/* ==========================================================================
   tessera.noizu.com — design system
   Dark editorial, tile/mosaic motif, mono as a first-class face.
   Layers: tokens → base → header/footer → hero + W1 inspector → seam →
   morph (W2) → pillars → code figures → hostlab (W3) → picker (W4) →
   status (W5) → quickstart → faq → contribute → motion rules.
   ========================================================================== */

/* ---- tokens -------------------------------------------------------------- */

:root {
  /* ink & paper */
  --bg: #0d0c10;
  --bg-raised: #141317;
  --bg-panel: #100f13;
  --bg-sunken: #0a090c;
  --ink: #f2f0eb;
  --ink-soft: #cfcac0;
  --muted: #9a978f;
  --faint: #6d6a63;

  /* seams & lines */
  --line: #2a2830;
  --line-strong: #3a3844;

  /* palette: terracotta / ochre / teal / workhorse blue */
  --accent: #ff7a45;
  --accent-deep: #e05a28;
  --ochre: #ffc24b;
  --teal: #37d5b3;
  --blue: #7aa2ff;
  --amber: #ffb84b;
  --red: #ff6b5e;

  /* type */
  --font-body: "Inter Tight", system-ui, -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "SF Mono", monospace;

  --step--1: clamp(0.78rem, 0.74rem + 0.2vw, 0.85rem);
  --step-0: clamp(0.95rem, 0.9rem + 0.3vw, 1.05rem);
  --step-1: clamp(1.15rem, 1.05rem + 0.5vw, 1.35rem);
  --step-2: clamp(1.45rem, 1.2rem + 1.2vw, 2rem);
  --step-3: clamp(1.9rem, 1.4rem + 2.5vw, 3rem);
  --step-4: clamp(2.4rem, 1.5rem + 4.5vw, 4.2rem);

  --measure: 66ch;
  --container: 1160px;
  --radius: 14px;
  --radius-sm: 8px;
}

/* ---- base ---------------------------------------------------------------- */

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 84px;
}

body {
  margin: 0;
  background:
    radial-gradient(1100px 500px at 85% -8%, rgba(255, 122, 69, 0.07), transparent 60%),
    radial-gradient(900px 420px at 8% 12%, rgba(122, 162, 255, 0.05), transparent 55%),
    var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* faint tesserae field behind everything */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 84px 84px;
  opacity: 0.16;
  pointer-events: none;
  mask-image: radial-gradient(1200px 700px at 50% 0%, #000 0%, transparent 75%);
  -webkit-mask-image: radial-gradient(1200px 700px at 50% 0%, #000 0%, transparent 75%);
}

img, svg { display: block; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

code, .mono, pre {
  font-family: var(--font-mono);
  font-feature-settings: "ss02" on;
}

code {
  font-size: 0.88em;
  background: var(--bg-sunken);
  border: 1px solid var(--line);
  border-radius: 5px;
  padding: 0.08em 0.38em;
  color: var(--ochre);
  white-space: nowrap;
}

pre code { border: 0; padding: 0; background: none; color: inherit; white-space: pre; }

.container {
  width: min(var(--container), calc(100% - 3rem));
  margin-inline: auto;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: #16090474;
  color: #1a0c05;
  padding: 0.5rem 1rem;
  border-radius: 0 0 var(--radius-sm) 0;
  z-index: 100;
}
.skip-link:focus { left: 0; }

/* ---- header / footer ------------------------------------------------------ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: color-mix(in srgb, var(--bg) 78%, transparent);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.65rem 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  color: var(--ink);
}
.brand:hover { text-decoration: none; }

.brand-mark { flex: none; }
.tile-a { fill: var(--accent); }
.tile-b { fill: var(--ochre); }
.tile-c { fill: var(--teal); }
.tile-d { fill: var(--line-strong); }

.brand-name {
  font-weight: 700;
  font-size: 1.06rem;
  letter-spacing: -0.01em;
}

.brand-tag {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--faint);
  border: 1px solid var(--line);
  border-radius: 99px;
  padding: 0.1rem 0.55rem;
  margin-top: 0.1rem;
}

.site-nav {
  display: flex;
  gap: 1.15rem;
  font-size: var(--step--1);
  color: var(--muted);
  flex-wrap: wrap;
  justify-content: flex-end;
}
.site-nav a { color: var(--muted); }
.site-nav a:hover { color: var(--ink); text-decoration: none; border-bottom: 2px solid var(--accent); }

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-sunken);
  margin-top: 6rem;
}

.footer-inner {
  padding: 3rem 0 2.4rem;
  display: grid;
  grid-template-columns: minmax(260px, 1.2fr) minmax(300px, 1fr);
  gap: 2.5rem;
}

.footer-title {
  margin: 0 0 0.5rem;
  font-size: var(--step-1);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.footer-line { margin: 0; color: var(--muted); max-width: 38ch; }

.footer-nav {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 0.45rem 1.5rem;
  font-size: var(--step--1);
  align-content: center;
}
.footer-nav a { color: var(--ink-soft); }

.footer-legal, .footer-org {
  grid-column: 1 / -1;
  margin: 0;
  font-size: var(--step--1);
  color: var(--faint);
}
.footer-org { border-top: 1px dashed var(--line); padding-top: 1.1rem; }

/* ---- section scaffolding -------------------------------------------------- */

.section { padding: 4.5rem 0 1rem; position: relative; }

.section h2 {
  font-size: var(--step-3);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.12;
  margin: 0 0 1rem;
  max-width: 22ch;
}

.section-lede {
  font-size: var(--step-1);
  line-height: 1.55;
  color: var(--ink-soft);
  max-width: 62ch;
  margin: 0 0 1.6rem;
}

.body-text {
  color: var(--ink-soft);
  max-width: var(--measure);
  margin: 1.1rem 0;
}

/* section marker: a small tile row divider */
.section::before {
  content: "";
  display: block;
  width: 76px;
  height: 6px;
  margin-bottom: 2.2rem;
  background-image:
    linear-gradient(90deg, var(--accent) 0 18px, transparent 18px 19px),
    linear-gradient(90deg, var(--ochre) 0 18px, transparent 18px 19px),
    linear-gradient(90deg, var(--teal) 0 18px, transparent 18px 19px),
    linear-gradient(90deg, var(--line-strong) 0 18px, transparent 18px 19px);
  background-size: 19px 6px;
  background-repeat: repeat-x;
}

/* ---- buttons ---------------------------------------------------------------- */

.cta-row {
  display: flex;
  gap: 0.9rem;
  flex-wrap: wrap;
  margin: 1.8rem 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.68rem 1.35rem;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }

.btn-accent {
  background: var(--accent);
  color: #1a0c05;
}
.btn-accent:hover { background: var(--accent-deep); }

.btn-outline {
  border-color: var(--line-strong);
  color: var(--ink);
  background: transparent;
}
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }

.btn-ghost {
  background: transparent;
  color: var(--muted);
  border-color: var(--line);
  font-weight: 500;
}
.btn-ghost:hover { color: var(--ink); border-color: var(--line-strong); }

.btn-sm { padding: 0.4rem 0.9rem; font-size: var(--step--1); }

/* segmented control */
.seg {
  display: inline-flex;
  border: 1px solid var(--line-strong);
  border-radius: 10px;
  overflow: hidden;
  background: var(--bg-sunken);
}

.seg-btn {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 0.42rem 0.95rem;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}
.seg-btn + .seg-btn { border-left: 1px solid var(--line); }
.seg-btn:hover { color: var(--ink); }
.seg-btn[aria-selected="true"], .seg-btn[data-active="true"], .seg-btn.on {
  background: var(--line-strong);
  color: var(--ochre);
}

/* ---- hero ------------------------------------------------------------------- */

.hero {
  position: relative;
  overflow: clip;
  padding: 6.5rem 0 3rem;
  min-height: 88svh;
  display: flex;
  align-items: flex-start;
}

/* three parallax mosaic fields */
.mosaic {
  position: absolute;
  inset: -20% -10%;
  z-index: -1;
  pointer-events: none;
  will-change: transform;
}

.mosaic-far {
  background-image:
    linear-gradient(var(--line) 2px, transparent 2px),
    linear-gradient(90deg, var(--line) 2px, transparent 2px);
  background-size: 120px 120px;
  opacity: 0.5;
  mask-image: radial-gradient(900px 620px at 70% 30%, #000 0%, transparent 70%);
  -webkit-mask-image: radial-gradient(900px 620px at 70% 30%, #000 0%, transparent 70%);
}

.mosaic-mid {
  background-image: radial-gradient(circle at center, var(--line-strong) 0 5px, transparent 6px);
  background-size: 64px 64px;
  opacity: 0.6;
  mask-image: radial-gradient(720px 480px at 18% 60%, #000 0%, transparent 70%);
  -webkit-mask-image: radial-gradient(720px 480px at 18% 60%, #000 0%, transparent 70%);
}

/* near field: real tesserae */
.mosaic-near {
  background-image:
    linear-gradient(135deg, rgba(255, 122, 69, 0.5) 0 14px, transparent 15px),
    linear-gradient(45deg, rgba(255, 194, 75, 0.35) 0 12px, transparent 13px),
    linear-gradient(135deg, rgba(55, 213, 179, 0.3) 0 10px, transparent 11px),
    linear-gradient(45deg, rgba(122, 162, 255, 0.35) 0 12px, transparent 13px);
  background-size: 210px 210px, 170px 170px, 260px 260px, 190px 190px;
  background-position: 12% 18%, 78% 8%, 62% 72%, 25% 80%;
  background-repeat: no-repeat;
  opacity: 0.85;
  filter: saturate(1.05);
}

.hero-inner { position: relative; }

.eyebrow {
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ochre);
  margin: 0 0 1.1rem;
}

.hero h1 {
  font-size: var(--step-4);
  font-weight: 700;
  letter-spacing: -0.035em;
  line-height: 1.04;
  margin: 0 0 1.4rem;
  max-width: 21ch;
}

.hero h1 .accent {
  color: var(--accent);
  position: relative;
  white-space: nowrap;
}

.lede {
  font-size: var(--step-1);
  line-height: 1.6;
  color: var(--ink-soft);
  max-width: 58ch;
  margin: 0 0 0.5rem;
}

.hero-caption {
  color: var(--muted);
  font-size: var(--step--1);
  max-width: 62ch;
  margin: 1.4rem 0 0;
}

/* ---- W1: event inspector ----------------------------------------------------- */

.w1 {
  display: grid;
  grid-template-columns: minmax(300px, 5fr) minmax(360px, 7fr);
  gap: 1.6rem;
  margin: 3rem 0 1rem;
  align-items: stretch;
}

.w1-stage {
  position: relative;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background:
    linear-gradient(160deg, rgba(255, 122, 69, 0.05), transparent 45%),
    var(--bg-panel);
  padding: 2.2rem 1.6rem 1.2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.4rem;
  min-height: 380px;
}

.w1-shadowring {
  position: absolute;
  inset: 14px;
  border: 1px dashed var(--line-strong);
  border-radius: calc(var(--radius) - 5px);
  pointer-events: none;
}

.w1-footnote {
  font-size: 0.7rem;
  color: var(--faint);
  margin: 0;
  text-align: center;
  max-width: 34ch;
  line-height: 1.5;
}

.w1-panel {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-raised);
  padding: 1.4rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
}

.w1-panel-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  flex-wrap: wrap;
}

.w1-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--ink);
  margin: 0;
}

.w1-target { display: flex; align-items: center; gap: 0.6rem; }
.w1-target-label {
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--faint);
}

.w1-hint { margin: 0; font-size: var(--step--1); color: var(--muted); }

.w1-code {
  margin: 0;
  font-size: 0.8rem;
  color: var(--teal);
  background: var(--bg-sunken);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 0.55rem 0.8rem;
  overflow-x: auto;
}

.w1-empty {
  margin: 0;
  font-size: 0.8rem;
  color: var(--faint);
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 1.1rem 0.9rem;
  text-align: center;
}

.w1-traces {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
  max-height: 300px;
  overflow-y: auto;
}

.w1-trace {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: 0.15rem 0.7rem;
  align-items: baseline;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-sm);
  padding: 0.55rem 0.75rem;
  background: var(--bg-sunken);
}

.w1-row-label {
  font-size: 0.62rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--faint);
}

.w1-row-value {
  font-size: 0.78rem;
  color: var(--ink-soft);
  overflow-wrap: anywhere;
}

.w1-params { color: var(--ochre); }

.w1-hop { color: var(--teal); border-color: var(--teal); }
.w1-trace:has(.w1-hop) { border-left-color: var(--teal); }

.w1-panel-foot {
  margin-top: auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  border-top: 1px dashed var(--line);
  padding-top: 0.8rem;
}

.w1-note { margin: 0; font-size: 0.75rem; color: var(--faint); max-width: 44ch; }

/* ---- 2. the seam ------------------------------------------------------------- */

.seam-stage {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: stretch;
  gap: 0;
  margin: 2rem 0 2.6rem;
  min-height: 120px;
}

.tile-group {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius) 0 0 var(--radius);
  position: relative;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 26px 26px;
}
.tile-group.right { border-radius: 0 var(--radius) var(--radius) 0; }
.tile-group.left { background-position: 6px 6px; }
.tile-group.right { background-position: 19px 9px; }

.tile-group-label {
  position: absolute;
  bottom: 0.7rem;
  left: 50%;
  translate: -50% 0;
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--faint);
  background: var(--bg);
  padding: 0.15rem 0.6rem;
  border: 1px solid var(--line);
  border-radius: 99px;
}

.seam-gap {
  position: relative;
  width: clamp(46px, 7vw, 90px);
  display: grid;
  place-items: center;
}

.seam-fill {
  position: absolute;
  inset-block: 8px;
  left: 50%;
  width: 2px;
  translate: -50% 0;
  background: linear-gradient(var(--accent), var(--ochre));
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.9s cubic-bezier(0.2, 0.7, 0.2, 1);
}
.seam-stage.in .seam-fill { transform: scaleY(1); }

.seam-gap-label {
  position: relative;
  z-index: 1;
  font-size: 0.66rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--accent);
  writing-mode: vertical-rl;
  background: var(--bg);
  padding: 0.5rem 0.1rem;
  border: 1px solid var(--line);
  border-radius: 99px;
}

/* ---- code figures --------------------------------------------------------------- */

.code-figure {
  margin: 1.6rem 0;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--bg-panel);
}

.code-figure figcaption {
  font-size: 0.7rem;
  color: var(--faint);
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--line);
  background: var(--bg-sunken);
  letter-spacing: 0.02em;
}

pre.code {
  margin: 0;
  padding: 1.05rem 1.2rem;
  overflow-x: auto;
  font-size: 0.8rem;
  line-height: 1.62;
  color: var(--ink-soft);
  tab-size: 2;
}

/* narrow multi-column cards: wrap instead of clipping long comment lines
   (must also target the inner <code>, which `pre code` resets to pre) */
pre.code.wrap,
pre.code.wrap code {
  white-space: pre-wrap;
  overflow-x: visible;
  word-break: break-word;
}

.code.strike { text-decoration: line-through; text-decoration-color: var(--red); text-decoration-thickness: 1.5px; opacity: 0.85; }
.accent-code pre.code, pre.code.accent-code { color: var(--teal); font-weight: 700; font-size: 0.95rem; }

.snippet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.4rem;
}
.snippet-grid.three { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.snippet-grid.two { grid-template-columns: repeat(auto-fit, minmax(min(100%, 520px), 1fr)); }
.snippet-grid .code-figure { margin: 0; }

/* ---- W2: morph + badkey ---------------------------------------------------------- */

.morph {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.4rem;
  perspective: 1400px;
  margin: 2.4rem 0 1rem;
}

.morph-pane {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-panel);
  padding: 0 0 0.4rem;
  overflow: hidden;
  transition: transform 0.25s ease, border-color 0.25s ease;
  will-change: transform;
}

.morph-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.13em;
  color: var(--ochre);
  margin: 0;
  padding: 0.65rem 1.1rem;
  border-bottom: 1px solid var(--line);
  background: var(--bg-sunken);
}

.morph-pane pre.code { font-size: 0.76rem; }

.ln {
  border-radius: 4px;
  padding: 0 3px;
  margin: 0 -3px;
  transition: background 0.18s ease, color 0.18s ease;
}
.ln.lit { background: rgba(255, 194, 75, 0.16); color: var(--ochre); outline: 1px solid rgba(255, 194, 75, 0.45); }

.morph-hint {
  color: var(--muted);
  font-size: var(--step--1);
  margin: 0 0 1.6rem;
  padding-left: 0.9rem;
  border-left: 2px solid var(--ochre);
}

.badkey {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
  padding: 1.1rem 1.3rem 0.9rem;
  background: var(--bg-sunken);
  margin: 1.8rem 0;
}

.badkey-row {
  display: flex;
  gap: 0.9rem;
  align-items: center;
  flex-wrap: wrap;
}

.badkey-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--faint);
  display: block;
  margin-bottom: 0.5rem;
}

#badkey-input {
  background: var(--bg-panel);
  border: 1px solid var(--line-strong);
  color: var(--ink);
  font-size: 0.85rem;
  padding: 0.5rem 0.8rem;
  border-radius: var(--radius-sm);
  min-width: 220px;
}
#badkey-input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }

.badkey-result { font-size: 0.8rem; color: var(--muted); min-height: 1.2em; }
.badkey-result.ok { color: var(--teal); }
.badkey-result.bad { color: var(--red); }

.badkey-footnote { font-size: 0.68rem; color: var(--faint); margin: 0.7rem 0 0; }

/* ---- pillars -------------------------------------------------------------------- */

.pillar-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.4rem;
  margin: 2.4rem 0 1.6rem;
}

.pillar {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-panel);
  padding: 1.6rem 1.5rem 1.3rem;
  position: relative;
  overflow: hidden;
}

/* each pillar gets a tile corner mark */
.pillar::before {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 46px;
  height: 46px;
  border-radius: 0 0 0 100%;
  background: linear-gradient(225deg, var(--tile, var(--accent)) 0 50%, transparent 50%);
  opacity: 0.28;
}
.pillar:nth-child(1) { --tile: var(--accent); }
.pillar:nth-child(2) { --tile: var(--ochre); }
.pillar:nth-child(3) { --tile: var(--teal); }

.pillar h3 { margin: 0 0 0.7rem; font-size: var(--step-1); letter-spacing: -0.01em; }
.pillar p { margin: 0; color: var(--muted); font-size: 0.95rem; }

.proof-line {
  font-size: var(--step--1);
  color: var(--faint);
  border-top: 1px dashed var(--line);
  padding-top: 1.1rem;
  max-width: var(--measure);
}
.proof-line a { color: var(--muted); text-decoration: underline; text-underline-offset: 3px; }

/* ---- W3: hostlab -------------------------------------------------------------------- */

.hostlab {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-panel);
  padding: 1.4rem 1.5rem 1.6rem;
  margin: 2.4rem 0;
}

.hostlab-tabs { margin-bottom: 1.2rem; }

.hostlab-stage {
  display: grid;
  grid-template-columns: minmax(240px, 2fr) minmax(320px, 3fr);
  gap: 1.6rem;
  align-items: start;
}

.hostlab-element {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 1.3rem 1.1rem 0.9rem;
  background: var(--bg-sunken);
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  align-items: center;
}

.hostlab-caption { font-size: 0.68rem; color: var(--faint); margin: 0; text-align: center; }

.hostlab-code .code-figure { margin: 0 0 1rem; }

.hostlab-note { font-size: var(--step--1); color: var(--muted); margin: 0; }

.hostlab-caption-main {
  margin: 1.3rem 0 0;
  text-align: center;
  font-size: var(--step--1);
  color: var(--faint);
  border-top: 1px dashed var(--line);
  padding-top: 1.1rem;
}

/* ---- W4: picker demo ----------------------------------------------------------------- */

.picker-demo {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-panel);
  padding: 1.3rem 1.5rem;
  margin: 2.2rem 0;
}

.picker-log { margin: 0.9rem 0 0; font-size: 0.8rem; color: var(--muted); }
.picker-log strong { color: var(--teal); font-weight: 700; }

/* ---- status (W5) ------------------------------------------------------------------------ */

.status-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
  gap: 1.4rem;
  margin: 2.4rem 0;
}

.status-col {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-panel);
  padding: 1.4rem 1.5rem;
}

.status-col h3 {
  margin: 0 0 0.9rem;
  font-size: 0.8rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--ochre);
}

.status-col ul { margin: 0; padding: 0; list-style: none; display: flex; flex-direction: column; gap: 0.65rem; }
.status-col li {
  font-size: 0.88rem;
  color: var(--ink-soft);
  padding-left: 1.1rem;
  position: relative;
}
.status-col li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.52em;
  width: 7px;
  height: 7px;
  border-radius: 2px;
  background: var(--line-strong);
}

.status-board {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.9rem;
}

.status-tile {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 0.7rem 1rem;
  font-size: 0.85rem;
  color: var(--ink-soft);
  background: var(--bg-sunken);
}

.status-dot {
  width: 9px;
  height: 9px;
  border-radius: 50%;
  flex: none;
}
.status-tile.ok .status-dot { background: var(--teal); box-shadow: 0 0 8px rgba(55, 213, 179, 0.55); }
.status-tile.ok { border-color: rgba(55, 213, 179, 0.35); }
.status-tile.amber .status-dot { background: var(--amber); box-shadow: 0 0 8px rgba(255, 184, 75, 0.55); animation: pulse 2.2s ease-in-out infinite; }
.status-tile.amber { border-color: rgba(255, 184, 75, 0.4); }

@keyframes pulse { 50% { opacity: 0.45; } }

.status-legend {
  font-size: 0.68rem;
  color: var(--faint);
  margin: 0.9rem 0 0;
}

/* ---- faq ------------------------------------------------------------------------------------ */

.faq-list {
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  max-width: 56rem;
}

.faq-item {
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--bg-panel);
  overflow: hidden;
}

.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: 1rem 1.3rem;
  font-weight: 600;
  font-size: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-family: var(--font-mono);
  color: var(--accent);
  font-size: 1.25rem;
  flex: none;
  transition: rotate 0.2s ease;
}
.faq-item[open] summary::after { rotate: 45deg; }
.faq-item[open] summary { border-bottom: 1px dashed var(--line); }

.faq-item p {
  margin: 0;
  padding: 1rem 1.3rem 1.2rem;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* ---- contribute ------------------------------------------------------------------------------- */

.help-list {
  list-style: none;
  margin: 1.6rem 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0.8rem;
  max-width: 62rem;
}

.help-list li {
  border-left: 3px solid var(--ochre);
  background: var(--bg-panel);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  padding: 0.75rem 1.1rem;
  color: var(--ink-soft);
  font-size: 0.95rem;
}

/* ---- reveal-on-scroll -------------------------------------------------------------------------- */
/* Hiding is applied only when JS is present (html.js); without JS everything shows. */

html.js .reveal {
  opacity: 0;
  translate: 0 22px;
  transition: opacity 0.6s ease, translate 0.6s cubic-bezier(0.2, 0.7, 0.2, 1);
}
html.js .reveal.in { opacity: 1; translate: 0 0; }

/* ---- responsive --------------------------------------------------------------------------------- */

@media (max-width: 900px) {
  .w1 { grid-template-columns: 1fr; }
  .hostlab-stage { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; gap: 1.6rem; }
  .seam-stage { grid-template-columns: 1fr; gap: 0.6rem; min-height: 0; }
  .tile-group { border-radius: var(--radius-sm); min-height: 84px; }
  .seam-gap { width: auto; height: 46px; }
  .seam-fill { inset: 8px 14px auto 14px; left: auto; translate: 0; width: auto; height: 2px; transform: scaleX(0); transform-origin: left; }
  .seam-stage.in .seam-fill { transform: scaleX(1); }
  .seam-gap-label { writing-mode: horizontal-tb; }
  .site-nav { justify-content: flex-start; }
}

/* ---- reduced motion ------------------------------------------------------------------------------ */

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .mosaic { transform: none !important; }
  .morph-pane { transform: none !important; transition: none; }
  .seam-fill { transition: none; transform: scaleY(1); }
  .status-tile.amber .status-dot { animation: none; }
  .btn { transition: none; }
  html.js .reveal { opacity: 1; translate: none; transition: none; }
  .ln { transition: none; }
}

/* ---- lit islands (tobor-kit v1.7.0 + vendored semtext da41ab9) ----------------------------------- */

/* semtext token values — the vendored vocabulary.css reads --sem-* and gates
   fallback hide/show on [data-sem-upgraded] (stamped by the runtime). Values
   mirror this site's dark editorial palette. */
:root {
  color-scheme: dark;
  --sem-bg: var(--bg-sunken);
  --sem-surface: var(--bg-raised);
  --sem-fg: var(--ink);
  --sem-muted: var(--muted);
  --sem-border: var(--line-strong);
  --sem-accent: var(--accent);
  --sem-accent-fg: #14100c;
  --sem-note-info: var(--blue);
  --sem-note-tip: var(--teal);
  --sem-note-warning: var(--amber);
  --sem-note-danger: var(--red);
  --sem-thought-observation: var(--blue);
  --sem-thought-reflection: #c79bff;
  --sem-thought-assumption: var(--amber);
  --sem-thought-mind-read: var(--teal);
  --sem-thought-tangent: var(--muted);
  --sem-thought-concern: var(--red);
  --sem-correct: var(--teal);
  --sem-wrong: var(--red);
  --sem-occluded: var(--faint);
}

/* hosts stay in normal flow before and after upgrade */
noizu-faq { display: block; }
sem-note, sem-facts, sem-code { display: block; }

/* quickstart CLI island (shadow DOM: theme via kit tokens + parts) */
.cli-wrap { margin: 1.6rem 0 0.4rem; max-width: 42rem; }
.cli-wrap noizu-cli-mockup {
  display: block;
  --tobor-kit-cli-font: var(--font-mono);
  --tobor-kit-cli-font-size: 0.9rem;
}
.cli-wrap noizu-cli-mockup::part(screen) {
  background: var(--bg-sunken);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  color: var(--ink-soft);
}
.cli-wrap noizu-cli-mockup::part(action) { font-family: var(--font-mono); }
.cli-note { margin: 0.5rem 0 0; font-size: var(--step--1); color: var(--faint); }

/* footer attribution island (shadow DOM: --noizu-footer-brand-* beat presets) */
.footer-attribution { margin-top: 1.2rem; display: flex; justify-content: center; }
.footer-attribution noizu-footer-brand {
  --noizu-footer-brand-fg: var(--muted);
  --noizu-footer-brand-brand-color: var(--accent);
  --noizu-footer-brand-font: var(--font-mono);
  --noizu-footer-brand-size: 0.8rem;
  --noizu-footer-brand-letter-spacing: 0.08em;
}

/* semtext pre-upgrade / no-JS fallback: the listing reads like any code block */
sem-code:not(:defined) {
  display: block;
  white-space: pre-wrap;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  background: var(--bg-sunken);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  padding: 1rem 1.2rem;
  color: var(--ink-soft);
  overflow-x: auto;
}
sem-note:not(:defined), sem-facts:not(:defined) { display: block; }
sem-code:not(:defined) pre { margin: 0; font: inherit; white-space: pre; background: none; border: 0; padding: 0; }

/* ---- two engines (#engines): tier cards, decision frame, parity table ---- */

.tier-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.1rem;
  margin: 1.6rem 0 0;
}

.tier-card {
  position: relative;
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem;
  overflow: hidden;
}

.tier-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--accent);
}

.tier-card + .tier-card::before { background: var(--teal); }

.tier-card h3 { margin: 0 0 0.7rem; font-size: var(--step-1); letter-spacing: -0.01em; }
.tier-card p { margin: 0 0 0.9rem; color: var(--muted); font-size: 0.95rem; }
.tier-card p:last-child { margin-bottom: 0; }

.tier-status {
  font-size: 0.72rem;
  color: var(--ochre);
  border-top: 1px dashed var(--line);
  padding-top: 0.8rem;
}

.tier-frame {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.1rem;
  margin: 1.4rem 0 0;
}

.tier-frame-col {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius);
  padding: 1.1rem 1.3rem;
}

.tier-frame-col h4 {
  margin: 0 0 0.7rem;
  font-size: var(--step-0);
  color: var(--ink);
}

.tier-frame-col ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--muted);
  font-size: 0.92rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.parity-figure { margin: 1.8rem 0 0.4rem; }

.parity-figure figcaption {
  font-size: 0.72rem;
  color: var(--faint);
  margin: 0 0 0.7rem;
  max-width: 76ch;
}

.parity-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.8rem;
  background: var(--bg-panel);
}

.parity-table th,
.parity-table td {
  border: 1px solid var(--line);
  padding: 0.55rem 0.8rem;
  text-align: left;
}

.parity-table thead th { color: var(--ink); background: var(--bg-sunken); }
.parity-table tbody th { color: var(--ink-soft); font-weight: 500; white-space: nowrap; }
.parity-table td { color: var(--muted); }
.parity-table tbody tr:last-child th,
.parity-table tbody tr:last-child td { color: var(--ink); font-weight: 500; }

/* contract-labeled subheading in the extend section */
.contract-h {
  margin: 2.4rem 0 0.4rem;
  font-size: var(--step-1);
  color: var(--ink);
}

@media (max-width: 640px) {
  .parity-table { font-size: 0.7rem; }
  .parity-table th, .parity-table td { padding: 0.4rem 0.5rem; }
}