:root {
  --bg: #0a0d12;
  --bg-elevated: #10151d;
  --bg-panel: #121923;
  --bg-panel-2: #0f141c;
  --bg-code: #0b1017;
  --ink: #e6ebf2;
  --ink-soft: #b5c0cf;
  --ink-dim: #7f8b9c;
  --line: rgba(191, 205, 224, 0.14);
  --line-strong: rgba(191, 205, 224, 0.24);
  --accent: #9cc6ff;
  --accent-2: #7ee0c2;
  --accent-3: #ffcb8a;
  --section-color: #d9e5f8;
  --subsection-color: #8fd8c3;
  --subsubsection-color: #f0c48d;
  --shadow: 0 18px 60px rgba(0, 0, 0, 0.32);
  --body-font: "Aptos", "Segoe UI Variable", "Helvetica Neue", "Nimbus Sans", sans-serif;
  --title-font: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", serif;
  --mono-font: "Berkeley Mono", "Cascadia Code", "SFMono-Regular", Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(126, 224, 194, 0.07), transparent 26rem),
    radial-gradient(circle at top right, rgba(156, 198, 255, 0.08), transparent 32rem),
    linear-gradient(180deg, #0b1017 0%, var(--bg) 20rem);
  font: 16px/1.65 var(--body-font);
}

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

a:hover {
  color: #cbe1ff;
}

code,
pre,
input {
  font-family: var(--mono-font);
}

.shell {
  max-width: 1600px;
  margin: 0 auto;
  padding: 28px 26px 60px;
}

.masthead {
  position: sticky;
  top: 12px;
  z-index: 40;
  border-radius: 16px;
  border: 1px solid var(--line);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.035), transparent),
    color-mix(in srgb, var(--bg-panel) 92%, transparent);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
  padding: 18px 22px 14px;
  transition:
    padding 180ms ease,
    transform 180ms ease,
    background-color 180ms ease,
    border-color 180ms ease,
    box-shadow 180ms ease;
}

.masthead-row {
  display: flex;
  justify-content: space-between;
  gap: 18px 28px;
  align-items: flex-start;
}

.masthead-copy {
  min-width: 0;
  max-width: 52rem;
}

.masthead-actions {
  display: grid;
  justify-items: end;
  gap: 12px;
}

.eyebrow {
  margin: 0;
  color: var(--accent-2);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.source-link {
  color: var(--ink-dim);
  font-size: 0.82rem;
  white-space: nowrap;
}

.masthead h1 {
  margin: 8px 0 0;
  max-width: 22ch;
  font: 600 clamp(1.8rem, 3.2vw, 3.3rem)/0.94 var(--title-font);
  letter-spacing: -0.03em;
  transition: font-size 180ms ease, margin 180ms ease;
}

.subtitle {
  margin: 10px 0 0;
  max-width: 44rem;
  color: var(--ink);
  font-size: 1rem;
  transition: opacity 160ms ease, max-height 180ms ease, margin 180ms ease;
}

.hero-deck {
  max-width: 46rem;
  margin: 6px 0 0;
  color: var(--ink-soft);
  font-size: 0.95rem;
  transition: opacity 160ms ease, max-height 180ms ease, margin 180ms ease;
}

.meta-strip {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 10px;
  margin: 0;
  padding: 0;
}

.meta-strip div {
  min-width: 0;
  padding: 8px 10px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.025);
}

.meta-strip dt {
  margin: 0 0 2px;
  color: var(--ink-dim);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.meta-strip dd {
  margin: 0;
  font-size: 0.86rem;
}

.jump-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  transition: margin 180ms ease, padding 180ms ease;
}

.jump-links a {
  color: var(--ink-soft);
  padding: 7px 10px;
  border: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.02);
}

.jump-links a:hover {
  border-color: var(--line-strong);
  background: rgba(156, 198, 255, 0.08);
}

.masthead.is-collapsed {
  padding: 12px 18px 10px;
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.28);
}

.masthead.is-collapsed .masthead-row {
  align-items: center;
}

.masthead.is-collapsed .masthead-copy {
  max-width: 60rem;
}

.masthead.is-collapsed .eyebrow {
  margin-bottom: 2px;
  font-size: 0.68rem;
}

.masthead.is-collapsed h1 {
  margin-top: 2px;
  font-size: clamp(1.2rem, 2vw, 1.75rem);
  line-height: 1;
}

.masthead.is-collapsed .subtitle,
.masthead.is-collapsed .hero-deck {
  opacity: 0;
  max-height: 0;
  margin-top: 0;
  overflow: hidden;
  pointer-events: none;
}

.masthead.is-collapsed .masthead-actions {
  gap: 8px;
}

.masthead.is-collapsed .source-link {
  font-size: 0.76rem;
}

.masthead.is-collapsed .meta-strip div {
  padding: 6px 8px;
}

.masthead.is-collapsed .jump-links {
  margin-top: 10px;
  padding-top: 10px;
}

.masthead.is-collapsed .jump-links a {
  padding: 6px 9px;
  font-size: 0.84rem;
}

.layout {
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 26px;
  margin-top: 18px;
}

.toc {
  position: sticky;
  top: 18px;
  align-self: start;
  max-height: calc(100vh - 36px);
  overflow: auto;
  padding: 22px 18px 22px 20px;
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg-panel-2) 92%, transparent);
  backdrop-filter: blur(12px);
}

.toc-head {
  margin-bottom: 16px;
}

.toc-head p {
  margin: 0 0 12px;
  color: var(--ink-dim);
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.toc-head input {
  width: 100%;
  padding: 11px 12px;
  border: 1px solid var(--line);
  background: #0b1118;
  color: var(--ink);
  outline: none;
}

.toc-level {
  list-style: none;
  margin: 0;
  padding: 0;
}

.toc li {
  margin: 0;
}

.toc a {
  display: grid;
  grid-template-columns: 2.5rem 1fr;
  gap: 10px;
  align-items: start;
  padding: 8px 6px;
  color: var(--ink-soft);
}

.toc a[data-depth="2"] .toc-label {
  color: var(--section-color);
  font-weight: 700;
}

.toc a[data-depth="3"] {
  padding-left: 18px;
}

.toc a[data-depth="3"] .toc-label {
  color: var(--subsection-color);
  font-weight: 400;
}

.toc a[data-depth="4"] {
  padding-left: 32px;
}

.toc a[data-depth="4"] .toc-label {
  font-style: italic;
  color: var(--subsubsection-color);
}

.toc a.active {
  color: var(--ink);
  background: rgba(156, 198, 255, 0.08);
}

.toc a.active .toc-label {
  color: inherit;
}

.toc-number {
  color: var(--ink-dim);
  font-size: 0.76rem;
  letter-spacing: 0.12em;
}

.content {
  min-width: 0;
}

.contents-panel {
  padding: 24px 0 28px;
  border-top: 1px solid var(--line);
}

.contents-panel,
.chapter,
h2,
h3,
h4 {
  scroll-margin-top: 132px;
}

.section-bar {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 18px;
  color: var(--ink-dim);
  font-size: 0.76rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.contents-panel h2 {
  margin: 0 0 18px;
  font: 600 2rem/1.05 var(--title-font);
  letter-spacing: -0.02em;
}

.contents-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 28px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.contents-list li {
  border-top: 1px solid var(--line);
}

.contents-list a {
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 12px;
  padding: 14px 0;
  color: var(--ink-soft);
}

.contents-number {
  color: var(--ink-dim);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
}

.contents-text {
  display: grid;
  gap: 4px;
}

.contents-text strong {
  color: var(--ink);
  font-weight: 600;
}

.contents-text span {
  color: var(--ink-dim);
  font-size: 0.95rem;
}

.manual {
  border-top: 1px solid var(--line);
}

.chapter {
  padding: 28px 0 34px;
  border-bottom: 1px solid var(--line);
}

.chapter-head {
  margin-bottom: 18px;
}

.chapter-kicker {
  margin-bottom: 10px;
  color: var(--accent-2);
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h2,
h3,
h4 {
  margin: 0;
  font-weight: 600;
}

h2 {
  color: var(--section-color);
  font: 600 clamp(1.95rem, 2.5vw, 2.65rem)/1.05 var(--title-font);
  letter-spacing: -0.02em;
}

h3 {
  margin-top: 24px;
  color: var(--subsection-color);
  font-size: 1.18rem;
  font-weight: 400;
  letter-spacing: -0.01em;
}

h4 {
  margin-top: 20px;
  color: var(--subsubsection-color);
  font-size: 1rem;
  font-style: italic;
  font-weight: 400;
  letter-spacing: 0;
  text-transform: none;
}

.chapter-summary {
  max-width: 62rem;
  margin: 14px 0 0;
  color: var(--ink-soft);
  font-size: 1.02rem;
}

.sub-number {
  display: inline-block;
  margin-right: 10px;
  color: var(--ink-dim);
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  vertical-align: middle;
}

.anchor {
  display: inline-block;
  width: 1.4rem;
  margin-left: -1.4rem;
  color: transparent;
}

h2:hover .anchor,
h3:hover .anchor,
h4:hover .anchor {
  color: var(--ink-dim);
}

.related {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 12px;
  margin-top: 16px;
}

.related-label {
  color: var(--ink-dim);
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.related-link {
  color: var(--accent-3);
  font-size: 0.94rem;
}

p,
ul,
ol,
pre {
  max-width: 62rem;
}

p {
  margin: 14px 0 0;
  color: var(--ink-soft);
}

ul,
ol {
  margin: 14px 0 0;
  padding-left: 1.45rem;
}

li {
  margin: 7px 0;
  color: var(--ink-soft);
}

.inline-link {
  color: var(--accent-2);
  text-decoration: underline;
  text-decoration-color: rgba(126, 224, 194, 0.4);
  text-underline-offset: 0.18em;
}

code {
  padding: 0.16rem 0.32rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.07);
  color: #d9f1ff;
  font-size: 0.94em;
}

pre {
  overflow: auto;
  margin-top: 18px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  background: var(--bg-code);
  color: #d9e3ef;
}

pre code {
  padding: 0;
  border: 0;
  background: transparent;
}

@media (max-width: 1160px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .toc {
    position: static;
    max-height: none;
  }

  .contents-list {
    grid-template-columns: 1fr;
  }

  .masthead-row {
    flex-direction: column;
  }

  .masthead-actions {
    width: 100%;
    justify-items: start;
  }

  .meta-strip {
    justify-content: flex-start;
  }
}

@media (max-width: 720px) {
  .shell {
    padding: 16px 14px 40px;
  }

  .masthead {
    top: 8px;
    padding: 16px 14px 12px;
  }

  .masthead-row,
  .section-bar {
    flex-direction: column;
    align-items: flex-start;
  }

  .masthead h1 {
    max-width: none;
    font-size: clamp(1.6rem, 8vw, 2.25rem);
  }

  .meta-strip {
    justify-content: flex-start;
  }

  .toc a {
    grid-template-columns: 2.2rem 1fr;
  }

  .anchor {
    display: none;
  }

  .masthead.is-collapsed {
    padding: 12px 12px 10px;
  }

  .masthead.is-collapsed .jump-links {
    gap: 6px;
  }
}