/* Spark Collective — site styles. All values trace to css/tokens.css. */
@font-face { font-family: "Syne"; src: url("../assets/fonts/Syne-Bold.woff2") format("woff2"); font-weight: 700; font-display: swap; }
@font-face { font-family: "Syne"; src: url("../assets/fonts/Syne-ExtraBold.woff2") format("woff2"); font-weight: 800; font-display: swap; }
@font-face { font-family: "ZCOOL QingKe HuangYou"; src: url("../assets/fonts/ZCOOLQingKeHuangYou-Regular.woff2") format("woff2"); font-weight: 400; font-display: swap; }

*, *::before, *::after { box-sizing: border-box; border-radius: var(--sc-radius); }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--sc-color-black); color: var(--sc-color-white);
  font-family: var(--sc-font-body); font-size: var(--sc-text-body); line-height: var(--sc-leading-body); }
img { display: block; max-width: 100%; image-orientation: from-image; }
a { color: inherit; }
:focus-visible { outline: var(--sc-border-width) solid var(--sc-color-red); outline-offset: 2px; }
.container { max-width: var(--sc-content-max); margin: 0 auto; padding: 0 var(--sc-space-4); }
@media (max-width: 768px) { .container { padding: 0 var(--sc-space-3); } }

/* ---------- nav ---------- */
.nav { position: fixed; inset: 0 0 auto 0; z-index: var(--sc-z-nav);
  display: flex; align-items: center; gap: var(--sc-space-4);
  padding: var(--sc-space-2) var(--sc-space-4);
  background: var(--sc-color-black); border-bottom: var(--sc-rule-weight) solid transparent;
  transition: border-color var(--sc-motion-instant) var(--sc-ease-stepped); }
.nav.scrolled { border-bottom-color: var(--sc-color-white); }
.nav .mark { height: 20px; width: auto; margin-right: auto; }
.nav a.navlink { text-decoration: none; font-family: var(--sc-font-display); font-weight: 500;
  font-size: 15px; padding: 4px 0; border-bottom: 2px solid transparent;
  transition: color var(--sc-motion-instant) var(--sc-ease-stepped); }
.nav a.navlink:hover { color: var(--sc-color-red); border-bottom-color: var(--sc-color-red); }
.lang-toggle { background: transparent; border: var(--sc-border-width) solid var(--sc-color-ash);
  color: var(--sc-color-white); font-family: var(--sc-font-display); font-weight: 700; font-size: 13px;
  padding: 4px 12px; cursor: pointer;
  transition: background var(--sc-motion-instant) var(--sc-ease-stepped), color var(--sc-motion-instant) var(--sc-ease-stepped); }
.lang-toggle:hover { background: var(--sc-color-white); color: var(--sc-color-black); }

/* ---------- mobile nav drawer (CSS-only, no JS required) ---------- */
.nav-menu { display: contents; }           /* desktop: children flow inline */
.nav-burger, #nav-open { display: none; }
@media (max-width: 900px) {                /* EN labels overflow below ~870px — drawer kicks in with margin */
  .nav { gap: var(--sc-space-2); }
  .nav-burger { display: block; width: 40px; height: 40px; cursor: pointer;
    position: relative; flex: none; }
  .nav-burger span { position: absolute; left: 8px; right: 8px; height: 2px;
    background: var(--sc-color-white); }
  .nav-burger span:nth-child(1) { top: 13px; }
  .nav-burger span:nth-child(2) { top: 19px; }
  .nav-burger span:nth-child(3) { top: 25px; }
  .nav-menu { display: flex; flex-direction: column; gap: var(--sc-space-3);
    position: fixed; top: 0; right: 0; bottom: 0; width: min(78vw, 320px);
    background: var(--sc-color-black); border-left: var(--sc-rule-weight) solid var(--sc-color-white);
    padding: 96px var(--sc-space-4) var(--sc-space-4);
    transform: translateX(100%); visibility: hidden; }
  #nav-open:checked ~ .nav-menu { transform: none; visibility: visible; }
  #nav-open:checked ~ .nav-burger span:nth-child(1) { top: 19px; transform: rotate(45deg); }
  #nav-open:checked ~ .nav-burger span:nth-child(2) { opacity: 0; }
  #nav-open:checked ~ .nav-burger span:nth-child(3) { top: 19px; transform: rotate(-45deg); }
  .nav-menu a.navlink { font-size: 20px; border-bottom: none; }
  /* language toggle stays in the persistent bar — always one tap away */
  .lang-toggle { flex: none; }
}

/* ---------- hero ---------- */
/* Height = pacing: taller region means the scrubbed sequence unfolds more
   slowly per scroll. 320vh ≈ 1.8x the original pace; mobile slightly shorter. */
.hero { position: relative; height: 400vh; }   /* ≈2.2x original pace */
@media (max-width: 768px) { .hero { height: 320vh; } }
.hero.compact { height: 100vh; } /* reduced-motion only */
.hero-stage { position: sticky; top: 0; height: 100vh; overflow: hidden; background: var(--sc-color-black); }
#hero-canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero-idle { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
  gap: var(--sc-space-3); }
.hero-idle img { width: min(46vw, 480px); height: auto; }
.hero-dot { width: 14px; height: 14px; background: var(--sc-color-red);
  animation: dotpulse 1.6s steps(4, end) infinite; }
@keyframes dotpulse { 0% { opacity: 1; transform: scale(1); } 50% { opacity: .45; transform: scale(.72); } 100% { opacity: 1; transform: scale(1); } }
.hero-copy { position: absolute; z-index: 2; right: var(--sc-space-6); left: auto; bottom: var(--sc-space-8);
  max-width: 560px; opacity: 0; visibility: hidden;
  /* hard-edged legibility panel — solid plane, no blur, kept subtle:
     the KV's right side is near-black, so this only firms up the worst case */
  background: rgba(0, 0, 0, 0.38); padding: var(--sc-space-3); }
.hero-copy.on { opacity: 1; visibility: visible; transition: opacity var(--sc-motion-fast) var(--sc-ease-stepped); }
.hero-copy h1 { font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif; font-weight: var(--sc-weight-display);
  font-size: clamp(30px, 3.6vw, var(--sc-text-h1)); line-height: var(--sc-leading-display); margin: 0 0 var(--sc-space-2); }
.hero-copy h1 .zh { font-family: var(--sc-font-display-zh); font-weight: 400; }
.hero-copy p { font-size: var(--sc-text-lead); margin: 0; color: var(--sc-color-ash); }
/* Scroll cue — shared by the homepage hero (.hero-scrollcue) and the About
   narrative (.an-cue); both elements also carry .scrollcue so the treatment
   lives in ONE place. Top band (clears the fixed nav; captions own the centre
   and lower band), white, one type step up from body, hidden until JS adds .on,
   hard step-out. Caret via ::after so the i18n textContent swap never wipes it.
   Pulse is a calmer twin of .hero-dot's dotpulse — stepped, opacity only. */
.scrollcue { position: absolute; z-index: 2; top: var(--sc-space-12); left: 50%; transform: translateX(-50%);
  margin: 0; font-size: var(--sc-text-lead); font-weight: var(--sc-weight-medium); letter-spacing: .08em;
  text-transform: uppercase; color: var(--sc-color-white); visibility: hidden; }
.scrollcue.on { visibility: visible; animation: cuepulse 1.6s steps(4, end) infinite; }
.scrollcue::after { content: "\2193"; display: block; text-align: center; margin-top: 4px; font-size: 14px; line-height: 1; }
@keyframes cuepulse { 0% { opacity: 1; } 50% { opacity: .6; } 100% { opacity: 1; } }
@media (max-width: 768px) {
  .hero-copy { left: var(--sc-space-3); right: var(--sc-space-3); bottom: var(--sc-space-6); }
  .hero-idle img { width: 70vw; }
}

/* ---------- sections ---------- */
.section { padding: var(--sc-space-12) 0; }
.kicker { font-size: var(--sc-text-caption); letter-spacing: .1em; text-transform: uppercase;
  color: var(--sc-color-ash); margin: 0 0 var(--sc-space-2); }
h2.sec { font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif; font-weight: var(--sc-weight-display);
  font-size: var(--sc-text-h2); line-height: var(--sc-leading-heading); margin: 0 0 var(--sc-space-4);
  padding-top: var(--sc-space-3); border-top: var(--sc-rule-weight) solid var(--sc-color-white); }
.grid { display: grid; gap: var(--sc-space-3); }
.grid.g3 { grid-template-columns: repeat(3, 1fr); }
.grid.g2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 1080px) { .grid.g3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 768px) { .grid.g3, .grid.g2 { grid-template-columns: 1fr; } }

.card { border: var(--sc-border-width) solid var(--sc-color-ash); padding: var(--sc-space-3);
  display: flex; flex-direction: column; text-decoration: none;
  transition: border-color var(--sc-motion-instant) var(--sc-ease-stepped); }
.card:hover { border-color: var(--sc-color-white); }
.card.raised { background: var(--sc-color-ember); border-color: transparent; }
.card h3 { font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif; font-weight: 700; font-size: var(--sc-text-h3);
  margin: 0 0 var(--sc-space-1); }
.card h3 .zh { font-family: var(--sc-font-display-zh); font-weight: 400; color: var(--sc-color-red); }
.card.raised h3 .zh { color: var(--sc-color-white); }
.card p { margin: 0 0 var(--sc-space-2); color: var(--sc-color-ash); }
.card.raised p { color: var(--sc-color-white); }
.card .cta { margin-top: auto; font-family: var(--sc-font-display); font-weight: 700; font-size: 15px;
  color: var(--sc-color-white); }
.card:hover .cta { color: var(--sc-color-red); }
.card img.thumb { margin: calc(-1 * var(--sc-space-3)) calc(-1 * var(--sc-space-3)) var(--sc-space-3);
  width: calc(100% + 2 * var(--sc-space-3)); max-width: none; image-rendering: pixelated; }
.date { font-size: var(--sc-text-caption); color: var(--sc-color-ash); text-transform: uppercase;
  letter-spacing: .08em; margin: 0 0 var(--sc-space-1); }

/* ---------- Langhua Showcase (layered KV composition) ----------
   Dominant KV with "Langhua" overlaid; a smaller copy card raised into the
   bottom-right corner, backed by an offset ash plane (depth = colour plane,
   no shadow). .lh-copy is a positioning frame; ::before draws the plane FIRST
   so the white panel paints over it and only the offset edge shows. */
.lh-showcase { position: relative; padding-top: var(--sc-space-3);
  border-top: var(--sc-rule-weight) solid var(--sc-color-white); }
.lh-kv { position: relative; width: 100%; aspect-ratio: 16 / 7; background: var(--sc-color-ash); }
.lh-kv img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.lh-kv-mark { position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%);
  font-family: var(--sc-font-display); font-weight: var(--sc-weight-heading); color: var(--sc-color-black);
  letter-spacing: .04em; font-size: var(--sc-text-lead); text-align: center; padding: 0 var(--sc-space-3); }
.lh-title { position: absolute; left: var(--sc-space-4); top: var(--sc-space-3); right: var(--sc-space-4);
  margin: 0; z-index: 2; font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif; font-weight: var(--sc-weight-display);
  font-size: clamp(44px, 7vw, 88px); line-height: var(--sc-leading-display); color: var(--sc-color-white); }
.lh-copy { position: relative; z-index: 3; width: min(320px, 38%);
  margin: calc(-1 * var(--sc-space-16)) 0 0 auto; }
.lh-copy::before { content: ""; position: absolute; inset: 0;
  transform: translate(var(--sc-space-2), var(--sc-space-2)); background: var(--sc-color-ash); }
.lh-copy__panel { position: relative; background: var(--sc-color-white); padding: var(--sc-space-3);
  display: flex; flex-direction: column; justify-content: space-between; min-height: clamp(180px, 19vw, 230px); }
.lh-copy__panel p { margin: 0 0 var(--sc-space-3); color: var(--sc-color-black); }
.lh-copy__panel .cta { font-family: var(--sc-font-display); font-weight: 700; font-size: 15px; color: var(--sc-color-black); text-decoration: none; }
.lh-copy__panel .cta:hover { color: var(--sc-color-red); }
@media (max-width: 768px) {
  .lh-title { font-size: clamp(36px, 11vw, 52px); left: var(--sc-space-3); right: var(--sc-space-3); }
  .lh-copy { width: 100%; margin: var(--sc-space-3) 0 0 0; }
  .lh-copy__panel { min-height: 0; }
  .lh-copy::before { transform: translate(var(--sc-space-1), var(--sc-space-1)); }
}

/* ---------- About particle narrative (Signal → Momentum → System) ----------
   Engine: js/about-narrative.js (lazy-loaded from about.html). Region height
   = pacing, same principle as the hero. The stage stays display:none until
   the loader arms it, so no-JS and reduced-motion visitors only ever see the
   static framework text below it. */
html { overflow-x: clip; } /* full-bleed breakout uses 50vw margins; clips the
                              scrollbar-width sliver on Windows */
.an-region { display: none; }
.an-region.armed { display: block; position: relative; height: 600vh;
  margin-left: calc(50% - 50vw); margin-right: calc(50% - 50vw); }
@media (max-width: 768px) { .an-region.armed { height: 400vh; } }
.an-stage { position: sticky; top: 0; height: 100vh; overflow: hidden;
  background: var(--sc-color-black); }
#an-canvas { position: absolute; inset: 0; width: 100%; height: 100%; }
/* .an-cue styling now comes from the shared .scrollcue recipe (see hero block). */
.an-cap { position: absolute; z-index: 2; left: 50%; top: 50%;
  transform: translate(-50%, -50%); margin: 0; text-align: center;
  max-width: 20ch; width: max-content;
  font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif;
  font-weight: var(--sc-weight-display);
  font-size: clamp(24px, 2.6vw, var(--sc-text-h3));
  line-height: var(--sc-leading-heading); visibility: hidden; }
.an-cap--low { top: 78%; } /* S5: clears the seal assembling at centre */
/* Mobile: captions must wrap inside the viewport, not run off both edges.
   (Desktop uses width:max-content + 20ch; on a phone the long lines overflow.) */
@media (max-width: 768px) {
  .an-cap { width: auto; max-width: 90vw; font-size: clamp(18px, 5vw, 24px); }
}
.an-words { position: absolute; z-index: 2; left: 50%; top: 50%;
  transform: translate(-50%, -50%); margin: 0; text-align: center;
  white-space: nowrap; font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif;
  font-weight: var(--sc-weight-display); text-transform: uppercase;
  /* sized to the string, not the viewport: 26 wide Syne-800 glyphs must fit
     inside the stage at every width (Langhua lesson — vw display text clips).
     The canvas samples this element's computed size, so particles and DOM
     words always match. */
  letter-spacing: .06em; font-size: clamp(18px, 3.2vw, 46px);
  max-width: 94vw; visibility: hidden; }
/* Mobile: stack the payoff (Signal / · / Momentum / · / System) so it can't run
   off a phone. Must sit AFTER the base .an-words rule to win on source order.
   about-narrative.js builds the .wl (word) / .wd (dot) spans and mirrors this
   stacked layout in the particle sampler so the resolve still matches. */
@media (max-width: 768px) {
  .an-words { white-space: normal; max-width: 90vw; font-size: clamp(24px, 7vw, 30px); line-height: 1.06; }
  .an-words .wl { display: block; }
  .an-words .wd { display: block; font-size: 0.55em; line-height: 1.5; }
}
.an-cue.on, .an-cap.on, .an-words.on { visibility: visible; } /* hard steps, no fades */
.an-framework { padding-top: var(--sc-space-8); }
.an-fw-word { font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif;
  font-weight: var(--sc-weight-heading); font-size: var(--sc-text-lead);
  margin: 0 0 var(--sc-space-1); color: var(--sc-color-red); }
.an-fw-p { margin: 0; color: var(--sc-color-ash); }
@media (prefers-reduced-motion: reduce) {
  .an-region, .an-region.armed { display: none; }
  .an-framework { padding-top: 0; }
}

/* ---------- Case study page (brands.html) ----------
   Modular block architecture: .cs-block is the reusable case-study skeleton
   (ID header required · narrative sections optional · block close optional).
   A second, compact case study = one more .cs-block after the divider slot
   at the bottom of brands.html — no new CSS needed. Engine: js/brands.js.
   Section rhythm here is deliberately tighter than .section (Step 2 sign-off:
   the next section's top edge peeks in before the current one ends). */
.cs-section { padding: var(--sc-space-8) 0; }
.cs-col { max-width: 720px; margin-left: auto; margin-right: auto; } /* centred BLOCK, left-ragged text */
.cs-manifesto { font-size: var(--sc-text-lead); color: var(--sc-color-ash); margin: var(--sc-space-3) 0 0; }
.cs-manifesto b { color: var(--sc-color-white); }
.cs-manifesto .cs-proof { color: var(--sc-color-red); font-weight: var(--sc-weight-heading); }
/* the four terms tick to emphasis one-by-one (js); no-JS = already emphasised */
.cs-manifesto .cs-term { color: var(--sc-color-white); font-weight: var(--sc-weight-heading); }
.sc-motion .cs-manifesto .cs-term:not(.on) { color: var(--sc-color-ash); font-weight: var(--sc-weight-body); }
.cs-manifesto .cs-term.on { transition: color var(--sc-motion-fast) var(--sc-ease-stepped); }

/* W1 — product reveal stage (full-bleed breakout, same mechanic as .an-region) */
.cs-stage { position: relative; margin-left: calc(50% - 50vw); margin-right: calc(50% - 50vw);
  min-height: 62vh; background: var(--sc-color-black);
  border-top: var(--sc-rule-weight) solid var(--sc-color-white);
  border-bottom: var(--sc-rule-weight) solid var(--sc-color-white);
  display: flex; align-items: center; justify-content: center; overflow: hidden; }
.cs-stage .cs-wordmark { position: absolute; left: 4%; top: 6%; z-index: 2; margin: 0;
  font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif; font-weight: var(--sc-weight-display);
  font-size: clamp(44px, 8vw, 104px); line-height: var(--sc-leading-display); }
.cs-stage .cs-wordmark .zh { display: block; font-family: var(--sc-font-display-zh);
  font-weight: 400; font-size: .48em; color: var(--sc-color-red); }
/* wordmark slice reveal — states only exist once js arms the stage (.cs-anim),
   so no-JS/reduced-motion always see the resolved lockup. Hard steps, no fades. */
.cs-stage.cs-anim .cs-wordmark .zh:not(.on),
.cs-stage.cs-anim .cs-spec:not(.on) { visibility: hidden; }
.cs-stage .cs-spec { position: absolute; left: 4%; bottom: var(--sc-space-3); z-index: 2; margin: 0;
  font-size: var(--sc-text-caption); letter-spacing: .12em; text-transform: uppercase; }
.cs-hero-img { width: min(340px, 44vw); }
.cs-hero-img img { width: 100%; height: auto; }
/* interim panel until the hero product shot lands — flat colour plane, no label */
.cs-hero-ph { width: min(300px, 42vw); aspect-ratio: 1 / 2.2; background: var(--sc-color-ember); }

/* W2 — Signal: dot clusters (About-page idiom, static end state) + cards */
.cs-signals { position: relative; margin-top: var(--sc-space-6); }
.cs-lattice { position: absolute; top: 100px; left: 16%; right: 16%; height: 2px;
  background: var(--sc-color-ash); opacity: .4; }
.cs-sig-cols { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--sc-space-4);
  position: relative; max-width: 1080px; margin: 0 auto; }
.cs-cluster { height: 200px; display: flex; align-items: center; justify-content: center; }
.cs-cluster:empty { height: 0; } /* no-JS: decorative clusters collapse, cards remain */
.cs-sig-card { border: var(--sc-border-width) solid var(--sc-color-ash);
  border-top-color: var(--sc-color-red); padding: var(--sc-space-3); }
.cs-sig-card .cs-num { font-family: var(--sc-font-display); font-weight: var(--sc-weight-display);
  color: var(--sc-color-red); font-size: var(--sc-text-h3); margin: 0 0 var(--sc-space-1); }
.cs-sig-card b { display: block; margin: 0 0 var(--sc-space-1); }
.cs-sig-card p { margin: 0; color: var(--sc-color-ash); font-size: 15px; }
/* signals sequence: the clusters themselves ASSEMBLE via js (scroll-scrubbed
   dot convergence — they're never hidden); only the CARDS use hidden states,
   and only under html.sc-motion, so no-JS shows everything resolved */
.sc-motion .cs-signals .cs-sig-card:not(.in) { opacity: 0; transform: translateY(8px); }
.cs-signals .cs-sig-card.in { opacity: 1; transform: none;
  transition: opacity var(--sc-motion-fast) var(--sc-ease-stepped),
              transform var(--sc-motion-fast) var(--sc-ease-stepped); }
.cs-closer { text-align: center; font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif;
  font-weight: var(--sc-weight-display); font-size: var(--sc-text-h3);
  margin: var(--sc-space-12) 0 0; }
.cs-closer .cs-red { color: var(--sc-color-red); }

/* W3 — Momentum: one image above the H2, restrained one-shot stat */
.cs-topimg { margin-bottom: var(--sc-space-6); }
.cs-topimg img { width: 100%; max-height: 38vh; object-fit: cover; }
.cs-topimg-ph { width: 100%; height: 30vh; background: var(--sc-color-ember); } /* interim, see cs-hero-ph */
.cs-body p { color: var(--sc-color-ash); }
.cs-body p b, .cs-body p .cs-strong { color: var(--sc-color-white); font-weight: var(--sc-weight-heading); }
.cs-stat { margin: var(--sc-space-6) 0; padding-left: var(--sc-space-3);
  border-left: 3px solid var(--sc-color-red); }
.cs-stat .cs-stat-n { font-family: var(--sc-font-display); font-weight: var(--sc-weight-display);
  font-size: clamp(40px, 6vw, 64px); line-height: 1; font-variant-numeric: tabular-nums; }
.cs-stat .cs-stat-w { font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif;
  font-weight: var(--sc-weight-heading); font-size: var(--sc-text-h3); margin-left: var(--sc-space-1); }
.cs-stat .cs-stat-c { margin: var(--sc-space-1) 0 0; font-size: var(--sc-text-caption);
  letter-spacing: .12em; text-transform: uppercase; color: var(--sc-color-ash); }
.cs-mclose { font-size: var(--sc-text-lead); color: var(--sc-color-white); margin-top: var(--sc-space-4); }
.cs-mclose .cs-red { color: var(--sc-color-red); font-weight: var(--sc-weight-heading); font-style: normal; }

/* W4 — System: three build steps, scroll-driven & reversible (js adds .cs-on).
   Steps are never hidden — undone steps sit dimmed, landing = full strength.
   Hard state change only, no movement. */
.cs-step { display: grid; grid-template-columns: 120px 1fr 1.4fr; gap: var(--sc-space-4);
  padding: var(--sc-space-6) 0; border-top: var(--sc-rule-weight) solid var(--sc-color-ash); }
.sc-motion .cs-step:not(.cs-on) { opacity: .3; }
.cs-step.cs-on { opacity: 1; transition: opacity var(--sc-motion-fast) var(--sc-ease-stepped); }
.cs-ind { display: flex; flex-direction: column; align-items: flex-start; }
.cs-ind .cs-num { font-family: var(--sc-font-display); font-weight: var(--sc-weight-display);
  font-size: var(--sc-text-h3); color: var(--sc-color-red); }
.cs-ind .cs-word { font-size: var(--sc-text-caption); letter-spacing: .14em;
  text-transform: uppercase; font-weight: var(--sc-weight-heading); margin-top: 2px; }
.cs-ind .cs-rail { flex: 1; width: var(--sc-rule-weight); min-height: var(--sc-space-6);
  background: var(--sc-color-ash); opacity: .4; margin: var(--sc-space-2) 0 0 10px; }
.cs-step.cs-on .cs-rail { background: var(--sc-color-red); opacity: 1;
  transition: background var(--sc-motion-fast) var(--sc-ease-stepped); }
.cs-step > p { margin: 0; color: var(--sc-color-ash); }
.cs-step > p b { color: var(--sc-color-white); }
.cs-graphic { position: relative; min-height: 260px; overflow: hidden;
  display: flex; align-items: center; justify-content: center; }
.cs-graphic img { width: 100%; height: 100%; object-fit: cover; position: absolute; inset: 0; }
.cs-graphic-ph { background: var(--sc-color-ember); } /* interim team-photo panel */
/* Langhua VI specimen (step 2): brand-bible Ruby Yangmei palette, ≤3 colours,
   no gradients — a contained specimen of Langhua's identity, not Spark UI */
.cs-vi-waves { background: #E3C1D0; }
.cs-vi-waves svg { position: absolute; inset: 0; width: 100%; height: 100%; }
.cs-vi-emblem { position: relative; z-index: 1; border: var(--sc-border-width) solid #5B2A3E;
  color: #5B2A3E; padding: var(--sc-space-2) var(--sc-space-3); text-align: center;
  font-family: var(--sc-font-display); font-weight: var(--sc-weight-heading);
  font-size: var(--sc-text-caption); letter-spacing: .18em; text-transform: uppercase;
  background: #E3C1D0; }
/* content grid (step 3): photo tiles + Langhua colour blocks/type for rhythm */
.cs-tiles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px;
  width: min(360px, 86%); margin: var(--sc-space-4) auto; }
.cs-tiles > * { aspect-ratio: 1; display: flex; align-items: center; justify-content: center;
  font-family: var(--sc-font-display-zh); font-size: var(--sc-text-h3); overflow: hidden; }
.cs-tiles img { position: static; width: 100%; height: 100%; object-fit: cover; }
.cs-springboard { border-top: var(--sc-rule-weight) solid var(--sc-color-ash);
  padding-top: var(--sc-space-6); margin: 0 auto; max-width: 900px;
  font-family: "Syne", "ZCOOL QingKe HuangYou", sans-serif;
  font-weight: var(--sc-weight-display); font-size: var(--sc-text-h3);
  line-height: var(--sc-leading-heading); }
.cs-springboard .cs-red { color: var(--sc-color-red); }

/* case-study divider — ships hidden until a second case study is live */
.cs-divider { border-top: var(--sc-rule-weight) solid var(--sc-color-white);
  padding-top: var(--sc-space-3); margin-top: var(--sc-space-12); }

@media (max-width: 820px) {
  .cs-sig-cols { grid-template-columns: 1fr; }
  .cs-lattice { display: none; }
  .cs-cluster { height: 150px; }
  .cs-step { grid-template-columns: 1fr; padding: var(--sc-space-4) 0; }
  .cs-ind { flex-direction: row; align-items: baseline; gap: var(--sc-space-2); }
  .cs-ind .cs-rail { display: none; }
  .cs-stage { min-height: 52vh; }
}


/* ---------- footer ---------- */
footer { border-top: var(--sc-rule-weight) solid var(--sc-color-white); padding: var(--sc-space-6) 0; margin-top: var(--sc-space-12); }
footer .row { display: flex; align-items: center; gap: var(--sc-space-4); flex-wrap: wrap; }
footer img { height: 18px; width: auto; }
footer p { margin: 0; font-size: var(--sc-text-caption); color: var(--sc-color-ash); }
footer .tagline { color: var(--sc-color-white); }

/* ---------- motion system (see js/motion.js + README) ----------
   Initial hidden states apply ONLY under html.sc-motion, which motion.js adds
   when JS runs and reduced-motion is off — no JS means nothing is ever hidden. */
.sc-motion [data-animate="rise-in"]:not(.in),
.sc-motion [data-animate="stagger-in"] > *:not(.in) {
  opacity: 0; transform: translateY(8px); }
[data-animate="rise-in"].in,
[data-animate="stagger-in"] > .in {
  opacity: 1; transform: none;
  transition: opacity var(--sc-motion-fast) var(--sc-ease-stepped),
              transform var(--sc-motion-fast) var(--sc-ease-stepped); }

/* ignite hover for links in body copy — consistent with nav/cards */
main p a { text-decoration: underline; text-underline-offset: 3px;
  transition: color var(--sc-motion-instant) var(--sc-ease-stepped); }
main p a:hover { color: var(--sc-color-red); }

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero-dot, .scrollcue.on { animation: none; }
  * { transition-duration: 0ms !important; }
}