:root {
  /* — Ground & panels (dark graphite drafting sheet, just a hint of blue) — */
  --ground:      #14191F;   /* sheet / page field */
  --panel:       #1C232B;   /* raised card / inset drawing */
  --panel-2:     #10141A;   /* deeper inset */

  /* — Draughting inks — */
  --ink:         #F5F1E4;   /* PRIMARY text — warm drafting cream */
  --ink-soft:    #C2BDA8;   /* muted / caption / annotation — warm stone */
  --cyan:        #7FCDEA;   /* linework highlight, links, ornament */
  --cyan-bright: #B4E4F7;   /* focus ring */
  --redline:     #E8674F;   /* rare accent: active nav, redline callout */
  --amber:       #F0C987;   /* warm accent: buttons, marks, doodles */
  --amber-bright:#F7DCA9;   /* warm hover */

  /* — Rules & grid (kept faint on purpose) — */
  --line:        rgba(240,233,214,0.42);  /* cream hairline sheet border */
  --line-soft:   rgba(240,233,214,0.16);  /* inner double-rule */
  --grid-major:  rgba(226,218,196,0.11);  /* graph-paper major lines */
  --grid-minor:  rgba(226,218,196,0.05);  /* graph-paper minor lines */

  /* — Type — */
  --font-display: "Chakra Petch", "Bahnschrift", "DIN Alternate", system-ui, sans-serif;
  --font-body:    "Rajdhani", "Chakra Petch", system-ui, sans-serif;
  --font-mono:    "Share Tech Mono", ui-monospace, "Cascadia Code", Consolas, monospace;

  /* — Metrics — */
  --maxw:        1080px;
  --frame-inset: clamp(0.75rem, 2.4vw, 2rem);  /* sheet distance from viewport edge */
  --pad-x:       clamp(1.1rem, 4vw, 2.6rem);   /* content inner padding */
  --focus:       var(--cyan-bright);
}

/* ======================================================================
   RESET / BASE
   ====================================================================== */
*, *::before, *::after { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

html, body { margin: 0; padding: 0; }

body {
  min-height: 100vh;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 1.02rem;
  line-height: 1.6;
  background-color: var(--ground);
  /* A drafting sheet: graph-paper grid (CSS) beneath faint technical
     linework — gears, a protractor, an orthographic plan (assets/blueprint.svg). */
  background-image:
    url('assets/blueprint.svg'),
    repeating-linear-gradient(0deg,  var(--grid-major) 0, var(--grid-major) 1px, transparent 1px, transparent 130px),
    repeating-linear-gradient(90deg, var(--grid-major) 0, var(--grid-major) 1px, transparent 1px, transparent 130px),
    repeating-linear-gradient(0deg,  var(--grid-minor) 0, var(--grid-minor) 1px, transparent 1px, transparent 26px),
    repeating-linear-gradient(90deg, var(--grid-minor) 0, var(--grid-minor) 1px, transparent 1px, transparent 26px);
  background-attachment: fixed;
  /* svg pinned left-bottom and scaled to viewport HEIGHT (auto 100%), the
     same rule the moving machinery layer uses — so the linework and the
     gears line up unit-for-unit at every window size and never drift over
     each other. On wide screens the sheet's right side is plain grid. */
  background-position: left bottom, center, center, center, center;
  background-repeat: no-repeat, repeat, repeat, repeat, repeat;
  background-size: auto 100%, auto, auto, auto, auto;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; }

a {
  color: var(--cyan);
  text-decoration: none;
  transition: color 0.18s ease;
}
a:hover { color: var(--amber-bright); text-decoration: underline; text-underline-offset: 3px; }

::selection { background: rgba(240, 201, 135, 0.28); }

/* Global visible focus — never removed */
:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
  border-radius: 2px;
}

/* ======================================================================
   SHEET FRAME (.plate) — the constant "drawing sheet" identity
   ====================================================================== */
.plate {
  position: relative;
  min-height: 100vh;
  margin: var(--frame-inset);
  border: 1px solid var(--line);
  display: flex;
  flex-direction: column;
}

/* inner double rule */
.plate::before {
  content: "";
  position: absolute;
  inset: 6px;
  border: 1px solid var(--line-soft);
  pointer-events: none;
  z-index: 0;
}

/* dimension ticks along top & bottom inner margins */
.plate::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  top: 12px;
  bottom: 12px;
  pointer-events: none;
  z-index: 0;
  background-image:
    repeating-linear-gradient(90deg, var(--line) 0, var(--line) 1px, transparent 1px, transparent 28px),
    repeating-linear-gradient(90deg, var(--line) 0, var(--line) 1px, transparent 1px, transparent 28px);
  background-repeat: no-repeat, no-repeat;
  background-position: top left, bottom left;
  background-size: 100% 6px, 100% 6px;
}

/* numbers read off the top scale (built by assets/scale.js) */
.plate-scale {
  position: absolute;
  left: 16px;
  right: 16px;
  top: 19px;
  height: 10px;
  pointer-events: none;
  z-index: 0;
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.04em;
  color: var(--line);
}
.plate-scale span {
  position: absolute;
  top: 0;
  transform: translateX(-50%);
  opacity: 0.7;
}

/* keep real content above the frame pseudo-layers */
.masthead, main, .titleblock { position: relative; z-index: 2; }

/* scroll-driven meshing gears — a fixed layer behind the sheet content,
   above the graph-paper ground (built by assets/scroll-gears.js) */
.gear-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  overflow: hidden;
}
.gear-bg svg { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }

/* ======================================================================
   NAV (.masthead / .chart-nav / .seal / .seal-mark / .nav-links / .active)
   ====================================================================== */
.masthead {
  border-bottom: 1px solid var(--line-soft);
}

.chart-nav {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0.9rem var(--pad-x);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.seal {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: 0.16em;
  font-size: 1.05rem;
  color: var(--ink);
}
.seal:hover { color: var(--ink); text-decoration: none; opacity: 0.9; }

.seal-mark {
  width: 30px;
  height: 30px;
  display: block;
  color: var(--amber);
  animation: seal-spin 42s linear infinite;  /* the little gear idles along */
}
@keyframes seal-spin { to { transform: rotate(360deg); } }

.nav-links {
  display: flex;
  align-items: center;
  gap: clamp(0.15rem, 1.2vw, 0.6rem);
  list-style: none;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}
.nav-links a {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
  padding: 0.55rem 0.7rem;
}
.nav-links a:hover { color: var(--ink); text-decoration: none; }

.nav-links a.active {
  color: var(--redline);
  position: relative;
}
.nav-links a.active::after {
  content: "";
  position: absolute;
  left: 0.7rem;
  right: 0.7rem;
  bottom: 0.32rem;
  height: 2px;
  background: var(--amber);
}

/* cross-link to the star-chart edition */
.nav-links a.alt-edition { color: var(--cyan); }
.nav-links a.alt-edition:hover { color: var(--amber-bright); }

/* ======================================================================
   LAYOUT / MAIN
   ====================================================================== */
main {
  flex: 1 0 auto;
  max-width: var(--maxw);
  width: 100%;
  margin: 0 auto;
  padding: clamp(2.5rem, 6vw, 4.5rem) var(--pad-x) clamp(3rem, 8vw, 5rem);
}

/* ======================================================================
   TYPOGRAPHY
   ====================================================================== */
.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 0 0 1.1rem;
}
.eyebrow::before {
  content: "\25B8\00A0";  /* ▸ + nbsp */
  color: var(--amber);
}

.plate-title {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(2.4rem, 6.4vw, 4rem);
  line-height: 1.04;
  letter-spacing: 0.005em;
  color: var(--ink);
  margin: 0 0 1.1rem;
}

h2 {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  color: var(--ink);
  margin: 2.75rem 0 0.6rem;
}
h2::before {
  content: "// ";
  color: var(--amber);
}

p {
  font-family: var(--font-body);
  font-size: clamp(1.08rem, 1.4vw, 1.24rem);
  line-height: 1.62;
  color: var(--ink);
  max-width: 70ch;
  margin: 0 0 1rem;
}

.lede {
  font-family: var(--font-body);
  font-weight: 500;
  color: var(--ink);
  opacity: 0.94;
  max-width: 66ch;
  margin: 0 0 1.25rem;
}

/* Text-only pages let the prose fill the full sheet width. */
.hero:not(:has(.draw)) p,
.hero:not(:has(.draw)) .lede {
  max-width: none;
}

.readout {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
  max-width: none;
  margin: 0 0 1rem;
}

/* ======================================================================
   HERO
   ====================================================================== */
.hero { animation: rise 0.5s ease both; }

/* Home: two-column grid (text + drawing). */
.hero:has(.draw),
.hero.hero--home {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  gap: clamp(1.5rem, 5vw, 3.5rem);
  align-items: center;
}

/* staggered entry for direct children */
.hero > * { animation: rise 0.5s ease both; }
.hero > *:nth-child(1) { animation-delay: 0.00s; }
.hero > *:nth-child(2) { animation-delay: 0.06s; }
.hero > *:nth-child(3) { animation-delay: 0.12s; }
.hero > *:nth-child(4) { animation-delay: 0.18s; }
.hero > *:nth-child(5) { animation-delay: 0.24s; }

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-top: 1.4rem;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: none; }
}

/* ======================================================================
   BUTTONS (.chart-btn / .chart-btn--ghost)
   ====================================================================== */
.chart-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.15rem;
  border: 1px solid var(--amber);
  border-radius: 6px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  color: var(--amber);
  background: transparent;
  transition: background-color 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
.chart-btn span { transition: transform 0.18s ease; display: inline-block; }
.chart-btn:hover,
.chart-btn:focus-visible {
  background: var(--amber-bright);
  color: var(--ground);
  border-color: var(--amber-bright);
  text-decoration: none;
}
.chart-btn:hover span,
.chart-btn:focus-visible span { transform: translateX(3px); }

.chart-btn--ghost {
  border-color: transparent;
  background: transparent;
  color: var(--ink-soft);
  padding-left: 0.4rem;
  padding-right: 0.4rem;
}
.chart-btn--ghost:hover,
.chart-btn--ghost:focus-visible {
  background: transparent;
  color: var(--amber-bright);
  border-color: transparent;
}

/* ======================================================================
   SIGNATURE — THE BLACKBIRD PLAN (.draw / .draw-svg + drawing primitives)
   ====================================================================== */
.draw {
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: 8px;
  padding: 0.85rem;
  width: 100%;
  max-width: 420px;
  margin: 0 auto;
  position: relative;
  /* inset drawing grid */
  background-image:
    repeating-linear-gradient(90deg, transparent 0, transparent 31px, var(--grid-minor) 31px, var(--grid-minor) 32px),
    repeating-linear-gradient(0deg,  transparent 0, transparent 31px, var(--grid-minor) 31px, var(--grid-minor) 32px);
}

.draw-svg {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 420 / 500;
  overflow: visible;
}

/* aircraft outline — drawn in like ink from a plotter */
.draw-outline {
  fill: rgba(127,205,234,0.05);
  stroke: var(--cyan);
  stroke-width: 1.6;
  stroke-linejoin: round;
  stroke-linecap: round;
  stroke-dasharray: 2400;
  stroke-dashoffset: 2400;
  animation: draw-in 1.4s ease forwards;
}
.draw-line {
  fill: none;
  stroke: var(--ink);
  stroke-width: 1;
  stroke-linecap: round;
  stroke-linejoin: round;
  opacity: 0.8;
}
.draw-fill { fill: rgba(234,242,248,0.10); stroke: var(--ink); stroke-width: 0.8; }

/* dashed centre / construction lines */
.draw-center {
  fill: none;
  stroke: var(--cyan);
  stroke-width: 0.8;
  stroke-dasharray: 10 4 2 4;
  opacity: 0.55;
}

/* dimension lines (thin, with arrowheads via markers) + witness lines */
.draw-dim {
  fill: none;
  stroke: var(--ink-soft);
  stroke-width: 0.8;
  marker-start: url(#arrow);
  marker-end: url(#arrow);
}
.draw-witness { fill: none; stroke: var(--ink-soft); stroke-width: 0.6; opacity: 0.7; }
.draw-dim-label {
  font-family: var(--font-mono);
  font-size: 11px;
  fill: var(--ink-soft);
  letter-spacing: 0.04em;
}

/* leader callouts: circled numbers */
.draw-leader { fill: none; stroke: var(--cyan); stroke-width: 0.8; opacity: 0.8; }
.draw-tag circle { fill: var(--panel-2); stroke: var(--cyan); stroke-width: 1; }
.draw-tag text {
  font-family: var(--font-mono);
  font-size: 11px;
  fill: var(--cyan);
  text-anchor: middle;
  dominant-baseline: central;
}

/* Instrument telemetry panel BELOW the drawing */
.draw-times {
  display: flex;
  justify-content: space-between;
  gap: 0.6rem;
  width: 100%;
  max-width: 420px;
  margin: 0.8rem auto 0;
  padding: 0 0.15rem;
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.draw-times span { display: flex; flex-direction: column; gap: 0.22rem; }
.draw-times b {
  color: var(--ink);
  font-weight: 400;
  font-size: 0.74rem;
  letter-spacing: 0.05em;
}

@keyframes draw-in { to { stroke-dashoffset: 0; } }

/* ======================================================================
   CATALOGUE (random stuff) — .catalogue / .catalogue-grid / .part-card
   ====================================================================== */
.catalogue { margin-top: clamp(2rem, 5vw, 3rem); }

.catalogue-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1rem;
}

.part-card {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: 8px;
  padding: 1.25rem 1.3rem 1.4rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
  transition: border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}
/* corner tick marks echoing the sheet frame */
.part-card::before,
.part-card::after {
  content: "";
  position: absolute;
  width: 8px;
  height: 8px;
  pointer-events: none;
}
.part-card::before {
  top: 7px; left: 7px;
  border-top: 1px solid var(--cyan);
  border-left: 1px solid var(--cyan);
}
.part-card::after {
  bottom: 7px; right: 7px;
  border-bottom: 1px solid var(--cyan);
  border-right: 1px solid var(--cyan);
}
.part-card:hover {
  border-color: var(--cyan);
  transform: translateY(-3px);
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.45);
}
.part-card:hover::before,
.part-card:hover::after { border-color: var(--amber); }

.part-card header {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.part-glyph { width: 30px; height: 30px; flex-shrink: 0; color: var(--ink-soft); }
.part-glyph * { transition: stroke 0.18s ease, fill 0.18s ease; }
.part-glyph [fill="none"], .part-glyph line, .part-glyph circle, .part-glyph path, .part-glyph polyline {
  vector-effect: non-scaling-stroke;
}
.part-card:hover .part-glyph { color: var(--cyan-bright); }

.part-desig {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--cyan);
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

.part-card h3 {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--ink);
  margin: 0;
}

.part-card p {
  font-family: var(--font-body);
  font-size: 1.02rem;
  color: var(--ink-soft);
  max-width: none;
  margin: 0;
  flex: 1;
}

.part-spec {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--ink-soft);
}

.enter {
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
  margin-top: 0.15rem;
}
.enter:hover { color: var(--amber-bright); text-decoration: none; }
.enter span { display: inline-block; transition: transform 0.18s ease; }
.enter:hover span,
.enter:focus-visible span { transform: translateX(3px); }

/* ======================================================================
   RESUME — .status-plate / .gearset / .status-light
   ====================================================================== */
.status-plate {
  margin-top: 2.25rem;
  background: var(--panel);
  border: 1px solid var(--line-soft);
  border-radius: 8px;
  padding: 2rem 1.8rem;
  max-width: 44ch;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  text-align: center;
}

.gearset { width: 150px; height: 120px; color: var(--cyan); }
.gearset .gear { transform-box: fill-box; transform-origin: center; }
.gearset .gear-a { animation: spin 24s linear infinite; }
/* meshed gear turns the opposite way, slightly faster (smaller) */
.gearset .gear-b { animation: spin-rev 16s linear infinite; }

@keyframes spin      { from { transform: rotate(0deg);   } to { transform: rotate(360deg);  } }
@keyframes spin-rev  { from { transform: rotate(0deg);   } to { transform: rotate(-360deg); } }

.status-plate .readout { margin: 0; }
.status-plate .readout.sub { color: var(--ink-soft); }

.status-light {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--cyan);
  box-shadow: 0 0 8px var(--cyan);
  margin-right: 0.4rem;
  vertical-align: baseline;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse { 0%, 100% { opacity: 1; } 50% { opacity: 0.3; } }

/* ======================================================================
   TITLE BLOCK (.titleblock) — engineering-drawing footer
   ====================================================================== */
.titleblock {
  flex-shrink: 0;
  max-width: var(--maxw);
  width: 100%;
  margin: 0 auto;
  padding: 0 var(--pad-x) 2.5rem;
}
.titleblock-grid {
  display: flex;
  flex-wrap: wrap;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
}
.tb-cell {
  flex: 1 1 auto;
  min-width: 92px;
  padding: 0.5rem 0.8rem;
  border-right: 1px solid var(--line-soft);
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}
.tb-cell:last-child { border-right: none; }
.tb-cell.tb-title { flex: 2 1 200px; }
.tb-key {
  font-size: 0.58rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-soft);
}
.tb-val {
  font-size: 0.86rem;
  letter-spacing: 0.06em;
  color: var(--ink);
}
.tb-val.accent { color: var(--cyan); }

/* ======================================================================
   RESPONSIVE
   ====================================================================== */
@media (max-width: 760px) {
  .hero:has(.draw),
  .hero.hero--home { grid-template-columns: 1fr; }
  .hero:has(.draw) .draw,
  .hero.hero--home .draw { max-width: 360px; margin-top: 0.5rem; }
}

@media (max-width: 560px) {
  .chart-nav { justify-content: center; text-align: center; }
  .nav-links { justify-content: center; }
  .catalogue-grid { grid-template-columns: 1fr; }
  .tb-cell { flex-basis: 40%; }
}

/* ======================================================================
   REDUCED MOTION
   ====================================================================== */
@media (prefers-reduced-motion: reduce) {
  .hero,
  .hero > *,
  .status-light,
  .seal-mark,
  .gearset .gear { animation: none; }
  .draw-outline { stroke-dashoffset: 0; animation: none; }
}