
  overflow-y: auto;
  border-color: var(--line-strong);
  background: linear-gradient(180deg, var(--settings-start), var(--settings-end));
}

.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.settings-section {
  display: grid;
  gap: 12px;
  margin-bottom: 18px;
}

.settings-parser-grid {
  margin-top: 0;
}

.section-heading {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: baseline;
  margin-bottom: 14px;
}

.section-heading small {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.82rem;
}

.result-card {
  min-width: 0;
  padding: 16px;
  border: 1px solid var(--line);
  background: var(--card-bg);
}

.result-label {
  margin-bottom: 10px;
}

.result-value-latex-shell {
  min-width: 0;
}

.result-value,
.result-value-latex-shell {
  overflow-x: auto;
}

.plot-result-shell {
  display: grid;
  gap: 12px;
}

.plot-svg {
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.025), transparent),
    var(--editor-bg);
  color: var(--ink);
}

.plot-frame {
  opacity: 0.55;
}

.plot-axis {
  opacity: 0.28;
}

.plot-line {
  color: var(--ink);
}

.plot-point {
  color: var(--ink);
}

.plot-region {
  color: var(--ink);
}

.plot-caption {
  margin-top: 0;
}

.plot-empty {
  padding: 18px;
  border: 1px solid var(--line);
  color: var(--muted);
  font-family: var(--mono);
  line-height: 1.6;
}

.latex-source,
.latex-render {
  display: none;
}

.result-value-latex-shell.katex-ready .latex-fallback {
  display: none;
}

.result-value-latex-shell.katex-ready .latex-render {
  display: block;
  overflow-x: auto;
  padding: 4px 0;
}

.result-value-latex-shell.katex-failed .latex-fallback {
  display: block;
}

.result-value-latex-shell .katex {
  color: var(--ink);
  font-size: 1.03em;
}

.result-value-latex-shell .katex-display {
  margin: 0;
}

.result-value-latex-shell .katex-display > .katex {
  text-align: left;
}

.function-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.function-button,
.example-button {
  display: grid;
  gap: 8px;
  padding: 16px;
}

.editor-area {
  width: 100%;
  min-height: 240px;
  padding: 18px;
  border: 1px solid var(--line-strong);
  background: var(--editor-bg);
  color: var(--ink);
  resize: vertical;
  font-family: var(--mono);
  font-size: 0.95rem;
  line-height: 1.7;
}

.example-description {
  margin: 10px 0 0;
}

.parser-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  margin-top: 14px;
}

.parser-button {
  display: flex;
  gap: 12px;
  align-items: center;
  min-height: 58px;
  padding: 12px 14px;
}

.parser-state {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 42px;
  padding: 6px 8px;
  border: 1px solid var(--line-strong);
}

.parser-copy {
  line-height: 1.4;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  align-items: flex-start;
  margin-top: 18px;
}

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

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

.panel-danger {
  border-color: var(--danger-border);
  background: linear-gradient(180deg, var(--danger-start), var(--danger-end));
}

.error-block {
  margin-top: 16px;
  padding: 16px;
  border: 1px solid var(--danger-border);
  color: var(--danger-text);
}

@media (max-width: 1120px) {
  #app {
    padding: 18px;
    height: auto;
    min-height: 100vh;
    overflow: visible;
  }

  .reference-layout {
    grid-template-columns: 1fr;
  }

  .reference-shell {
    height: auto;
    grid-template-rows: auto auto;
  }

  .sidebar,
  .content-column {
    overflow: visible;
    padding-right: 0;
  }
}

@media (max-width: 720px) {
  .panel {
    padding: 18px;
  }

  .function-grid,
  .example-grid,
  .parser-grid,
  .result-grid,
  .result-grid-2,
  .result-grid-3 {
    grid-template-columns: 1fr;
  }
}