/* YunHai landing — interactive "how it works" chapters
 * Three self-running, precise/technical demos. On-brand: navy + ivory, electric accent, mono data.
 */

/* ============ CHAPTER SHELL ============ */
.chapter {
  padding: clamp(72px, 9vw, 132px) var(--gutter);
  position: relative;
}
.chapter--light { background: var(--paper-0); }
.chapter--light + .chapter--light { border-top: 1px solid var(--hair); }
.chapter--dark {
  background: var(--ink-900);
  color: var(--paper-0);
}

.chapter__inner {
  max-width: var(--maxw);
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
  gap: clamp(36px, 5vw, 80px);
  align-items: center;
}
.chapter--rev .chapter__copy { order: 2; }
.chapter--rev .chapter__demo { order: 1; }
@media (max-width: 940px) {
  .chapter__inner { grid-template-columns: 1fr; gap: 40px; }
  .chapter--rev .chapter__copy { order: 1; }
  .chapter--rev .chapter__demo { order: 2; }
}

/* ---- Chapter copy ---- */
.chapter__kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 22px;
}
.chapter--dark .chapter__kicker { color: #7FB0FF; }
.chapter__kicker .i {
  font-size: 11px;
  color: var(--text-500);
  padding: 2px 7px;
  border: 1px solid var(--hair-strong);
  border-radius: var(--r-pill);
}
.chapter--dark .chapter__kicker .i { color: rgba(244,241,236,.6); border-color: var(--hair-dark); }

.chapter h2 {
  font-size: clamp(30px, 3.8vw, 50px);
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.04;
  color: var(--text-900);
  margin-bottom: 22px;
  max-width: 14ch;
}
.chapter--dark h2 { color: var(--paper-0); }
.chapter h2 .serif {
  font-family: var(--font-display);
  font-style: italic;
  font-weight: 400;
  letter-spacing: -0.01em;
}
.chapter h2 .accent { color: var(--accent); }

.chapter__lede {
  font-size: 17px;
  line-height: 1.6;
  color: var(--text-500);
  max-width: 44ch;
  margin-bottom: 26px;
}
.chapter--dark .chapter__lede { color: rgba(244,241,236,.6); }
.chapter__lede em { font-style: italic; color: var(--text-700); }
.chapter--dark .chapter__lede em { color: var(--paper-0); }

.chapter__points {
  list-style: none;
  margin: 0 0 30px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.chapter__points li {
  position: relative;
  padding-left: 22px;
  font-size: 14.5px;
  line-height: 1.5;
  color: var(--text-500);
}
.chapter--dark .chapter__points li { color: rgba(244,241,236,.6); }
.chapter__points li::before {
  content: '';
  position: absolute;
  left: 2px;
  top: 8px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  border: 1.5px solid var(--accent);
}
.chapter__points .b { color: var(--text-900); font-weight: 500; }
.chapter--dark .chapter__points .b { color: var(--paper-0); }

.chapter__replay {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 38px;
  padding: 0 16px 0 13px;
  border-radius: var(--r-pill);
  border: 1px solid var(--hair-strong);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-700);
  background: var(--paper-1);
  transition: all var(--dur-fast) var(--ease-out);
}
.chapter__replay svg { width: 15px; height: 15px; transition: transform var(--dur-med) var(--ease-out); }
.chapter__replay:hover { border-color: var(--text-900); color: var(--text-900); }
.chapter__replay:hover svg { transform: rotate(-180deg); }
.chapter--dark .chapter__replay {
  background: rgba(244,241,236,.06);
  border-color: var(--hair-dark);
  color: rgba(244,241,236,.85);
}
.chapter--dark .chapter__replay:hover { border-color: rgba(244,241,236,.4); color: var(--paper-0); }
.chapter__replay.is-playing { opacity: .5; pointer-events: none; }

/* ============ DEMO FRAME (shared) ============ */
.demo {
  border-radius: var(--r-xl);
  overflow: hidden;
  position: relative;
}
.demo--light {
  background: var(--paper-1);
  border: 1px solid var(--hair);
  box-shadow: var(--sh-lg);
}
.demo--dark {
  background: var(--ink-900);
  border: 1px solid rgba(244,241,236,.1);
  box-shadow: var(--sh-lg);
}

.demo__bar {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 13px 18px;
  border-bottom: 1px solid var(--hair);
  background: var(--paper-0);
}
.demo--dark .demo__bar { background: #0C1A30; border-bottom: 1px solid rgba(244,241,236,.08); }
.demo__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  gap: 7px;
  white-space: nowrap;
}
.demo--dark .demo__tag { color: #7FB0FF; }
.demo__bar .sp { flex: 1; }
.demo__stat {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  line-height: 1.1;
  min-width: 52px;
}
.demo__stat .k {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-400);
}
.demo--dark .demo__stat .k { color: rgba(244,241,236,.45); }
.demo__stat .v {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 500;
  font-feature-settings: 'tnum';
  color: var(--text-900);
  letter-spacing: -0.01em;
  white-space: nowrap;
  transition: color var(--dur-med);
}
.demo--dark .demo__stat .v { color: var(--paper-0); }
.demo__stat .v.is-hot { color: var(--accent); }

/* ============ DEMO 01 — PERSONALIZE ============ */
.pz {
  display: grid;
  grid-template-columns: 0.92fr 1.08fr;
  min-height: 392px;
}
@media (max-width: 540px) { .pz { grid-template-columns: 1fr; } }

.pz__feed {
  padding: 18px;
  border-right: 1px solid var(--hair);
  display: flex;
  flex-direction: column;
}
@media (max-width: 540px) { .pz__feed { border-right: 0; border-bottom: 1px solid var(--hair); } }
.pz__feedhead, .pz__rankhead {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-400);
  margin-bottom: 13px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.pz__signals { list-style: none; margin: 0 0 16px; padding: 0; display: flex; flex-direction: column; gap: 7px; }
.sig {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 8px 10px;
  border-radius: var(--r-sm);
  background: var(--paper-0);
  border: 1px solid var(--hair);
  font-size: 12px;
  color: var(--text-700);
  opacity: 0;
  transform: translateX(-8px);
  transition: opacity var(--dur-med) var(--ease-out), transform var(--dur-med) var(--ease-out);
}
.sig.in { opacity: 1; transform: none; }
.sig__ico {
  width: 16px; height: 16px;
  flex: none;
  display: inline-flex; align-items: center; justify-content: center;
  border-radius: 50%;
  font-size: 10px;
  font-family: var(--font-mono);
}
.sig--save .sig__ico { background: var(--accent-soft); color: var(--accent-deep); }
.sig--skip .sig__ico { background: #F1ECEA; color: var(--text-400); }
.sig--linger .sig__ico { background: #EAF3EC; color: var(--ok); }
.sig em { font-style: normal; color: var(--text-400); font-family: var(--font-mono); font-size: 10.5px; margin-left: auto; padding-left: 8px; }

.pz__profile { margin-top: auto; display: flex; flex-direction: column; gap: 9px; padding-top: 14px; border-top: 1px solid var(--hair); }
.pz__phead { font-family: var(--font-mono); font-size: 9.5px; letter-spacing: 0.14em; text-transform: uppercase; color: var(--text-400); margin-bottom: 2px; }
.pz__prow { display: grid; grid-template-columns: 58px 1fr; gap: 10px; align-items: center; }
.pz__prow span { font-family: var(--font-mono); font-size: 10.5px; color: var(--text-500); letter-spacing: 0.02em; }
.pz__track { height: 5px; border-radius: 3px; background: var(--paper-3); overflow: hidden; }
.pz__track i {
  display: block; height: 100%;
  width: var(--w0, 20%);
  background: var(--accent);
  border-radius: 3px;
  transition: width 900ms var(--ease-out);
}

.pz__rank { padding: 18px; display: flex; flex-direction: column; }
.pz__chip {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.06em;
  text-transform: none;
  color: var(--accent-deep);
  background: var(--accent-soft);
  border: 1px solid rgba(47,125,251,.2);
  border-radius: var(--r-pill);
  padding: 3px 9px;
  opacity: 0;
  transition: opacity var(--dur-med);
}
.pz__chip.in { opacity: 1; }
.pz__list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 7px; flex: 1; }
.rk {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 13px;
  border-radius: var(--r-md);
  background: var(--paper-0);
  border: 1px solid var(--hair);
  transition: border-color var(--dur-med), background var(--dur-med), box-shadow var(--dur-med);
}
.rk__num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-400);
  width: 16px;
  flex: none;
  font-feature-settings: 'tnum';
}
.rk__body { flex: 1; position: relative; min-width: 0; }
.rk__gen, .rk__you {
  display: block;
  font-size: 13px;
  font-weight: 500;
  color: var(--text-900);
  letter-spacing: -0.01em;
  line-height: 1.25;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: opacity var(--dur-med) var(--ease-out), transform var(--dur-med) var(--ease-out);
}
.rk__gen em, .rk__you em { font-style: normal; font-weight: 400; color: var(--text-400); font-size: 11px; }
.rk__you {
  position: absolute;
  inset: 0;
  opacity: 0;
  transform: translateY(8px);
}
.rk__you em { color: var(--accent); }
.rk__pct {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  color: var(--text-500);
  font-feature-settings: 'tnum';
  flex: none;
  transition: color var(--dur-med);
}
/* learned state */
.pz.learned .rk__gen { opacity: 0; transform: translateY(-8px); }
.pz.learned .rk__you { opacity: 1; transform: none; }
.pz.learned .rk { border-color: rgba(47,125,251,.22); background: var(--paper-1); }
.pz.learned .rk.is-top { border-color: var(--accent); box-shadow: 0 0 0 1px rgba(47,125,251,.25), var(--sh-md); }
.pz.learned .rk.is-top .rk__pct { color: var(--accent); }

/* ============ DEMO 02 — SEQUENCE (dark) ============ */
.sz { display: grid; grid-template-columns: 1fr; }
.sz__map { position: relative; aspect-ratio: 16 / 9; background: linear-gradient(180deg, #0A1628, #070B12); }
.sz__map::before {
  content: '';
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(244,241,236,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(244,241,236,.05) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: radial-gradient(ellipse 90% 85% at 50% 45%, #000 55%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 90% 85% at 50% 45%, #000 55%, transparent 100%);
}
.sz__svg { position: absolute; inset: 0; width: 100%; height: 100%; }
.sz__line { fill: none; stroke-linecap: round; stroke-linejoin: round; }
.sz__line--messy { stroke: rgba(244,241,236,.34); stroke-width: 2; stroke-dasharray: 3 7; transition: opacity 600ms var(--ease-out); }
.sz__line--opt {
  stroke: var(--accent); stroke-width: 2.5;
  filter: drop-shadow(0 0 6px rgba(47,125,251,.55));
  stroke-dasharray: var(--len); stroke-dashoffset: var(--len);
  opacity: 0;
}
.sz.opt .sz__line--messy { opacity: 0; }
.sz.opt .sz__line--opt { opacity: 1; animation: sz-draw 1500ms var(--ease-out) forwards; }
@keyframes sz-draw { to { stroke-dashoffset: 0; } }

.sz__pin circle.ring { fill: rgba(47,125,251,.12); stroke: rgba(47,125,251,.5); stroke-width: 1; }
.sz__pin circle.core { fill: var(--accent); }
.sz__pin text { font-family: var(--font-mono); font-size: 13px; font-weight: 600; fill: #fff; text-anchor: middle; dominant-baseline: central; }
.sz__pin .num-messy, .sz__pin .num-opt { transition: opacity 500ms; }
.sz__pin .num-opt { opacity: 0; }
.sz.opt .sz__pin .num-messy { opacity: 0; }
.sz.opt .sz__pin .num-opt { opacity: 1; }
.sz__runner { fill: #fff; filter: drop-shadow(0 0 6px rgba(255,255,255,.8)); opacity: 0; }
.sz.opt .sz__runner { opacity: 1; }

.sz__readout {
  position: absolute;
  left: 16px; bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: rgba(244,241,236,.7);
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.sz__readout .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); box-shadow: 0 0 8px var(--accent); animation: gm-pulse 1.2s infinite; }
.sz__badge {
  position: absolute;
  right: 16px; top: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--accent);
  background: rgba(47,125,251,.12);
  border: 1px solid rgba(47,125,251,.35);
  border-radius: var(--r-pill);
  padding: 5px 12px;
  opacity: 0;
  transform: translateY(-6px);
  transition: opacity var(--dur-med), transform var(--dur-med);
}
.sz.opt .sz__badge { opacity: 1; transform: none; }

.sz__metrics {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border-top: 1px solid rgba(244,241,236,.08);
}
.sz__metric { padding: 16px 18px; border-right: 1px solid rgba(244,241,236,.08); }
.sz__metric:last-child { border-right: 0; }
.sz__metric .mk { font-family: var(--font-mono); font-size: 9.5px; letter-spacing: 0.14em; text-transform: uppercase; color: rgba(244,241,236,.45); }
.sz__metric .mv {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 500;
  color: var(--paper-0);
  font-feature-settings: 'tnum';
  margin-top: 6px;
  letter-spacing: -0.01em;
  display: flex; align-items: baseline; gap: 7px;
}
.sz__metric .mv .from { font-size: 12px; color: rgba(244,241,236,.4); text-decoration: line-through; font-weight: 400; }
.sz__metric.is-win .mv { color: var(--accent); }
.sz__checkline {
  padding: 13px 18px;
  border-top: 1px solid rgba(244,241,236,.08);
  display: flex;
  gap: 22px;
  flex-wrap: wrap;
  font-family: var(--font-mono);
  font-size: 11px;
  color: rgba(244,241,236,.55);
}
.sz__checkline span { display: inline-flex; align-items: center; gap: 7px; opacity: 0; transition: opacity var(--dur-med); }
.sz__checkline span.in { opacity: 1; }
.sz__checkline .ck { color: var(--ok); }

/* ============ DEMO 03 — ORGANIZE ============ */
.az { display: grid; grid-template-columns: 1fr; }
.az__stage {
  position: relative;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 18px;
  align-items: center;
  padding: 26px 22px;
  min-height: 360px;
}
@media (max-width: 600px) { .az__stage { grid-template-columns: 1fr; } .az__arrow { display: none; } }

/* messy side */
.az__mess { position: relative; height: 250px; }
.az__scrap {
  position: absolute;
  background: var(--paper-0);
  border: 1px solid var(--hair-strong);
  border-radius: var(--r-sm);
  box-shadow: var(--sh-sm);
  padding: 9px 11px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--text-500);
  transition: opacity 600ms var(--ease-out), transform 600ms var(--ease-out);
  display: flex; align-items: center; gap: 7px;
}
.az__scrap .x { color: var(--err); font-size: 11px; }
.az__scrap--sheet {
  inset: 8px 30px 80px 6px;
  display: block;
  padding: 0;
  overflow: hidden;
}
.az__sheetbar { background: #1F8A5B; color: #fff; font-size: 9px; padding: 4px 8px; letter-spacing: .04em; }
.az__sheetgrid { display: grid; grid-template-columns: repeat(4, 1fr); }
.az__sheetgrid i { height: 16px; border-right: 1px solid var(--hair); border-bottom: 1px solid var(--hair); display: block; }
.az__sheetgrid i:nth-child(3n) { background: rgba(192,54,44,.06); }
.az.tidy .az__scrap { opacity: 0; transform: scale(.88) translateY(8px); }

/* arrow */
.az__arrow { display: flex; align-items: center; justify-content: center; color: var(--text-400); }
.az__arrow svg { width: 26px; height: 26px; }
.az.tidy .az__arrow { color: var(--accent); }

/* clean list */
.az__list { display: flex; flex-direction: column; gap: 8px; }
.az__listhead {
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-400);
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 3px;
}
.az__card {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 11px 13px;
  border-radius: var(--r-md);
  background: var(--paper-0);
  border: 1px solid var(--hair);
  opacity: 0;
  transform: translateY(10px);
  transition: opacity var(--dur-med) var(--ease-out), transform var(--dur-med) var(--ease-out);
}
.az__card.in { opacity: 1; transform: none; }
.az__check {
  width: 18px; height: 18px; flex: none;
  border-radius: 50%;
  background: var(--ok);
  display: inline-flex; align-items: center; justify-content: center;
}
.az__check svg { width: 11px; height: 11px; stroke: #fff; }
.az__card .ct { flex: 1; min-width: 0; }
.az__card .ct b { display: block; font-size: 13px; font-weight: 500; color: var(--text-900); letter-spacing: -0.01em; }
.az__card .ct span { font-family: var(--font-mono); font-size: 10.5px; color: var(--text-500); }
.az__tk {
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent-deep);
  background: var(--accent-soft);
  border: 1px solid rgba(47,125,251,.2);
  border-radius: var(--r-sm);
  padding: 3px 7px;
  flex: none;
}

.az__foot {
  border-top: 1px solid var(--hair);
  padding: 14px 20px;
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  background: var(--paper-0);
}
.az__avatars { display: flex; }
.az__avatars i {
  width: 26px; height: 26px; border-radius: 50%;
  border: 2px solid var(--paper-0);
  margin-left: -8px;
  font-family: var(--font-mono); font-size: 10px; font-weight: 600;
  color: #fff;
  display: inline-flex; align-items: center; justify-content: center;
  opacity: 0; transform: scale(.5);
  transition: opacity var(--dur-fast) var(--ease-out), transform var(--dur-fast) var(--ease-out);
}
.az__avatars i:first-child { margin-left: 0; }
.az__avatars i:nth-child(1) { background: #2F7DFB; }
.az__avatars i:nth-child(2) { background: #1F9D55; }
.az__avatars i:nth-child(3) { background: #C08B10; }
.az__avatars i:nth-child(4) { background: #7A5AF0; }
.az__avatars i.in { opacity: 1; transform: none; }
.az__share {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--text-500);
  letter-spacing: 0.02em;
}
.az__share b { color: var(--text-900); font-weight: 500; }
.az__pill {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ok);
  background: #EAF3EC;
  border: 1px solid rgba(31,157,85,.25);
  border-radius: var(--r-pill);
  padding: 5px 11px;
  display: inline-flex; align-items: center; gap: 7px;
  opacity: 0;
  transition: opacity var(--dur-med);
}
.az__pill.in { opacity: 1; }
.az__pill .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--ok); }