/* Cosmos Atlas — landing page */
*{box-sizing:border-box;margin:0;padding:0}
:root{
  --ink:#e8f3fb; --dim:#a9c3d6; --faint:#71889c; --accent:#7fd8ff; --warm:#ffd27f;
  --font:system-ui,-apple-system,'Segoe UI',Roboto,sans-serif;
}
html{scroll-behavior:smooth}
body{background:#04070f;color:var(--ink);font:16px/1.6 var(--font);overflow-x:hidden}
a{color:var(--accent)}

/* ---------- fixed backdrops (crossfaded by scroll) ---------- */
.bg{position:fixed;inset:0;z-index:-3;opacity:0;transition:opacity .28s linear;pointer-events:none}
#bg-solar   {opacity:1;background:radial-gradient(1300px 900px at 72% 8%,#0d2136 0%,#04070f 58%),radial-gradient(700px 500px at 12% 88%,#0a1a2c 0%,transparent 60%)}
#bg-stellar {background:radial-gradient(1200px 850px at 28% 15%,#131b3c 0%,#04060f 60%),radial-gradient(800px 600px at 85% 80%,#0d1230 0%,transparent 65%)}
#bg-galaxy  {background:radial-gradient(1300px 900px at 60% 30%,#231334 0%,#05060e 62%),radial-gradient(700px 500px at 15% 75%,#1a0f2a 0%,transparent 60%)}
#bg-universe{background:radial-gradient(1400px 950px at 50% 40%,#0a0a16 0%,#020308 65%)}
#bg-exo     {background:radial-gradient(1200px 850px at 70% 75%,#0a2426 0%,#04070f 60%),radial-gradient(700px 500px at 20% 20%,#0c1e2e 0%,transparent 60%)}
#stars{position:fixed;inset:0;z-index:-2;pointer-events:none}

/* ---------- top bar ---------- */
#topbar{position:fixed;top:0;left:0;right:0;z-index:50;display:flex;align-items:center;justify-content:space-between;
  padding:14px 26px;transform:translateY(-110%);transition:transform .35s ease,background .35s;}
#topbar.on{transform:none;background:rgba(4,9,18,.72);backdrop-filter:blur(10px);border-bottom:1px solid rgba(127,216,255,.12)}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:700;letter-spacing:.28em;font-size:13px}
.enter-mini{text-decoration:none;font-weight:700;font-size:13px;letter-spacing:.06em;color:#04121f;background:var(--accent);
  padding:9px 18px;border-radius:999px;transition:transform .15s,box-shadow .2s}
.enter-mini:hover{transform:translateY(-1px);box-shadow:0 0 20px rgba(127,216,255,.5)}

/* ---------- journey rail ---------- */
#rail{position:fixed;right:26px;top:50%;transform:translateY(-50%);z-index:40;display:flex;flex-direction:column;gap:22px}
#rail a{display:flex;align-items:center;gap:10px;flex-direction:row-reverse;text-decoration:none}
#rail i{width:9px;height:9px;border-radius:50%;border:1.5px solid var(--faint);display:block;transition:all .3s}
#rail span{font-size:11px;letter-spacing:.14em;color:var(--faint);opacity:0;transform:translateX(6px);transition:all .3s;text-transform:uppercase}
#rail a:hover span{opacity:1;transform:none}
#rail a.on i{background:var(--accent);border-color:var(--accent);box-shadow:0 0 12px rgba(127,216,255,.8)}
#rail a.on span{opacity:1;transform:none;color:var(--accent)}
#odometer{position:fixed;left:26px;bottom:22px;z-index:40;font-size:11px;letter-spacing:.18em;color:var(--faint);
  opacity:0;transition:opacity .4s}
#odometer.on{opacity:.9}
#odo-text{border-left:2px solid rgba(127,216,255,.4);padding-left:10px}

/* ---------- shared ---------- */
main{position:relative;z-index:1}
section{min-height:100vh;display:flex;flex-direction:column;justify-content:center;padding:120px 8vw;position:relative}
.kicker{font-size:12px;letter-spacing:.34em;color:var(--accent);margin-bottom:18px;font-weight:600}
h1,h2{font-weight:800;letter-spacing:.02em;line-height:1.08}
h2{font-size:clamp(30px,4.6vw,54px)}
.reveal{opacity:0;transform:translateY(34px);transition:opacity .9s cubic-bezier(.2,.7,.2,1),transform .9s cubic-bezier(.2,.7,.2,1)}
.reveal.in{opacity:1;transform:none}
.reveal.d1{transition-delay:.12s}.reveal.d2{transition-delay:.24s}.reveal.d3{transition-delay:.36s}
.reveal.d4{transition-delay:.48s}.reveal.d5{transition-delay:.6s}

/* ---------- hero ---------- */
.hero{align-items:flex-start;padding-top:16vh}
.hero h1{font-size:clamp(46px,9vw,118px);letter-spacing:.06em}
.hero h1 .thin{font-weight:200;color:var(--accent)}
.hero-sub{font-size:clamp(18px,2.4vw,26px);color:var(--warm);margin-top:14px;letter-spacing:.04em}
.hero-body{max-width:560px;color:var(--dim);margin-top:18px}
.hero-cta{display:flex;gap:16px;margin-top:34px;flex-wrap:wrap}
.btn-primary{display:inline-block;text-decoration:none;background:linear-gradient(135deg,#7fd8ff,#4aa3dd);color:#04121f;
  font-weight:800;font-size:15px;letter-spacing:.05em;padding:15px 32px;border-radius:12px;transition:transform .15s,box-shadow .25s}
.btn-primary:hover{transform:translateY(-2px);box-shadow:0 6px 34px rgba(127,216,255,.45)}
.btn-primary.big{font-size:18px;padding:18px 44px}
.btn-ghost{display:inline-block;text-decoration:none;color:var(--dim);border:1px solid rgba(127,216,255,.3);
  padding:15px 26px;border-radius:12px;font-size:15px;transition:all .2s}
.btn-ghost:hover{color:var(--accent);border-color:var(--accent)}

.hero-planet{position:absolute;right:3vw;top:56%;width:clamp(210px,26vw,380px);aspect-ratio:1;transform:translateY(-50%);pointer-events:none;z-index:-1;opacity:.94}
.planet-globe{position:absolute;inset:14%;border-radius:50%;
  background:radial-gradient(circle at 32% 30%,#ffe9b8 0%,#e8b96f 34%,#8a6a3d 68%,#241a10 100%);
  box-shadow:inset -26px -20px 60px rgba(0,0,0,.7),0 0 70px rgba(255,210,127,.18)}
.planet-ring{position:absolute;inset:-6% -14%;border-radius:50%;border:2px solid rgba(255,226,166,.5);
  border-left-color:transparent;border-right-color:rgba(255,226,166,.16);transform:rotateX(72deg) rotateZ(-16deg);
  animation:ringtilt 14s ease-in-out infinite alternate}
@keyframes ringtilt{from{transform:rotateX(70deg) rotateZ(-18deg)}to{transform:rotateX(74deg) rotateZ(-13deg)}}
.planet-moon{position:absolute;width:10px;height:10px;border-radius:50%;background:#cfe7f7;top:50%;left:50%;
  animation:moonorbit 11s linear infinite}
.planet-moon.m2{width:6px;height:6px;background:#9fc2d8;animation-duration:19s;animation-delay:-7s}
@keyframes moonorbit{
  from{transform:rotate(0deg) translateX(clamp(130px,17vw,235px)) rotate(0deg)}
  to  {transform:rotate(360deg) translateX(clamp(130px,17vw,235px)) rotate(-360deg)}}
.scroll-cue{position:absolute;bottom:34px;left:50%;transform:translateX(-50%);width:26px;height:42px;
  border:2px solid rgba(127,216,255,.4);border-radius:14px}
.scroll-cue span{position:absolute;left:50%;top:8px;width:4px;height:8px;margin-left:-2px;border-radius:3px;
  background:var(--accent);animation:cue 1.8s ease-in-out infinite}
@keyframes cue{0%{transform:translateY(0);opacity:1}70%{transform:translateY(14px);opacity:0}100%{opacity:0}}

/* ---------- realms ---------- */
.realm{display:grid;grid-template-columns:1.05fr .95fr;gap:6vw;align-items:center}
.realm.flip .realm-copy{order:2}
.realm.flip .realm-art{order:1}
.realm-copy p{color:var(--dim);max-width:520px;margin-top:16px}
.stats{display:flex;gap:34px;margin-top:30px;flex-wrap:wrap}
.stat b{display:block;font-size:clamp(26px,3vw,40px);color:var(--accent);font-weight:800;letter-spacing:.02em}
.stat span{font-size:12.5px;color:var(--faint);letter-spacing:.05em}
.realm-art{position:relative;aspect-ratio:1;max-width:440px;width:100%;justify-self:center}

/* solar art */
.art-solar .sun-dot{position:absolute;left:50%;top:50%;width:34px;height:34px;margin:-17px;border-radius:50%;
  background:radial-gradient(circle at 35% 35%,#fff5d6,#ffd27f 55%,#c77b2e);box-shadow:0 0 44px rgba(255,210,127,.75)}
.orbit{position:absolute;left:50%;top:50%;border:1px solid rgba(127,216,255,.2);border-radius:50%;transform:translate(-50%,-50%)}
.orbit i{position:absolute;top:-5px;left:50%;width:10px;height:10px;margin-left:-5px;border-radius:50%;background:#9fd8ff}
.orbit i.ringed{background:#ffe2a6;box-shadow:0 0 0 3px rgba(255,226,166,.25)}
.o1{width:26%;height:26%;animation:spin 9s linear infinite}
.o2{width:46%;height:46%;animation:spin 16s linear infinite}
.o3{width:66%;height:66%;animation:spin 26s linear infinite}
.o4{width:88%;height:88%;animation:spin 40s linear infinite}
@keyframes spin{from{transform:translate(-50%,-50%) rotate(0)}to{transform:translate(-50%,-50%) rotate(360deg)}}

/* stellar art */
.constellation{width:100%;height:auto;overflow:visible}
.constellation polyline{fill:none;stroke:rgba(127,216,255,.55);stroke-width:1.4;
  stroke-dasharray:600;stroke-dashoffset:600;transition:stroke-dashoffset 2.4s ease .3s}
.in ~ .art-stellar .constellation polyline, .art-stellar.in .constellation polyline{stroke-dashoffset:0}
.cstars circle{fill:#dff2ff;filter:drop-shadow(0 0 6px rgba(159,216,255,.9));animation:tw 3s ease-in-out infinite alternate}
.cstars circle:nth-child(2n){animation-delay:1.2s}
@keyframes tw{from{opacity:.55}to{opacity:1}}

/* galaxy art */
.art-galaxy .spiral{position:absolute;inset:6%;border-radius:50%;filter:blur(7px);opacity:.9;
  background:conic-gradient(from 0deg,transparent 0deg,rgba(191,150,255,.55) 40deg,transparent 90deg,
    rgba(127,216,255,.4) 150deg,transparent 200deg,rgba(213,170,255,.5) 260deg,transparent 320deg);
  animation:spinplain 36s linear infinite}
@keyframes spinplain{from{transform:rotate(0)}to{transform:rotate(360deg)}}
.art-galaxy .core{position:absolute;left:50%;top:50%;width:60px;height:60px;margin:-30px;border-radius:50%;
  background:radial-gradient(circle,#fff8e8,#f6d9a0 45%,transparent 72%);box-shadow:0 0 60px rgba(246,217,160,.6)}

/* universe art */
.deepfield{position:absolute;inset:4%;border-radius:50%;overflow:hidden;
  box-shadow:inset 0 0 90px rgba(120,80,180,.14),0 0 0 1px rgba(127,216,255,.12)}
.deepfield i{position:absolute;border-radius:50%;display:block}

/* exo art */
.exo-star{position:absolute;left:50%;top:50%;width:26px;height:26px;margin:-13px;border-radius:50%;
  background:radial-gradient(circle at 35% 35%,#ffd9c4,#ff8f6b 60%,#8a2f16);box-shadow:0 0 34px rgba(255,143,107,.7)}
.exo-orbit{position:absolute;left:50%;top:50%;border:1px solid rgba(127,216,255,.22);border-radius:50%;transform:translate(-50%,-50%)}
.exo-orbit i{position:absolute;top:-4px;left:50%;width:9px;height:9px;margin-left:-4px;border-radius:50%;background:#bfe9ff}
.e1{width:30%;height:30%;animation:spin 7s linear infinite}
.e2{width:54%;height:54%;animation:spin 13s linear infinite}
.e3{width:80%;height:80%;animation:spin 22s linear infinite}
.e3.hz{border-color:rgba(120,255,180,.45);box-shadow:0 0 26px rgba(120,255,180,.12) inset}
.e3.hz i{background:#a8f2c8}

/* ---------- instruments ---------- */
.instruments{align-items:center;text-align:center}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:22px;margin-top:48px;max-width:1060px}
.card{background:rgba(10,22,38,.5);border:1px solid rgba(127,216,255,.14);border-radius:16px;padding:28px 22px;
  text-align:left;backdrop-filter:blur(6px);transition:transform .25s,border-color .25s,box-shadow .25s}
.card:hover{transform:translateY(-5px);border-color:rgba(127,216,255,.45);box-shadow:0 14px 40px rgba(3,10,20,.6)}
.card i{font-style:normal;font-size:24px;display:block;margin-bottom:12px}
.card b{display:block;font-size:16px;letter-spacing:.04em;margin-bottom:8px}
.card p{font-size:13.5px;color:var(--faint);line-height:1.6}

/* ---------- mission ---------- */
.mission{align-items:center;text-align:center}
.mission blockquote p{font-size:clamp(20px,2.6vw,30px);line-height:1.5;color:var(--dim);max-width:760px}
.mission blockquote .em{margin-top:18px;color:var(--ink);font-weight:700}
.mission blockquote .em::after{content:"";display:block;width:70px;height:2px;margin:26px auto 0;
  background:linear-gradient(90deg,transparent,var(--accent),transparent)}
.mission-note{margin-top:30px;font-size:13px;letter-spacing:.12em;color:var(--faint);text-transform:uppercase}

/* ---------- cta / footer ---------- */
.cta{align-items:center;text-align:center;min-height:88vh}
.cta h2{font-size:clamp(34px,5.4vw,64px)}
.cta .btn-primary{margin-top:36px}
.cta-note{margin-top:18px;color:var(--faint);font-size:13.5px}
footer{display:flex;gap:26px;justify-content:center;align-items:center;flex-wrap:wrap;
  padding:34px 20px;border-top:1px solid rgba(127,216,255,.1);font-size:12px;letter-spacing:.1em;color:var(--faint)}
footer a{color:var(--accent);text-decoration:none}

/* ---------- responsive ---------- */
@media (max-width:940px){
  #rail{display:none}
  .realm{grid-template-columns:1fr;gap:40px}
  .realm.flip .realm-copy{order:1}
  .realm.flip .realm-art{order:2}
  .realm-art{max-width:300px}
  .grid{grid-template-columns:1fr 1fr}
  .hero-planet{position:relative;right:auto;top:auto;transform:none;margin:60px auto 0;width:230px}
  .hero{align-items:center;text-align:center;padding-top:12vh}
  .hero-cta{justify-content:center}
  section{padding:90px 7vw}
}
@media (max-width:600px){
  .grid{grid-template-columns:1fr}
  #odometer{display:none}
  .stats{gap:22px}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,.reveal{animation:none!important;transition:none!important}
  .reveal{opacity:1;transform:none}
  .constellation polyline{stroke-dashoffset:0}
}