:root{--bg:#0b0820;--ink:#ece8ff;--mut:#a39fc8;--a:#38e8c6;--b:#7b6cff;--c:#ff4d6d;--card:rgba(24,18,60,.72)}
*{box-sizing:border-box}html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.6 "Instrument Sans",system-ui,sans-serif;overflow-x:hidden}
.mono{font-family:"Jetbrains Mono",monospace}.small{font-size:13px;color:var(--mut)}
h1,h2,h3{font-family:"Syne",sans-serif;font-weight:800;letter-spacing:-.01em;line-height:1.05}
a{color:var(--a)}
.aurora{position:fixed;inset:0;z-index:-1;background:radial-gradient(40% 50% at 20% 20%,#3b1f8a 0,transparent 70%),radial-gradient(35% 45% at 80% 30%,#0e6b6b 0,transparent 70%),radial-gradient(50% 40% at 50% 90%,#6a1240 0,transparent 70%),var(--bg);background-size:140% 140%;animation:aur 20s ease-in-out infinite alternate}
@keyframes aur{0%{background-position:0% 0%}50%{background-position:60% 40%}100%{background-position:100% 100%}}
.hero .in{max-width:1100px;margin:auto;padding:60px 20px 30px;display:grid;grid-template-columns:1.1fr 1fr;gap:30px;align-items:center}
.tag{font:600 13px "Jetbrains Mono";text-transform:uppercase;letter-spacing:.12em;color:var(--a)}
h1{font-size:clamp(40px,7vw,78px);margin:.2em 0}
h1 em{font-style:normal;background:linear-gradient(90deg,#ff4d6d,#ffd166,#38e8c6,#7b6cff,#ff4d6d);background-size:300% 100%;-webkit-background-clip:text;background-clip:text;color:transparent;animation:flow 6s linear infinite}
@keyframes flow{to{background-position:300% 0}}
.lede{color:#d4cff5;max-width:520px}
.cap{font-size:12px;color:var(--mut);margin-top:6px}
.atom3d{aspect-ratio:1;width:100%;max-width:460px;justify-self:center;opacity:0;transform:translateY(40px) scale(.8);transition:opacity 1.2s,transform 1.4s cubic-bezier(.2,.8,.2,1);cursor:grab;filter:drop-shadow(0 0 40px rgba(123,108,255,.35))}
.atom3d.live{opacity:1;transform:none}.atom3d canvas{width:100%!important;height:100%!important;display:block}
.barcode{position:relative;height:56px;background:#000;border-radius:6px;overflow:hidden;box-shadow:inset 0 0 0 1px #2a2560}
.barcode.big{height:80px;max-width:520px}.barcode.sm{height:28px}
.barcode i{position:absolute;top:0;bottom:0;width:4px;margin-left:-2px;background:var(--c);box-shadow:0 0 10px var(--c),0 0 22px var(--c)}
.barcode i.pop{animation:pop .7s cubic-bezier(.2,.8,.2,1.4)}
@keyframes pop{from{transform:scaleY(0);opacity:0}}
main{max-width:1100px;margin:auto;padding:0 20px}
.story{display:grid;grid-template-columns:1fr 1fr;gap:40px;margin:40px 0}
.stage{position:relative}.stagebox{position:sticky;top:90px;background:var(--card);border:1px solid #2f2873;border-radius:20px;padding:18px;backdrop-filter:blur(8px)}
#lvl{width:100%;height:auto}
#lvl .lv{stroke:#8a85c9;stroke-width:2}#lvl .lv.thin{stroke-width:1;opacity:.5}#lvl .lim{stroke:#ff4d6d;stroke-dasharray:5 5}
#lvl .lt{fill:#a39fc8;font:12px "Jetbrains Mono"}
#lvl #el{fill:var(--a);filter:drop-shadow(0 0 6px #38e8c6);transition:cy .8s cubic-bezier(.5,-0.3,.4,1.4)}
#lvl .arr{stroke-width:3;fill:none;stroke-dasharray:6 4;animation:dash 1s linear infinite}
@keyframes dash{to{stroke-dashoffset:-20}}
#lvl .wv{stroke-dasharray:400;stroke-dashoffset:400;animation:draw 1.2s forwards}#lvl .dropl{animation:pop .6s both}
@keyframes draw{to{stroke-dashoffset:0}}
.step{min-height:70vh;display:flex;flex-direction:column;justify-content:center;opacity:.28;transition:opacity .5s,transform .5s;transform:translateX(20px)}
.step.act{opacity:1;transform:none}
.step .n{font:800 60px "Syne";color:transparent;-webkit-text-stroke:1.5px var(--a);line-height:1}
.step h2{font-size:32px;margin:6px 0}
.panel{background:var(--card);border:1px solid #2f2873;border-radius:24px;padding:26px;margin:40px 0;backdrop-filter:blur(8px)}
.head{display:flex;gap:12px;align-items:center;flex-wrap:wrap}.head h2{margin:0;font-size:clamp(26px,4vw,38px)}
.chip{font:700 12px "Jetbrains Mono";padding:4px 10px;border-radius:99px;background:linear-gradient(90deg,var(--c),var(--b));text-transform:uppercase}
html.js [data-reveal]{opacity:0;transform:perspective(900px) rotateX(14deg) translateY(60px);transition:opacity .9s,transform 1s cubic-bezier(.2,.8,.2,1)}
html.js [data-reveal].in{opacity:1;transform:none}
button{font:600 15px "Instrument Sans";color:var(--ink);background:#1d1650;border:1px solid #3d3590;border-radius:12px;padding:9px 14px;cursor:pointer;transition:transform .15s,background .2s}
button:hover{transform:translateY(-2px);background:#2a2170}button.on{background:var(--b);border-color:#a99fff}
button.go{background:linear-gradient(90deg,var(--c),var(--b));border:0;font-size:17px;padding:12px 22px}
button.ghost{background:transparent}
.note{font-family:"Jetbrains Mono";font-size:14px;color:#ffd166;min-height:1.6em}
.jumplab{display:grid;grid-template-columns:200px 1fr;gap:24px;margin-top:16px}
.ladder{display:flex;flex-direction:column;gap:6px}
.rung{text-align:left;font-family:"Jetbrains Mono";padding:calc(4px + var(--h)*2px) 12px;border-radius:8px}
.ctrlrow{display:flex;gap:6px;align-items:center;flex-wrap:wrap;margin-bottom:12px}
.jumpout>*{margin-bottom:12px}
.wipe{--w:50%;position:relative;height:110px;border-radius:12px;overflow:hidden;margin:18px 0}
.wipe .cont{position:absolute;inset:0;background:linear-gradient(90deg,#6a00a8,#2b3cff,#00c4ff,#00e676,#ffe600,#ff8a00,#ff1f1f,#6d0000)}
.wipe .lines{position:absolute;inset:0;height:auto;border-radius:0;clip-path:inset(0 0 0 var(--w))}
.wipe input{position:absolute;inset:0;width:100%;height:100%;opacity:0;cursor:ew-resize;margin:0}
.wipe::after{content:"";position:absolute;top:0;bottom:0;left:var(--w);width:3px;background:#fff;box-shadow:0 0 12px #fff;pointer-events:none}
.tri{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;font-size:14px}.tri div{background:#140f3a;border-radius:12px;padding:12px}
.bench{display:grid;grid-template-columns:160px 1fr;gap:24px;align-items:end;margin:18px 0}
.burner{position:relative;height:220px;display:flex;flex-direction:column;align-items:center;justify-content:flex-end}
.tube{width:30px;height:70px;background:linear-gradient(90deg,#555,#bbb,#555);border-radius:4px 4px 0 0}
.flame{--fc:#4d8bff;position:relative;width:70px;height:130px}
.flame i{position:absolute;left:50%;bottom:0;border-radius:50% 50% 45% 45%/70% 70% 30% 30%;transform:translateX(-50%);animation:flick .15s ease-in-out infinite alternate}
.flame i:first-child{width:70px;height:130px;background:radial-gradient(ellipse at 50% 80%,var(--fc),transparent 70%);filter:blur(4px);transition:background .4s}
.flame i:last-child{width:26px;height:50px;background:radial-gradient(ellipse at 50% 80%,#9cc4ff,#3355ff 70%,transparent 72%)}
.flame.lit i:first-child{animation:flick .15s ease-in-out infinite alternate,flare .8s}
@keyframes flick{to{transform:translateX(-50%) scaleY(1.06) skewX(2deg)}}
@keyframes flare{0%{filter:blur(4px) brightness(2.5)}}
.samples{display:grid;grid-template-columns:repeat(auto-fill,minmax(110px,1fr));gap:10px}
.salt{display:flex;flex-direction:column;align-items:flex-start;border-left:4px solid var(--c)}
.salt b{font:800 22px "Syne"}.salt span{font-size:13px;color:var(--mut)}
.ref{display:grid;grid-template-columns:24px 40px 1fr;gap:8px;align-items:center;margin:8px 0;cursor:pointer}
.ref input{width:20px;height:20px;accent-color:var(--a)}
.uses{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;margin-top:14px}
.use{border-radius:18px;padding:16px;background-size:200% 200%;animation:aur 10s ease-in-out infinite alternate}
.use h3{margin:0 0 6px;font-size:22px}.use p{margin:0;font-size:15px}
.u1{background-image:linear-gradient(135deg,#5a0e2a,#a3203f,#3b0a52)}.u2{background-image:linear-gradient(135deg,#5b3a00,#a86300,#3b1d00)}
.u3{background-image:linear-gradient(135deg,#0c2a5b,#1b5fa8,#0d3b3b)}.u4{background-image:linear-gradient(135deg,#5b1d00,#c2410c,#5b0030)}
.recap ol{font-size:18px}.recap li{margin:6px 0}
.foot{text-align:center;color:var(--mut);font-size:12px;padding:40px}
@media(max-width:800px){.hero .in{grid-template-columns:1fr;padding-top:30px}.atom3d{max-width:300px;order:-1}
.story{grid-template-columns:1fr;gap:0}.stage{position:sticky;top:64px;z-index:2}.stagebox{position:static;padding:10px}#lvl{max-height:34vh}
.step{min-height:60vh;background:linear-gradient(transparent,rgba(11,8,32,.9) 30%);padding:10px 0}.step h2{font-size:26px}
.jumplab,.bench{grid-template-columns:1fr}.ladder{flex-direction:row;flex-wrap:wrap}.rung{padding:8px 12px}.tri{grid-template-columns:1fr}.panel{padding:18px}.burner{height:180px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important}html{scroll-behavior:auto}}
/* fix: scroll-story visual must never cover the text */
.story{position:relative;isolation:isolate}
.stagebox{top:84px;max-height:calc(100vh - 110px);max-height:calc(100dvh - 110px);display:flex;flex-direction:column;-webkit-position:sticky}
#lvl{flex:1;min-height:0;max-height:calc(100dvh - 170px)}
@media(max-width:800px){
 .stage{position:-webkit-sticky;position:sticky;top:66px;z-index:3;margin:0 -20px;padding:6px 12px;background:rgba(11,8,32,.96);border-bottom:1px solid #2f2873}
 .stagebox{position:static;display:flex;flex-direction:row;align-items:center;gap:10px;max-height:none;padding:6px 10px;border-radius:14px;backdrop-filter:none}
 #lvl{flex:0 0 auto;width:auto;height:21vh;height:21svh;max-height:170px;min-height:120px}
 #stageCap{flex:1;margin:0;font-size:12px}
 .step{position:relative;z-index:1;min-height:auto;padding:28vh 0 28vh;padding:28svh 0;transform:none;background:none}
 .step:first-child{padding-top:24px}
}
/* v3: mobile story = cards with their own mini diagram, no pinned stage */
.mini{display:none}
@media(max-width:800px){
 .stage{display:none}
 .steps{display:flex;flex-direction:column;gap:22px;padding:8px 0 30px}
 .step,.step:first-child{min-height:0;padding:20px 18px 16px;border-radius:20px;opacity:0;transform:translateY(26px);transition:opacity .7s,transform .8s cubic-bezier(.2,.8,.2,1);
  border:1.5px solid transparent;background:linear-gradient(160deg,rgba(28,20,70,.95),rgba(14,10,40,.95)) padding-box,linear-gradient(135deg,var(--acc),rgba(123,108,255,.35) 45%,#ff4d6d 75%,var(--acc)) border-box;
  box-shadow:0 0 24px -6px var(--acc),0 10px 30px -12px #000}
 .step.in{opacity:1;transform:none}
 .step .n{font-size:44px;-webkit-text-stroke-color:var(--acc)}
 .step h2{font-size:24px}
 .mini{display:block;margin:14px 0 0;padding:10px 10px 8px;border-radius:14px;background:rgba(5,3,20,.6);border:1px solid rgba(255,255,255,.07)}
 .mini svg{display:block;width:100%;height:auto}
 .mini figcaption{font:500 12px "Jetbrains Mono",monospace;color:var(--acc);margin-top:6px}
 .mlv{stroke:#4a4390;stroke-width:1.5}.mlv.thin{stroke-width:.8;opacity:.7}.mlim{stroke-width:1.5;stroke-dasharray:4 4;opacity:.8}
 .mlt{fill:#a39fc8;font:9px "Jetbrains Mono",monospace}
 .mel{fill:var(--acc);filter:drop-shadow(0 0 5px var(--acc))}
 .marr{stroke:var(--acc);stroke-width:2;stroke-dasharray:1;stroke-dashoffset:1;opacity:.8}
 .mwv{fill:none;stroke-width:2.5;stroke-dasharray:1;stroke-dashoffset:1;filter:drop-shadow(0 0 4px currentColor)}
 .mdrop{stroke-width:4;stroke-linecap:round;stroke-dasharray:1;stroke-dashoffset:1}
 .step.in .mel{animation:mel 1s .3s cubic-bezier(.5,-.3,.4,1.4) backwards}
 .step.in .marr{animation:mdraw .7s .2s forwards}
 .step.in .mwv{animation:mdraw 1.2s 1s ease-out forwards}
 .step.in .mdrop{animation:mdraw .6s ease-out forwards}
 .step.in .mlv.thin{animation:mfade .6s backwards}
}
@keyframes mel{from{transform:translateY(var(--d))}}
@keyframes mdraw{to{stroke-dashoffset:0}}
@keyframes mfade{from{opacity:0}}
@media(max-width:800px) and (prefers-reduced-motion:reduce){.step,.step:first-child{opacity:1;transform:none}.marr,.mwv,.mdrop{stroke-dashoffset:0}}