:root{
  --bg:#04040c;
  --bg-2:#080a18;
  --surface:rgba(255,255,255,.045);
  --surface-2:rgba(255,255,255,.075);
  --line:rgba(180,200,255,.16);
  --text:#e9ecfa;
  --muted:#9aa3c4;
  --accent:#7ad7ff;
  --accent-2:#c9a3ff;
  --warm:#ffb26b;

  --font-display:'Clash Display','Satoshi',system-ui,sans-serif;
  --font-body:'Satoshi',system-ui,-apple-system,sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,monospace;

  --text-xs:clamp(.72rem,.7rem + .1vw,.8rem);
  --text-sm:clamp(.85rem,.83rem + .12vw,.94rem);
  --text-base:clamp(1rem,.97rem + .18vw,1.1rem);
  --text-lg:clamp(1.15rem,1.05rem + .5vw,1.4rem);
  --text-xl:clamp(1.55rem,1.2rem + 1.6vw,2.2rem);
  --text-2xl:clamp(2.1rem,1.4rem + 3.2vw,3.4rem);
  --text-hero:clamp(2.6rem,1.4rem + 6.2vw,6rem);

  --space-2:.5rem; --space-3:.75rem; --space-4:1rem; --space-6:1.5rem;
  --space-8:2rem; --space-12:3rem; --space-16:4rem; --space-24:6rem;
  --radius:18px;
  --ease:cubic-bezier(.16,1,.3,1);
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
[id]{scroll-margin-top:96px}
body{
  margin:0;background:var(--bg);color:var(--text);
  font-family:var(--font-body);font-size:var(--text-base);line-height:1.65;
  -webkit-font-smoothing:antialiased;overflow-x:hidden;
}
h1,h2,h3{font-family:var(--font-display);font-weight:600;line-height:1.02;letter-spacing:-.02em;margin:0}
h2{font-size:var(--text-2xl)}
h3{font-size:var(--text-xl)}
p{margin:0}
a{color:inherit}
img{max-width:100%;display:block}
::selection{background:var(--accent);color:#02040c}

#stars{position:fixed;inset:0;width:100%;height:100%;z-index:0;pointer-events:none}
main,.nav,.footer{position:relative;z-index:2}

/* ---------- NAV ---------- */
.nav{
  position:sticky;top:0;display:flex;align-items:center;gap:var(--space-6);
  padding:var(--space-4) clamp(1rem,4vw,3rem);
  background:rgba(4,4,12,.55);backdrop-filter:blur(14px);
  border-bottom:1px solid transparent;transition:border-color .3s var(--ease),background .3s var(--ease);
}
.nav.is-scrolled{border-bottom-color:var(--line);background:rgba(4,4,12,.82)}
.brand{display:flex;align-items:center;gap:.6rem;text-decoration:none;color:var(--accent)}
.brand__mark{width:30px;height:30px;flex:none;animation:tilt 14s ease-in-out infinite}
@keyframes tilt{0%,100%{transform:rotate(0)}50%{transform:rotate(8deg)}}
.brand__word{font-family:var(--font-display);font-size:1.05rem;letter-spacing:.28em;color:var(--text)}
.nav__links{margin-left:auto;display:flex;gap:clamp(.9rem,2vw,1.8rem);font-size:var(--text-sm)}
.nav__links a{position:relative;text-decoration:none;color:var(--muted);padding:.2rem 0;transition:color .25s}
.nav__links a::after{content:"";position:absolute;left:0;bottom:0;height:1px;width:0;background:var(--accent);transition:width .3s var(--ease)}
.nav__links a:hover{color:var(--text)}
.nav__links a:hover::after{width:100%}
.nav__cta{margin-left:.5rem}
@media(max-width:760px){.nav__links{display:none}.nav__cta{margin-left:auto}}

.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5rem;
  font-size:var(--text-sm);font-weight:500;text-decoration:none;cursor:pointer;
  padding:.7rem 1.3rem;border-radius:999px;border:1px solid var(--line);
  background:transparent;color:var(--text);
  transition:transform .25s var(--ease),background .25s,border-color .25s,box-shadow .25s;
}
.btn:hover{transform:translateY(-2px);border-color:var(--accent);box-shadow:0 8px 30px rgba(122,215,255,.18)}
.btn--primary{background:linear-gradient(120deg,var(--accent),var(--accent-2));color:#04040c;border-color:transparent;font-weight:700}
.btn--primary:hover{box-shadow:0 10px 40px rgba(201,163,255,.35)}

/* ---------- HERO ---------- */
.hero{position:relative;min-height:100svh;display:grid;place-items:center;padding:var(--space-24) clamp(1rem,5vw,3rem) var(--space-16);overflow:hidden}
.hero__bg{
  position:absolute;inset:-10% -5% 0;background:url('assets/nebula-hero.png') center/cover no-repeat;
  opacity:.5;filter:saturate(1.05);
  mask-image:radial-gradient(120% 80% at 50% 30%,#000 25%,transparent 78%);
  -webkit-mask-image:radial-gradient(120% 80% at 50% 30%,#000 25%,transparent 78%);
  will-change:transform;
}
.hero__glow{position:absolute;left:50%;top:12%;width:min(90vw,900px);aspect-ratio:1;transform:translateX(-50%);
  background:radial-gradient(circle,rgba(122,215,255,.16),transparent 62%);animation:breathe 9s ease-in-out infinite}
@keyframes breathe{0%,100%{opacity:.55;transform:translateX(-50%) scale(1)}50%{opacity:1;transform:translateX(-50%) scale(1.12)}}
.hero__inner{position:relative;max-width:min(1100px,100%);text-align:center;display:grid;gap:var(--space-6);justify-items:center}
.eyebrow{font-family:var(--font-mono);font-size:var(--text-xs);letter-spacing:.32em;text-transform:uppercase;color:var(--accent)}
.hero__title{font-size:var(--text-hero);max-width:18ch;text-wrap:balance}
.hero__title .line{display:block}
.hero__title .line--accent span{background:linear-gradient(100deg,var(--accent),var(--accent-2) 60%,var(--warm));-webkit-background-clip:text;background-clip:text;color:transparent}
.hero__title span span{display:inline-block;opacity:0;transform:translateY(.5em);animation:word .9s var(--ease) forwards}
.hero__lede{max-width:58ch;color:var(--muted)}
.hero__actions{display:flex;gap:var(--space-3);flex-wrap:wrap;justify-content:center}
.hero__stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(45%,130px),1fr));gap:var(--space-6);margin:var(--space-8) 0 0;width:min(720px,100%);border-top:1px solid var(--line);padding-top:var(--space-6)}
.hero__stats dt{font-size:var(--text-xs);color:var(--muted);letter-spacing:.08em}
.hero__stats dd{margin:.25rem 0 0;font-family:var(--font-display);font-size:var(--text-xl);color:var(--text)}
@keyframes word{to{opacity:1;transform:none}}
.scroll-cue{position:absolute;bottom:var(--space-8);left:50%;transform:translateX(-50%);font-family:var(--font-mono);font-size:var(--text-xs);letter-spacing:.28em;text-transform:uppercase;color:var(--muted);display:grid;justify-items:center;gap:.6rem}
.scroll-cue span{width:1px;height:44px;background:linear-gradient(var(--accent),transparent);animation:drop 2.2s ease-in-out infinite}
@keyframes drop{0%,100%{opacity:.25;transform:scaleY(.5)}50%{opacity:1;transform:scaleY(1)}}

/* ---------- SECTIONS ---------- */
.section{padding:clamp(4rem,9vw,8rem) clamp(1rem,5vw,3rem);max-width:1200px;margin-inline:auto}
.section--band{background:linear-gradient(180deg,transparent,rgba(10,14,32,.85) 20%,rgba(10,14,32,.85) 80%,transparent);max-width:none}
.section--band > *{max-width:1200px;margin-inline:auto}
.section__head{display:grid;gap:var(--space-4);max-width:62ch;margin-bottom:var(--space-12)}
.section__lede{color:var(--muted)}

.reveal{opacity:1}
@supports (animation-timeline:view()){
  .reveal{opacity:0;animation:fadeIn linear both;animation-timeline:view();animation-range:entry 5% entry 60%}
}
@keyframes fadeIn{to{opacity:1}}
@media(prefers-reduced-motion:reduce){
  .reveal{opacity:1;animation:none}
  *{animation-duration:.001s!important;animation-iteration-count:1!important}
}

/* ---------- SOLAR SYSTEM ---------- */
.solar-wrap{display:grid;gap:var(--space-6);justify-items:center}
.solar{
  position:relative;width:min(92vw,680px);aspect-ratio:1;display:grid;place-items:center;
  --paused:running;
}
.orbit{position:absolute;top:50%;left:50%;border-radius:50%;border:1px solid var(--line);
  transform:translate(-50%,-50%);animation:spin linear infinite;animation-play-state:var(--paused);}
.solar.no-orbits .orbit{border-color:transparent}
@keyframes spin{to{transform:translate(-50%,-50%) rotate(360deg)}}
.planet{
  position:absolute;top:0;left:50%;translate:-50% -50%;border-radius:50%;cursor:pointer;
  border:0;padding:0;box-shadow:0 0 12px rgba(0,0,0,.6);
  transition:transform .3s var(--ease),box-shadow .3s var(--ease);
}
.planet:hover,.planet:focus-visible{transform:translate(-50%,-50%) scale(1.45);outline:none;box-shadow:0 0 0 2px var(--accent),0 0 22px rgba(122,215,255,.6)}
.planet.is-active{box-shadow:0 0 0 2px var(--accent-2),0 0 26px rgba(201,163,255,.7)}
.planet__ring{position:absolute;inset:-42% -78%;border-radius:50%;border:2px solid rgba(255,225,180,.55);transform:rotate(-18deg)}
.planet__label{
  position:absolute;left:50%;top:150%;translate:-50% 0;font-family:var(--font-mono);font-size:10px;
  letter-spacing:.12em;text-transform:uppercase;color:var(--text);white-space:nowrap;opacity:0;
  transition:opacity .25s;text-shadow:0 0 8px #04040c,0 0 14px #04040c;
  animation:spin-back linear infinite;animation-play-state:var(--paused);animation-direction:reverse;
}
@keyframes spin-back{to{rotate:360deg}}
.planet:hover .planet__label,.planet.is-active .planet__label{opacity:1}
.sun{
  position:relative;width:clamp(46px,8vw,64px);aspect-ratio:1;border-radius:50%;cursor:pointer;border:0;padding:0;
  background:radial-gradient(circle at 40% 40%,#fff6d8,#ffcf5c 45%,#ff8a2b 80%);
  box-shadow:0 0 40px rgba(255,170,60,.55),0 0 110px rgba(255,120,40,.28);
  animation:pulse 5s ease-in-out infinite;z-index:3
}
.sun__core{position:absolute;inset:-40%;border-radius:50%;background:radial-gradient(circle,rgba(255,180,80,.28),transparent 65%)}
@keyframes pulse{0%,100%{box-shadow:0 0 34px rgba(255,170,60,.45),0 0 90px rgba(255,120,40,.2)}50%{box-shadow:0 0 54px rgba(255,190,90,.7),0 0 140px rgba(255,120,40,.35)}}

.solar-controls{display:flex;align-items:center;gap:var(--space-4);flex-wrap:wrap;justify-content:center}
.chip{font-family:var(--font-mono);font-size:var(--text-xs);letter-spacing:.14em;text-transform:uppercase;
  padding:.45rem .9rem;border-radius:999px;border:1px solid var(--line);background:transparent;color:var(--muted);cursor:pointer;transition:.25s}
.chip--on{color:#04040c;background:var(--accent);border-color:var(--accent)}
.speed{display:flex;align-items:center;gap:.6rem;font-family:var(--font-mono);font-size:var(--text-xs);letter-spacing:.14em;text-transform:uppercase;color:var(--muted)}

input[type=range]{-webkit-appearance:none;appearance:none;height:3px;border-radius:99px;background:linear-gradient(90deg,var(--accent),var(--accent-2));width:min(260px,60vw)}
input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:18px;height:18px;border-radius:50%;background:#fff;border:3px solid var(--accent);cursor:pointer;box-shadow:0 0 14px rgba(122,215,255,.7)}
input[type=range]::-moz-range-thumb{width:16px;height:16px;border-radius:50%;background:#fff;border:3px solid var(--accent);cursor:pointer}

/* planet card */
.planet-card{
  margin-top:var(--space-16);display:grid;grid-template-columns:minmax(180px,.5fr) 1.5fr;gap:clamp(1.5rem,4vw,3rem);
  align-items:center;padding:clamp(1.4rem,3vw,2.5rem);border:1px solid var(--line);border-radius:calc(var(--radius) + 6px);
  background:linear-gradient(140deg,var(--surface),rgba(255,255,255,.015));backdrop-filter:blur(8px);
}
.planet-card__visual{display:grid;place-items:center}
.planet-card__globe{width:min(58vw,190px);aspect-ratio:1;border-radius:50%;position:relative;animation:float 7s ease-in-out infinite}
.planet-card__globe::after{content:"";position:absolute;inset:0;border-radius:50%;box-shadow:inset -18px -12px 40px rgba(0,0,0,.65)}
@keyframes float{0%,100%{transform:translateY(-6px)}50%{transform:translateY(8px)}}
.planet-card__index{font-family:var(--font-mono);font-size:var(--text-xs);letter-spacing:.2em;text-transform:uppercase;color:var(--accent)}
.planet-card h3{margin:.3rem 0 .6rem}
.planet-card__body > p{color:var(--muted);max-width:60ch}
.planet-card__nav{display:flex;gap:var(--space-3);margin-top:var(--space-6)}
.specs{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,175px),1fr));gap:var(--space-4);margin:var(--space-6) 0 0}
.specs dt{font-size:var(--text-xs);letter-spacing:.1em;text-transform:uppercase;color:var(--muted)}
.specs dd{margin:.2rem 0 0;font-family:var(--font-mono);font-size:var(--text-sm);color:var(--text)}
@media(max-width:720px){.planet-card{grid-template-columns:1fr;text-align:center}.planet-card__body > p{margin-inline:auto}.planet-card__nav,.specs{justify-content:center}}

/* ---------- SCALE ---------- */
.scale{display:grid;gap:var(--space-8);justify-items:center}
.scale__track{position:relative;width:100%;height:170px;border-radius:var(--radius);overflow:hidden;
  background:radial-gradient(circle at 0% 50%,rgba(255,180,80,.35),transparent 30%),rgba(255,255,255,.03);border:1px solid var(--line)}
.scale__dot{position:absolute;top:50%;translate:-50% -50%;border-radius:50%;transition:opacity .3s}
.scale__dot span{position:absolute;left:50%;top:calc(150% + var(--off,0px));translate:-50% 0;font-family:var(--font-mono);font-size:10px;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);white-space:nowrap}
.scale__marker{position:absolute;top:0;bottom:0;width:2px;background:linear-gradient(var(--accent),transparent);box-shadow:0 0 16px var(--accent);transition:left .12s linear}
@media(max-width:760px){
  .scale__dot span{writing-mode:vertical-rl;text-orientation:mixed;top:calc(120% + 0px)!important;letter-spacing:.06em}
  .scale__track{height:210px}
}
.scale__readout{display:grid;grid-template-columns:repeat(auto-fit,minmax(140px,1fr));gap:var(--space-6);width:100%;text-align:center}
.scale__readout .big{display:block;font-family:var(--font-display);font-size:var(--text-xl);color:var(--accent)}
.scale__readout small{color:var(--muted);font-size:var(--text-xs);letter-spacing:.12em;text-transform:uppercase}

/* ---------- STAR LAB ---------- */
.star-lab{display:grid;grid-template-columns:1fr 1fr;gap:clamp(1.5rem,4vw,3rem);align-items:center;
  padding:clamp(1.4rem,3vw,2.5rem);border:1px solid var(--line);border-radius:calc(var(--radius) + 6px);background:linear-gradient(140deg,var(--surface),rgba(255,255,255,.015))}
.star-lab__stage{display:grid;place-items:center;min-height:260px}
.star-orb{position:relative;width:min(46vw,180px);aspect-ratio:1;border-radius:50%;transition:background .4s,box-shadow .4s;animation:pulse-star 4s ease-in-out infinite}
.star-orb__flare{position:absolute;inset:-45%;border-radius:50%;background:radial-gradient(circle,rgba(255,255,255,.16),transparent 62%);animation:breathe 6s ease-in-out infinite}
@keyframes pulse-star{0%,100%{transform:scale(1)}50%{transform:scale(1.05)}}
.field{display:grid;gap:.6rem;font-size:var(--text-xs);letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}
.field input[type=number]{font-family:var(--font-mono);font-size:var(--text-lg);color:var(--text);background:rgba(255,255,255,.05);
  border:1px solid var(--line);border-radius:12px;padding:.7rem .9rem;width:100%;text-transform:none;letter-spacing:0}
.field input[type=number]:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(122,215,255,.16)}
.star-lab__temp{font-family:var(--font-display);font-size:var(--text-2xl);margin-top:var(--space-4)}
.star-lab__temp small{font-family:var(--font-mono);font-size:var(--text-sm);color:var(--muted)}
@media(max-width:760px){.star-lab{grid-template-columns:1fr}}

/* ---------- TIMELINE ---------- */
.lifecycle{margin-top:var(--space-24)}
.timeline::-webkit-scrollbar{height:6px}
.timeline::-webkit-scrollbar-thumb{background:rgba(122,215,255,.4);border-radius:99px}
.timeline::-webkit-scrollbar-track{background:rgba(255,255,255,.05);border-radius:99px}
.timeline{list-style:none;margin:var(--space-8) 0 0;padding:0 0 var(--space-6);display:flex;gap:var(--space-4);overflow-x:auto;scroll-snap-type:x mandatory}
.timeline li{scroll-snap-align:center;flex:0 0 clamp(230px,72vw,300px);padding:var(--space-6);border:1px solid var(--line);border-radius:var(--radius);
  background:linear-gradient(160deg,var(--surface),transparent);transition:transform .3s var(--ease),border-color .3s}
.timeline li:hover{transform:translateY(-6px);border-color:var(--accent)}
.timeline .step{font-family:var(--font-mono);font-size:var(--text-xs);color:var(--accent);letter-spacing:.2em}
.timeline h4{font-family:var(--font-display);font-size:var(--text-lg);margin:.5rem 0 .5rem;font-weight:500}
.timeline p{color:var(--muted);font-size:var(--text-sm)}
.timeline .dot{width:14px;height:14px;border-radius:50%;margin-bottom:var(--space-4);box-shadow:0 0 18px currentColor}

/* ---------- LAB ---------- */
.lab{display:grid;gap:var(--space-8)}
.lab__inputs{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,170px),1fr));gap:var(--space-6);max-width:560px}
.lab__grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,158px),1fr));gap:var(--space-4)}
.lab-card{padding:var(--space-4) var(--space-4) var(--space-6);border:1px solid var(--line);border-radius:var(--radius);background:linear-gradient(160deg,var(--surface),transparent);
  display:grid;gap:.35rem;transition:transform .3s var(--ease),border-color .3s}
.lab-card:hover{transform:translateY(-5px);border-color:var(--accent-2)}
.lab-card__dot{width:26px;height:26px;border-radius:50%;margin-bottom:var(--space-2)}
.lab-card h4{font-family:var(--font-display);font-weight:500;font-size:var(--text-lg);margin:0}
.lab-card .kg{font-family:var(--font-mono);font-size:var(--text-lg);color:var(--accent)}
.lab-card .yr{font-family:var(--font-mono);font-size:var(--text-sm);color:var(--muted)}

/* ---------- CLOSING / FOOTER ---------- */
.closing{padding:clamp(5rem,12vw,10rem) clamp(1rem,5vw,3rem);text-align:center}
.closing blockquote{margin:0 auto;max-width:min(880px,92vw)}
.closing p{font-family:var(--font-display);font-size:var(--text-2xl);line-height:1.12;max-width:26ch;margin-inline:auto;text-wrap:balance;
  background:linear-gradient(100deg,var(--accent),var(--accent-2));-webkit-background-clip:text;background-clip:text;color:transparent}
.closing cite{display:block;margin-top:var(--space-6);font-style:normal;font-family:var(--font-mono);font-size:var(--text-xs);letter-spacing:.24em;text-transform:uppercase;color:var(--muted)}
.footer{border-top:1px solid var(--line);padding:var(--space-12) clamp(1rem,5vw,3rem);display:grid;gap:var(--space-4);max-width:1200px;margin-inline:auto}
.footer__brand{display:flex;align-items:center;gap:.6rem;color:var(--accent)}
.footer__brand .brand__mark{width:26px;height:26px}
.footer__note{font-size:var(--text-sm);color:var(--muted);max-width:80ch}
.footer__note a{color:var(--accent);text-decoration:none;border-bottom:1px solid transparent;transition:border-color .2s}
.footer__note a:hover{border-bottom-color:var(--accent)}
.footer__meta{font-family:var(--font-mono);font-size:var(--text-xs);color:rgba(154,163,196,.7);letter-spacing:.1em}
:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:6px}