/* ────────────────────────────────────────────────
   STICKER SYSTEM — shared visual layer
   Extracted from sticker.html (the style reference).
   Apple iOS page language: white / #f5f5f7 bands /
   black dark band / #0071e3. Every page that links
   this file must use its classes verbatim so the
   whole project reads as one visual system.
──────────────────────────────────────────────── */
:root{
  --seed-bg:#ffffff;
  --seed-fg:#1d1d1f;
  --seed-primary:#0071e3;
  --seed-surface:#f5f5f7;
  --seed-radius:18px;
  --seed-motion:1;
  --white:#ffffff;
  --black:#000000;
  --dark-card:#1d1d1f;
  --dark-card-hover:#2a2a2c;
  --dark-fg:#f5f5f7;

  /* derived */
  --paper:var(--seed-bg);
  --ink:var(--seed-fg);
  --accent:var(--seed-primary);
  --ink2:color-mix(in srgb,var(--seed-fg) 82%,var(--seed-bg));
  --muted:color-mix(in srgb,var(--seed-fg) 56%,var(--seed-bg));
  --muted2:color-mix(in srgb,var(--seed-fg) 40%,var(--seed-bg));
  --line:color-mix(in srgb,var(--seed-fg) 10%,transparent);
  --line-strong:color-mix(in srgb,var(--seed-fg) 16%,transparent);
  --accent-soft:color-mix(in srgb,var(--seed-primary) 10%,transparent);
  --accent-soft2:color-mix(in srgb,var(--seed-primary) 18%,transparent);
  --card:var(--seed-surface);
  --card-hover:color-mix(in srgb,var(--seed-fg) 3%,var(--seed-surface));
  --shadow:0 12px 32px -12px color-mix(in srgb,var(--seed-fg) 16%,transparent);

  --r-card:var(--seed-radius);
  --r-media:calc(var(--seed-radius) * .8);
  --r-chip:calc(var(--seed-radius) * .66);
  --r-pill:980px;

  --sans:-apple-system,BlinkMacSystemFont,"SF Pro Display","SF Pro Text","Segoe UI",Roboto,"Helvetica Neue",Helvetica,Arial,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --cjk:-apple-system,BlinkMacSystemFont,"SF Pro Display","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  --e-out:cubic-bezier(.25,.1,.25,1);
  --e-io:cubic-bezier(.76,0,.24,1);
  --rise:calc(clamp(18px,2.4vw,30px) * var(--seed-motion));
  --dur:calc(.8s * var(--seed-motion) + .01s);
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--sans);background:var(--paper);color:var(--ink);
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
  overflow-x:hidden;font-weight:400;line-height:1.47;letter-spacing:-.022em;
  font-size:17px;
}
::selection{background:var(--accent);color:var(--white)}
img,svg{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
button{font-family:inherit}

/* ============ PROGRESS + GRID ============ */
.progress{position:fixed;top:0;left:0;width:100%;height:2px;z-index:130;pointer-events:none;
  background:var(--accent);transform:scaleX(0);transform-origin:0 50%}
.wrap{max-width:1080px;margin:0 auto;padding:0 clamp(22px,5vw,80px)}
section{position:relative}

/* ============ TYPE HELPERS ============ */
.accent{color:var(--accent)}
.eyebrow{font-size:12px;font-weight:600;letter-spacing:.02em;text-transform:uppercase;color:var(--muted)}

/* ============ LANG BUTTON ============ */
.lang-btn{position:fixed;right:24px;bottom:24px;top:auto;z-index:100000;
  display:inline-flex;align-items:center;justify-content:center;
  width:48px;height:48px;padding:0;border-radius:50%;
  font:600 13px/1 var(--sans);letter-spacing:.06em;cursor:pointer;color:var(--ink);
  background:color-mix(in srgb,var(--seed-bg) 72%,transparent);
  border:1px solid color-mix(in srgb,var(--seed-fg) 14%,transparent);
  box-shadow:0 6px 20px rgba(29,29,31,.12);
  backdrop-filter:blur(14px) saturate(1.8);-webkit-backdrop-filter:blur(14px) saturate(1.8);
  transition:color .25s,background .25s,border-color .25s,transform .2s}
.lang-btn:hover{color:var(--accent);background:color-mix(in srgb,var(--seed-bg) 90%,transparent);border-color:color-mix(in srgb,var(--seed-fg) 24%,transparent)}
.lang-btn:active{transform:translateY(1px)}
@media(max-width:820px){.lang-btn{right:16px;bottom:16px;width:44px;height:44px;font-size:12px}}

/* ============ NAV (slim, frosted) ============ */
nav{position:sticky;top:0;z-index:100;background:color-mix(in srgb,var(--seed-bg) 72%,transparent);
  backdrop-filter:saturate(1.8) blur(20px);-webkit-backdrop-filter:saturate(1.8) blur(20px)}
.nav-in{max-width:1080px;margin:0 auto;padding:0 clamp(22px,5vw,80px);height:48px;display:flex;align-items:center;gap:24px}
.logo{font-family:var(--cjk);font-weight:600;font-size:14px;letter-spacing:-.01em;display:flex;align-items:baseline}
.logo .d{color:var(--accent);padding:0 1px}
.nav-links{display:flex;gap:2px;margin-left:auto}
.nav-links a{font-size:12px;font-weight:400;color:color-mix(in srgb,var(--seed-fg) 80%,transparent);letter-spacing:-.01em;
  display:flex;gap:5px;align-items:baseline;padding:6px 10px;border-radius:var(--r-pill);
  transition:color .2s,background .2s}
.nav-links a i{font-style:normal;font-size:10px;font-weight:600;color:var(--muted2);transition:color .2s}
.nav-links a:hover{color:var(--ink)}
.nav-links a.on{color:var(--ink)}
.nav-links a.on i{color:var(--accent)}
.nav-cta{font-size:12px;font-weight:500;color:var(--white);background:var(--accent);
  padding:7px 16px;border-radius:var(--r-pill);letter-spacing:-.01em;
  transition:background .2s,transform .2s var(--e-out)}
.nav-cta:hover{background:color-mix(in srgb,var(--seed-primary) 86%,var(--white));transform:translateY(-1px)}
@media(max-width:880px){.nav-links{display:none}.nav-cta{margin-left:auto}}

/* ============ HERO (centered, one viewport) ============ */
.hero{min-height:calc(100vh - 48px);min-height:calc(100svh - 48px);display:flex;align-items:center;
  padding:clamp(64px,9vh,100px) 0 clamp(48px,7vh,84px);overflow:hidden}
.hero-fx{position:absolute;inset:0;z-index:0;pointer-events:none}
.hero .wrap{position:relative;z-index:1;max-width:1080px;width:100%}
.hero-center{display:flex;flex-direction:column;align-items:center;text-align:center}
.eyebrow-row{display:flex;flex-wrap:wrap;justify-content:center;gap:8px 32px;margin-bottom:clamp(20px,3.4vh,32px)}
.eyebrow-row span{display:inline-flex;align-items:baseline;gap:7px;
  font-size:14px;font-weight:400;letter-spacing:-.01em;color:var(--muted)}
.eyebrow-row b{color:var(--ink);font-weight:600}
.wordmark{font-family:var(--cjk);font-weight:700;font-size:clamp(52px,8vw,112px);line-height:1.04;letter-spacing:-.025em;color:var(--ink)}
.hero .kick{margin-top:clamp(16px,2.6vh,26px);font-size:clamp(19px,2vw,27px);font-weight:600;line-height:1.35;letter-spacing:-.02em;max-width:26ch}
.hero .kick em{font-style:normal;color:var(--accent)}
.hero .sub{margin-top:16px;font-size:clamp(15px,1.4vw,17px);color:var(--muted);max-width:60ch;line-height:1.65;font-weight:400}
.hero .meta-line{margin-top:clamp(28px,4.8vh,52px);width:100%;display:grid;grid-template-columns:repeat(3,1fr);padding-top:0}
.hero .meta-line > div{padding:0 20px}
.hero .meta-line > div + div{border-left:1px solid var(--line)}
.hero .meta-line dt{font-size:12px;font-weight:400;letter-spacing:.02em;color:var(--muted);margin-bottom:6px}
.hero .meta-line dd{font-size:17px;font-weight:600;color:var(--ink);letter-spacing:-.015em}
@media(max-width:680px){
  .hero .meta-line{grid-template-columns:1fr;gap:14px}
  .hero .meta-line > div{padding:0}
  .hero .meta-line > div + div{border-left:0}
}

/* ============ SECTION SHELL (alternating bands) ============ */
.chap{padding:clamp(140px,19vh,230px) 0}
main > section:nth-child(even){background:var(--seed-surface)}
.shead{display:flex;align-items:center;gap:18px;flex-wrap:wrap}
.snum{font-size:12px;font-weight:600;letter-spacing:.02em;color:var(--accent);
  background:var(--accent-soft);padding:6px 13px;border-radius:var(--r-pill)}
.stitle{font-family:var(--cjk);font-weight:700;font-size:clamp(36px,4.6vw,60px);line-height:1.05;letter-spacing:-.025em}
.skick{font-size:14px;font-weight:400;letter-spacing:-.01em;color:var(--muted);margin-left:auto;white-space:nowrap}
.lead{margin-top:clamp(36px,5vh,60px);font-size:clamp(19px,2.1vw,27px);font-weight:600;line-height:1.35;letter-spacing:-.02em;max-width:26ch;color:var(--ink)}
.lead .accent{font-weight:600}
@media(max-width:640px){.skick{display:none}.shead{gap:12px}}

/* ============ CARDS (shared, band-aware) ============ */
.cell,.fcol,.hcol,.rcol{
  background:var(--card);border:0;border-radius:var(--r-card);
  padding:clamp(28px,3vw,42px);
  transition:transform .5s var(--e-out),background .4s,box-shadow .5s var(--e-out)}
main > section:nth-child(even):not(.outcome) :is(.cell,.fcol,.hcol,.rcol){background:var(--seed-bg)}
.cell:hover,.fcol:hover,.hcol:hover,.rcol:hover{transform:translateY(-3px);box-shadow:var(--shadow)}

/* ============ SPARK (big question + trio) ============ */
.spark-q{margin-top:clamp(56px,8vh,96px);font-family:var(--cjk);font-weight:700;font-size:clamp(26px,3.8vw,46px);line-height:1.22;letter-spacing:-.02em;max-width:22ch}
.spark-q .h{color:var(--accent)}
.trio{margin-top:clamp(60px,8.5vh,104px);display:grid;grid-template-columns:repeat(3,1fr);gap:clamp(18px,2vw,26px)}
.trio dt{font-size:12px;font-weight:600;letter-spacing:.02em;color:var(--muted);margin-bottom:12px}
.trio dd{font-size:clamp(16px,1.7vw,19px);font-weight:600;line-height:1.5;color:var(--ink);letter-spacing:-.015em}
@media(max-width:720px){.trio{grid-template-columns:1fr}}

/* ============ FRAME (formula + equation + chain) ============ */
.formula{margin-top:clamp(56px,8vh,96px);display:grid;grid-template-columns:repeat(4,1fr);gap:clamp(16px,1.8vw,24px)}
.fcol .n{display:inline-flex;font-size:12px;font-weight:600;color:var(--accent);letter-spacing:.02em;margin-bottom:16px}
.fcol h4{font-family:var(--cjk);font-weight:600;font-size:clamp(19px,2vw,23px);margin-bottom:8px;letter-spacing:-.015em}
.fcol p{font-size:15px;line-height:1.65;color:var(--muted);font-weight:400}
@media(max-width:860px){.formula{grid-template-columns:repeat(2,1fr)}}
@media(max-width:480px){.formula{grid-template-columns:1fr}}
.eq{margin-top:clamp(56px,8vh,92px);font-weight:600;font-size:clamp(17px,2vw,26px);line-height:1.4;letter-spacing:-.02em;
  background:var(--card);border-radius:var(--r-card);padding:clamp(26px,3.2vw,40px) clamp(26px,3.6vw,48px)}
main > section:nth-child(even) .eq{background:var(--seed-bg)}
.eq .op{color:var(--muted2);padding:0 .14em}
.eq b{font-weight:700}
.chain-panel{margin-top:clamp(60px,9vh,110px);background:var(--seed-bg);border-radius:calc(var(--r-card) + 6px);
  padding:clamp(36px,4.6vw,60px) clamp(28px,4.2vw,56px);box-shadow:var(--shadow)}
.chain{margin-top:0;display:flex;flex-wrap:wrap;align-items:center;gap:14px 10px}
.chain .node{font-size:clamp(16px,1.9vw,21px);font-weight:500;color:var(--muted);
  padding:13px 26px;border-radius:var(--r-pill);background:color-mix(in srgb,var(--seed-fg) 5%,transparent);
  transition:color .5s,background .5s,box-shadow .5s var(--e-out),transform .5s var(--e-out)}
.chain .node.lit{color:var(--ink);background:color-mix(in srgb,var(--seed-fg) 9%,transparent)}
.chain .node.hot{color:var(--white);background:var(--accent);font-weight:700;transform:scale(1.06);
  box-shadow:0 0 0 6px var(--accent-soft),0 14px 30px -10px color-mix(in srgb,var(--seed-primary) 55%,transparent)}
.chain .sep{font-size:0;width:34px;height:2px;background:var(--line-strong);position:relative;flex:none;padding:0}
.chain .sep::after{content:"";position:absolute;right:0;top:50%;width:7px;height:7px;
  border-top:2px solid var(--line-strong);border-right:2px solid var(--line-strong);transform:translateY(-50%) rotate(45deg)}
@media(max-width:640px){.chain .sep{display:none}}
.chain-panel .chain-note{margin-top:clamp(26px,3.4vh,38px);font-size:clamp(16px,1.8vw,20px);font-weight:500;color:var(--ink);max-width:none;line-height:1.7}
.chain-panel .chain-note b{color:var(--accent);font-weight:700}
.chain-note{margin-top:32px;font-size:clamp(15px,1.55vw,18px);color:var(--muted);max-width:54ch;line-height:1.7;font-weight:400}
.chain-note b{color:var(--ink);font-weight:600}

/* ============ EXPLORE (hypotheses + index list) ============ */
.hi{margin-top:clamp(56px,8vh,96px);display:grid;grid-template-columns:repeat(3,1fr);gap:clamp(18px,2vw,26px)}
.hcol .hn{display:inline-flex;font-size:12px;font-weight:600;color:var(--accent);letter-spacing:.02em;margin-bottom:16px}
.hcol h4{font-family:var(--cjk);font-weight:600;font-size:clamp(19px,2vw,23px);margin-bottom:8px;letter-spacing:-.015em}
.hcol p{font-size:15px;line-height:1.65;color:var(--muted);font-weight:400}
@media(max-width:820px){.hi{grid-template-columns:1fr}}

.idx-h{margin:clamp(76px,10.5vh,132px) 0 14px;display:flex;justify-content:space-between;align-items:baseline;gap:16px}
.idx-h .t{font-size:12px;font-weight:600;letter-spacing:.02em;color:var(--muted)}
.idx-h .c{font-size:12px;font-weight:500;color:var(--muted2)}
.index{list-style:none}
.index li{display:grid;grid-template-columns:44px 1.2fr 2fr auto;align-items:center;gap:18px;
  padding:clamp(22px,2.8vw,30px) 18px;border-bottom:1px solid var(--line);border-radius:0;position:relative;overflow:hidden;
  transition:background .3s,padding-left .3s var(--e-out)}
.index li:first-child{border-top:1px solid var(--line)}
.index li:hover{background:color-mix(in srgb,var(--seed-fg) 3%,transparent);padding-left:24px}
.index .ii{font-size:13px;font-weight:500;color:var(--muted2);font-variant-numeric:tabular-nums;transition:color .3s}
.index .in{font-family:var(--cjk);font-weight:600;font-size:clamp(18px,1.9vw,22px);letter-spacing:-.015em}
.index .idd{font-size:14px;color:var(--muted);font-weight:400}
.index .is{font-size:11px;font-weight:600;letter-spacing:.02em;white-space:nowrap;
  padding:6px 13px;border-radius:var(--r-pill)}
.index .is.go{color:var(--accent);background:var(--accent-soft)}
.index .is.hold{color:var(--muted);background:color-mix(in srgb,var(--seed-fg) 6%,transparent)}
.index li:hover .ii{color:var(--accent)}
.index li::after{content:"";position:absolute;left:0;bottom:-1px;height:2px;width:100%;background:var(--accent);transform:scaleX(0);transform-origin:left;transition:transform .8s var(--e-out)}
.index li.go.viz::after{transform:scaleX(1)}
@media(max-width:760px){
  .index li{grid-template-columns:34px 1fr auto;row-gap:8px}
  .index .idd{grid-column:2 / -1}
}

/* ============ STATS + DISTRIBUTION ============ */
.stats{margin-top:clamp(76px,10.5vh,132px);display:grid;grid-template-columns:repeat(4,1fr);gap:clamp(22px,2.8vw,40px)}
.stat{padding-top:0;position:relative;overflow:hidden}
.stat .num{font-weight:700;font-size:clamp(48px,5.6vw,80px);line-height:1;letter-spacing:-.04em;font-variant-numeric:tabular-nums}
.stat .lab{margin-top:12px;font-size:12px;font-weight:500;letter-spacing:.02em;color:var(--muted)}
.stat::after{content:"";position:absolute;left:0;bottom:-8px;height:3px;width:100%;border-radius:2px;background:var(--accent);transform:scaleX(0);transform-origin:left;transition:transform 1.1s var(--e-out) .12s}
.stat.viz::after{transform:scaleX(1)}
@media(max-width:680px){.stats{grid-template-columns:repeat(2,1fr);gap:32px 24px}}

.dist{margin-top:clamp(56px,8vh,88px)}
.dist-head{display:flex;justify-content:space-between;align-items:baseline;font-size:12px;font-weight:600;letter-spacing:.02em;color:var(--muted);margin-bottom:14px}
.dist-head b{color:var(--ink);font-weight:700}
.dist-bar{display:flex;height:8px;width:100%;background:color-mix(in srgb,var(--seed-fg) 8%,transparent);overflow:hidden;border-radius:var(--r-pill)}
.dist-seg{height:100%;width:0;transition:width 1.2s var(--e-out)}
.dist-seg.go{background:var(--accent)}
.dist-seg.hold{background:var(--muted2)}
.dist.viz .dist-seg.go{width:60%}
.dist.viz .dist-seg.hold{width:40%}
.dist-key{display:flex;gap:26px;margin-top:14px;font-size:13px;color:var(--muted);font-weight:400}
.dist-key span{display:flex;align-items:center;gap:8px}
.dist-key i{width:9px;height:9px;display:inline-block;border-radius:50%}
.dist-key .kgo i{background:var(--accent)}
.dist-key .khold i{background:var(--muted2)}

/* ============ OUTCOME (black band) ============ */
.outcome{background:var(--black);color:var(--dark-fg);overflow:hidden;position:relative}
main > section.outcome{background:var(--black)}
.outcome .wrap{position:relative;z-index:1}
.outcome .snum{color:var(--white);background:color-mix(in srgb,var(--seed-primary) 40%,transparent)}
.outcome .stitle{color:var(--dark-fg)}
.outcome .skick{color:rgba(245,245,247,.5)}
.oq{margin-top:clamp(56px,8vh,96px);font-family:var(--cjk);font-weight:700;font-size:clamp(28px,4vw,50px);line-height:1.18;letter-spacing:-.025em;max-width:19ch}
.oq .h{color:color-mix(in srgb,var(--seed-primary) 62%,var(--white))}
.ofoot{margin-top:clamp(64px,9vh,112px);display:grid;grid-template-columns:repeat(3,1fr);gap:clamp(18px,2vw,26px)}
.ofoot .cell{background:var(--dark-card);border-radius:var(--r-card);padding:clamp(24px,2.6vw,34px)}
.ofoot .cell:hover{background:var(--dark-card-hover);box-shadow:none}
.ofoot dt{font-size:12px;font-weight:500;letter-spacing:.02em;color:rgba(245,245,247,.55);margin-bottom:10px}
.ofoot dd{font-size:clamp(16px,1.7vw,19px);font-weight:600;color:var(--dark-fg);letter-spacing:-.015em}
@media(max-width:720px){.ofoot{grid-template-columns:1fr}}

/* ============ ROADMAP ============ */
.rtrack{position:relative;height:2px;background:color-mix(in srgb,var(--seed-fg) 12%,transparent);margin-top:clamp(56px,8vh,92px)}
.rline{position:absolute;left:0;top:0;height:2px;background:var(--accent);width:0;transition:width 1.3s var(--e-out) .1s}
.rtrack.viz .rline{width:16.67%}
.rdot{position:absolute;top:50%;transform:translate(-50%,-50%);width:12px;height:12px;border-radius:50%;background:var(--paper);border:2px solid var(--muted2);transition:border-color .5s,background .5s,box-shadow .5s}
.rdot.d1{left:16.67%}.rdot.d2{left:50%}.rdot.d3{left:83.33%}
.rdot.done{border-color:var(--accent);background:var(--accent);box-shadow:0 0 0 5px var(--accent-soft)}
@media(max-width:820px){.rtrack{display:none}}
.road{margin-top:clamp(48px,6.5vh,72px);display:grid;grid-template-columns:repeat(3,1fr);gap:clamp(18px,2vw,26px)}
.rcol .rv{font-weight:700;font-size:clamp(30px,3vw,38px);line-height:1;letter-spacing:-.035em}
.rcol .rs{display:inline-flex;font-size:11px;font-weight:600;letter-spacing:.02em;
  margin:14px 0 16px;color:var(--muted);background:color-mix(in srgb,var(--seed-fg) 6%,transparent);padding:6px 12px;border-radius:var(--r-pill)}
.rcol.done .rs{color:var(--accent);background:var(--accent-soft)}
.rcol h4{font-family:var(--cjk);font-weight:600;font-size:clamp(19px,2vw,23px);margin-bottom:8px;letter-spacing:-.015em}
.rcol p{font-size:15px;line-height:1.65;color:var(--muted);font-weight:400}
@media(max-width:820px){.road{grid-template-columns:1fr}}

/* ============ FOOTER ============ */
footer{background:var(--seed-surface);padding:clamp(120px,16vh,200px) 0 clamp(44px,6vh,64px)}
.fbig{font-family:var(--cjk);font-weight:700;font-size:clamp(48px,7.6vw,104px);line-height:1.02;letter-spacing:-.03em;color:var(--ink)}
.fmeta{margin-top:clamp(48px,7vh,80px);display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:14px 32px;
  border-top:1px solid var(--line);padding-top:22px;font-size:12px;font-weight:400;letter-spacing:.01em;color:var(--muted)}
.fmeta .accent{color:var(--accent)}
.totop{display:inline-flex;align-items:center;gap:8px;font-size:12px;font-weight:500;letter-spacing:.01em;color:var(--ink);
  border:1px solid color-mix(in srgb,var(--seed-fg) 24%,transparent);padding:8px 16px;border-radius:var(--r-pill);
  transition:color .25s,border-color .25s,transform .3s var(--e-out)}
.totop:hover{color:var(--accent);border-color:var(--accent);transform:translateY(-2px)}

/* ============ REVEAL ============ */
.reveal{opacity:0;transform:translateY(var(--rise));transition:opacity var(--dur) var(--e-out),transform var(--dur) var(--e-out)}
.reveal.in{opacity:1;transform:none}

/* ============ REDUCED MOTION ============ */
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  .reveal{opacity:1;transform:none;transition:none}
  .reveal.in{transform:none}
  .stat::after,.dist-seg,.rline,.chain .node,.index li::after{transition:none}
  .stat.viz::after{transform:scaleX(1)}
  .dist.viz .dist-seg.go{width:60%}.dist.viz .dist-seg.hold{width:40%}
  .rtrack.viz .rline{width:16.67%}
  .index li{transition:none}
}