@import url("https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght@9..144,500;9..144,700&family=Sora:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500&display=swap");

/* Dark theme matched to openfluke.com. Screen = dark; print/PDF overrides
   the variables back to a light, ink-friendly palette (see body.print-doc). */
:root {
  --ink: #e8eef4;
  --ink-soft: #93a8b8;
  --paper: #0a1016;
  --surface: #121a22;
  --surface-2: #18232e;
  --line: #2a3a48;
  --accent: #2ec4b6;
  --accent-deep: #1a9e92;
  --accent-light: #6fe0d4;
  --accent-soft: rgba(46, 196, 182, 0.14);
  --warn: #e6b45a;
  --warn-soft: rgba(230, 160, 70, 0.14);
  --ok: #4cd08a;
  --ok-soft: rgba(76, 208, 138, 0.15);
  --partial: #e6c85a;
  --partial-soft: rgba(230, 200, 90, 0.15);
  --missing: #ef8f8f;
  --missing-soft: rgba(230, 120, 120, 0.15);
  --code-bg: #060a0e;
  --code-ink: #d7e2ec;
  --code-inline-bg: #1a2732;
  --th-bg: #18232e;
  --ascii-bg: #0d151d;
  --panel-blur: rgba(10, 16, 22, 0.82);
  --shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
  --max: 52rem;
  --side: 16.5rem;
  --radius: 14px;
  --font-display: "Fraunces", Georgia, serif;
  --font-ui: "Sora", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  color-scheme: dark;
}

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(1100px 560px at 8% -12%, rgba(46, 196, 182, 0.14) 0%, transparent 55%),
    radial-gradient(900px 520px at 100% 0%, rgba(58, 90, 130, 0.2) 0%, transparent 50%),
    var(--paper);
  background-attachment: fixed;
  font-family: var(--font-ui);
  line-height: 1.65;
  font-size: 1.02rem;
}

a {
  color: var(--accent);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}

a:hover {
  color: var(--accent-light);
}

.skip {
  position: absolute;
  left: -999px;
  top: 0;
}
.skip:focus {
  left: 1rem;
  top: 1rem;
  z-index: 50;
  background: var(--surface);
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--line);
}

.shell {
  display: grid;
  grid-template-columns: var(--side) minmax(0, 1fr);
  min-height: 100vh;
}

.sidebar {
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  overflow: auto;
  padding: 1.25rem 1rem 2rem;
  border-right: 1px solid var(--line);
  background: var(--panel-blur);
  backdrop-filter: blur(10px);
}

.brand {
  display: block;
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.02em;
  margin-bottom: 0.2rem;
}

.brand-sub {
  font-size: 0.78rem;
  color: var(--ink-soft);
  margin-bottom: 1.25rem;
}

.nav-group {
  margin-bottom: 1rem;
}

.nav-group h2 {
  margin: 0 0 0.35rem;
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  font-weight: 600;
}

.nav-group a {
  display: block;
  padding: 0.28rem 0.45rem;
  margin: 0.08rem 0;
  border-radius: 8px;
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 0.84rem;
  line-height: 1.35;
}

.nav-group a:hover,
.nav-group a.active {
  background: var(--accent-soft);
  color: var(--accent);
}

.main {
  min-width: 0;
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  padding: 0.9rem 1.5rem;
  border-bottom: 1px solid var(--line);
  background: var(--panel-blur);
  backdrop-filter: blur(8px);
  position: sticky;
  top: 0;
  z-index: 5;
}

.topbar .meta {
  font-size: 0.82rem;
  color: var(--ink-soft);
}

.pager {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.pager a {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.4rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  text-decoration: none;
  color: var(--ink);
  font-size: 0.8rem;
}

.pager a:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.content {
  max-width: calc(var(--max) + 4rem);
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

.chapter-kicker {
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin: 0 0 0.5rem;
}

h1 {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 2.75rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 0 0 0.75rem;
  font-weight: 700;
}

h2 {
  font-family: var(--font-display);
  font-size: 1.45rem;
  margin: 2.2rem 0 0.75rem;
  letter-spacing: -0.015em;
}

h3 {
  font-size: 1.05rem;
  margin: 1.6rem 0 0.55rem;
  font-weight: 600;
}

p,
li {
  color: var(--ink);
}

.lede {
  font-size: 1.15rem;
  color: var(--ink-soft);
  margin: 0 0 1.5rem;
  max-width: 42rem;
}

.rule {
  height: 1px;
  background: var(--line);
  border: 0;
  margin: 1.5rem 0;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  box-shadow: var(--shadow);
}

.callout {
  border-left: 4px solid var(--accent);
  background: var(--accent-soft);
  padding: 0.9rem 1rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.25rem 0;
}

.callout.warn {
  border-left-color: var(--warn);
  background: var(--warn-soft);
}

.callout strong {
  display: block;
  margin-bottom: 0.2rem;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 1rem 0 1.5rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}

th,
td {
  text-align: left;
  padding: 0.55rem 0.7rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}

th {
  background: var(--th-bg);
  font-weight: 600;
  font-size: 0.8rem;
}

tr:last-child td {
  border-bottom: 0;
}

.status {
  display: inline-block;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  font-family: var(--font-mono);
}

.status.ok {
  background: var(--ok-soft);
  color: var(--ok);
}
.status.partial {
  background: var(--partial-soft);
  color: var(--partial);
}
.status.missing {
  background: var(--missing-soft);
  color: var(--missing);
}

.diagram {
  margin: 1.25rem 0 1.75rem;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: 0;
  overflow: visible;
  box-shadow: none;
}

.diagram pre,
pre.ascii {
  margin: 0;
  padding: 1rem 1.1rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.45;
  white-space: pre;
  background: var(--ascii-bg);
  color: var(--ink);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow-x: auto;
}

.diagram figcaption {
  margin-top: 0.75rem;
  font-size: 0.82rem;
  color: var(--ink-soft);
}

pre {
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.5;
  margin: 1rem 0 1.5rem;
}

pre:not(.ascii):not(.example-output) {
  background: var(--code-bg);
  color: var(--code-ink);
  border: 1px solid var(--line);
}

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--code-inline-bg);
  padding: 0.08em 0.35em;
  border-radius: 5px;
}

pre code {
  background: transparent;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.run-cmd {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin: 0.75rem 0 1rem;
  font-size: 0.88rem;
}

.run-cmd > span {
  color: var(--ink-soft);
  font-weight: 600;
  font-size: 0.82rem;
}

.run-cmd code {
  background: var(--code-bg);
  color: var(--code-ink);
  padding: 0.45rem 0.65rem;
  border-radius: 8px;
  font-size: 0.8rem;
}

.go-file-link {
  font-size: 0.88rem;
  font-weight: 600;
}

.example-output {
  background: #0f1a24;
  border: 1px solid #2a3a48;
  color: #c8e6d4;
  margin-top: 0.5rem;
}

.example-output code {
  background: transparent;
  color: inherit;
}

.example-output.fail {
  border-color: #6b3a3a;
  color: #f0c8c8;
}

.example-meta {
  font-size: 0.78rem;
  color: var(--ink-soft);
  margin: 0.35rem 0 0.5rem;
}

.examples {
  margin-top: 2.5rem;
  padding-top: 0.5rem;
  border-top: 2px solid var(--accent);
}

.examples > h2 {
  margin-top: 1rem;
  color: var(--accent);
}

.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.85rem;
}

.pill-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin: 0.75rem 0 1.25rem;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 0.28rem 0.65rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--surface);
  font-size: 0.78rem;
  color: var(--ink-soft);
}

/* Title page */
.title-page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 2rem 1.25rem;
  background:
    linear-gradient(160deg, rgba(46, 196, 182, 0.16), transparent 42%),
    linear-gradient(340deg, rgba(58, 90, 130, 0.18), transparent 38%),
    var(--paper);
}

.title-card {
  width: min(42rem, 100%);
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 22px;
  padding: clamp(2rem, 5vw, 3.25rem);
  box-shadow: var(--shadow);
  text-align: left;
}

.title-logo {
  display: block;
  width: min(11rem, 55%);
  height: auto;
  margin: 0 0 1.25rem;
}

.title-card .eyebrow {
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin: 0 0 1rem;
}

.title-card h1 {
  font-size: clamp(2.6rem, 8vw, 4.2rem);
  margin: 0 0 0.4rem;
}

.title-card .subtitle {
  font-size: 1.2rem;
  color: var(--ink-soft);
  margin: 0 0 1.5rem;
  max-width: 28rem;
}

.title-meta {
  display: grid;
  gap: 0.35rem;
  font-size: 0.92rem;
  color: var(--ink-soft);
  margin-bottom: 1.75rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.7rem 1.1rem;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.92rem;
}

.btn-primary {
  background: var(--accent);
  color: #041014;
}

.btn-primary:hover {
  background: var(--accent-light);
  color: #041014;
}

.btn-ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--ink);
}

.btn-ghost:hover {
  border-color: var(--accent);
  color: var(--accent);
}

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

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

.toc-list a {
  display: grid;
  grid-template-columns: 3.2rem 1fr;
  gap: 0.75rem;
  padding: 0.85rem 0.2rem;
  text-decoration: none;
  color: inherit;
}

.toc-list a:hover {
  background: var(--accent-soft);
}

.toc-list .num {
  font-family: var(--font-mono);
  color: var(--accent);
  font-weight: 500;
}

.toc-list .title {
  font-weight: 600;
}

.toc-list .blurb {
  grid-column: 2;
  font-size: 0.88rem;
  color: var(--ink-soft);
  margin-top: 0.15rem;
}

.part {
  margin: 2rem 0 0.75rem;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 700;
}

.menu-btn {
  display: none;
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  border-radius: 10px;
  padding: 0.4rem 0.7rem;
  font: inherit;
  cursor: pointer;
}

@media (max-width: 980px) {
  .shell {
    grid-template-columns: 1fr;
  }
  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    width: min(86vw, 18rem);
    transform: translateX(-105%);
    transition: transform 0.2s ease;
    z-index: 20;
    box-shadow: var(--shadow);
    background: var(--paper);
  }
  body.nav-open .sidebar {
    transform: translateX(0);
  }
  body.nav-open::after {
    content: "";
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.55);
    z-index: 15;
  }
  .menu-btn {
    display: inline-flex;
  }
  .grid-2 {
    grid-template-columns: 1fr;
  }
}

/* ---------------------------------------------------------------------------
   Polish: focus states, custom scrollbars, tactile hovers, accent details.
--------------------------------------------------------------------------- */
::selection {
  background: rgba(46, 196, 182, 0.3);
  color: #eaf6f4;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

html {
  scrollbar-color: #2a3a48 transparent;
  scrollbar-width: thin;
}
::-webkit-scrollbar {
  width: 11px;
  height: 11px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: #24313d;
  border: 2px solid var(--paper);
  border-radius: 999px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--accent-deep);
}

.title-card {
  position: relative;
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.title-card::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), #a78bfa 55%, transparent);
}
.title-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 26px 70px rgba(0, 0, 0, 0.55);
}

.btn-primary {
  box-shadow: 0 8px 24px rgba(46, 196, 182, 0.28);
  transition: transform 0.15s ease, box-shadow 0.2s ease, background 0.15s ease;
}
.btn-primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 12px 30px rgba(46, 196, 182, 0.4);
}
.btn-ghost {
  transition: border-color 0.15s ease, color 0.15s ease, background 0.15s ease;
}
.btn-ghost:hover {
  background: var(--accent-soft);
}

.nav-group a {
  border-left: 2px solid transparent;
  transition: background 0.12s ease, color 0.12s ease, border-color 0.12s ease;
}
.nav-group a:hover,
.nav-group a.active {
  border-left-color: var(--accent);
}

.pager a {
  transition: transform 0.15s ease, border-color 0.15s ease, color 0.15s ease;
}
.pager a:hover {
  transform: translateY(-1px);
}

.card {
  transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}
.card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
}

.status {
  border: 1px solid currentColor;
  line-height: 1.4;
}

.chapter-kicker {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
}
.chapter-kicker::before {
  content: "";
  width: 1.6rem;
  height: 2px;
  background: var(--accent);
  display: inline-block;
}

pre:not(.ascii):not(.example-output) {
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04), var(--shadow);
}

.toc-list a {
  border-radius: 8px;
  transition: background 0.12s ease, padding-left 0.12s ease;
}
.toc-list a:hover {
  padding-left: 0.6rem;
}

/* Title / landing page extras */
.title-page {
  padding: 1.5rem 1.25rem;
}

/* Two-column landing so it fits the viewport without scrolling.
   Scoped to .landing so the PDF print cover (.title-card, no .landing)
   keeps its single-column layout. */
.title-card.landing {
  width: min(62rem, 100%);
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(1.5rem, 4vw, 3rem);
  align-items: center;
  padding: clamp(1.6rem, 3.5vw, 2.6rem);
}
.title-card.landing .title-logo {
  width: min(8.5rem, 42%);
  margin-bottom: 0.9rem;
}
.title-card.landing h1 {
  font-size: clamp(2.4rem, 5vw, 3.4rem);
  margin-bottom: 0.35rem;
}
.title-card.landing .subtitle {
  font-size: 1.05rem;
  margin-bottom: 1.15rem;
}
.tc-side > * + * {
  margin-top: 1.15rem;
}
.tc-side .title-stats,
.tc-side .title-meta,
.tc-side .title-parts {
  margin: 0;
}

@media (max-width: 820px) {
  .title-card.landing {
    grid-template-columns: 1fr;
    align-items: start;
  }
}

.title-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.3rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface-2);
  font-size: 0.7rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-soft);
  font-weight: 600;
  margin: 0 0 1.1rem;
}
.title-badge .dot {
  width: 7px;
  height: 7px;
  border-radius: 999px;
  background: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.grad {
  background: linear-gradient(90deg, var(--accent), #a78bfa);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.title-stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.65rem;
  margin: 0.5rem 0 1.5rem;
}
.stat {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.75rem 0.4rem;
  background: var(--surface-2);
  text-align: center;
}
.stat-num {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
}
.stat-label {
  font-size: 0.68rem;
  color: var(--ink-soft);
  margin-top: 0.3rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.title-parts {
  margin: 0 0 1.75rem;
}
.title-parts .label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
  font-weight: 600;
  margin: 0 0 0.55rem;
}
a.pill {
  text-decoration: none;
  transition: border-color 0.12s ease, color 0.12s ease, background 0.12s ease, transform 0.12s ease;
}
a.pill:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-soft);
  transform: translateY(-1px);
}

@media (max-width: 560px) {
  .title-stats {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none !important;
    scroll-behavior: auto !important;
  }
}

/* ---------------------------------------------------------------------------
   Print / PDF: reset the palette to a light, ink-friendly theme. The PDF is
   generated from print.html (body.print-doc); a normal chapter printed with
   Ctrl+P is caught by @media print.
--------------------------------------------------------------------------- */
body.print-doc {
  --ink: #14202b;
  --ink-soft: #3a4a58;
  --paper: #ffffff;
  --surface: #ffffff;
  --surface-2: #eef3f6;
  --line: #d5dee6;
  --accent: #0b6e6a;
  --accent-deep: #085450;
  --accent-light: #0b6e6a;
  --accent-soft: #d7efed;
  --warn: #9a5b12;
  --warn-soft: #f6ead7;
  --ok: #1f6b3a;
  --ok-soft: #dff0e5;
  --partial: #7a5a10;
  --partial-soft: #f3e8c8;
  --missing: #6b3a3a;
  --missing-soft: #f3e0e0;
  --code-bg: #12202c;
  --code-ink: #e8eef4;
  --code-inline-bg: #e7eef2;
  --th-bg: #eef3f6;
  --ascii-bg: #eef3f7;
  --shadow: 0 12px 40px rgba(20, 32, 43, 0.08);
  background: #ffffff;
  color: var(--ink);
}

body.print-doc .grad {
  background: none;
  -webkit-text-fill-color: currentColor;
  color: var(--ink);
}

@media print {
  html {
    color-scheme: light;
  }
  .grad {
    background: none;
    -webkit-text-fill-color: currentColor;
    color: var(--ink);
  }
  body {
    --ink: #14202b;
    --ink-soft: #3a4a58;
    --paper: #ffffff;
    --surface: #ffffff;
    --surface-2: #eef3f6;
    --line: #d5dee6;
    --accent: #0b6e6a;
    --accent-light: #0b6e6a;
    --accent-soft: #d7efed;
    --code-bg: #12202c;
    --code-ink: #e8eef4;
    --code-inline-bg: #e7eef2;
    --th-bg: #eef3f6;
    --ascii-bg: #eef3f7;
    background: #ffffff !important;
  }
  .sidebar,
  .topbar,
  .menu-btn {
    display: none !important;
  }
  .shell {
    display: block;
  }
}