:root{
  --bg0:#0a0e27; --bg1:#141a44; --ink:#ffffff; --muted:#c3cbf0;
  --card:#1b2255; --accent:#ffd24a; --accent2:#7fd7ff;
  --pink:#ff8fc7; --green:#7be0a4;
  --safe: env(safe-area-inset-bottom, 0px);
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html{touch-action:manipulation;-ms-touch-action:manipulation;}
html,body{margin:0;height:100%;overflow:hidden;
  font-family:'Baloo 2',system-ui,-apple-system,'Segoe UI',sans-serif;
  color:var(--ink);background:var(--bg0);user-select:none;-webkit-user-select:none;}

/* ---------- starfield ---------- */
#sky{position:fixed;inset:0;z-index:0;overflow:hidden;
  background:linear-gradient(rgba(5,7,26,.35),rgba(5,7,26,.55)),url("/static/explore-bg.webp") center/cover no-repeat;}
.star{position:absolute;border-radius:50%;background:#fff;animation:tw 3s infinite ease-in-out;}
@keyframes tw{0%,100%{opacity:.25}50%{opacity:1}}

/* ---------- top bar ---------- */
#topbar{position:fixed;top:0;left:0;right:0;z-index:30;display:flex;
  align-items:center;justify-content:space-between;
  padding:14px 16px calc(14px);pointer-events:none;}
#topbar .title{font-size:clamp(18px,5vw,26px);font-weight:800;
  text-shadow:0 2px 8px rgba(0,0,0,.5);pointer-events:none;
  display:flex;align-items:center;gap:8px;}
.iconbtn{pointer-events:auto;width:48px;height:48px;border:none;border-radius:16px;
  background:rgba(255,255,255,.14);backdrop-filter:blur(6px);
  color:#fff;font-size:24px;cursor:pointer;display:grid;place-items:center;
  box-shadow:0 4px 12px rgba(0,0,0,.3);transition:transform .1s;}
.iconbtn:active{transform:scale(.9);}
.topbtns{pointer-events:auto;display:flex;gap:10px;}

/* systems chooser cards */
#syslist{display:flex;flex-direction:column;gap:12px;margin-bottom:6px;}
.syscard{display:flex;align-items:center;gap:14px;width:100%;text-align:left;
  border:none;border-radius:18px;padding:16px;cursor:pointer;font-family:inherit;
  background:rgba(0,0,0,.25);color:#fff;transition:transform .1s,background .15s;}
.syscard:active{transform:scale(.98);}
.syscard.on{background:rgba(255,210,74,.16);box-shadow:inset 0 0 0 2px var(--accent);}
.syscard .sysemoji{font-size:34px;line-height:1;}
.syscard .systxt{display:flex;flex-direction:column;flex:1;}
.syscard .sysname{font-size:19px;font-weight:800;}
.syscard .syssub{font-size:14px;color:var(--muted);}
.syscard .syshere{font-size:12px;font-weight:800;color:#3a2a00;
  background:var(--accent);border-radius:10px;padding:5px 9px;}

/* fun "maybe oceans" badge under special planets */
.planet-badge{margin-top:8px;display:inline-block;font-size:14px;font-weight:800;
  color:#062a3a;background:linear-gradient(180deg,#8fe3ff,#4bc0e6);
  padding:6px 12px;border-radius:14px;box-shadow:0 3px 10px rgba(75,192,230,.45);
  white-space:nowrap;animation:badgepulse 2.4s ease-in-out infinite;}
@keyframes badgepulse{0%,100%{transform:scale(1)}50%{transform:scale(1.07)}}

/* warp flash when switching systems */
@keyframes warpflash{0%{opacity:0}30%{opacity:.55}100%{opacity:0}}
body.warp::after{content:"";position:fixed;inset:0;z-index:80;pointer-events:none;
  background:radial-gradient(circle at 50% 50%, #fff 0%, #9db8ff 40%, transparent 75%);
  animation:warpflash .5s ease-out;}

/* ---------- free-scrolling space strip ---------- */
#stage{position:relative;z-index:10;height:100%;display:flex;align-items:center;
  overflow-x:auto;overflow-y:hidden;-webkit-overflow-scrolling:touch;
  scrollbar-width:none;cursor:grab;
  scroll-padding-left:6vw;
  /* generous side padding so first/last planet can sit centered-ish */
  padding:0 12vw;gap:min(var(--planet-gap, 54vw), 540px);}
#stage::-webkit-scrollbar{display:none;}
#stage.grabbing{cursor:grabbing;}
.item{flex:0 0 auto;display:flex;flex-direction:column;align-items:center;justify-content:center;
  height:100%;}
.planet-wrap{position:relative;display:flex;flex-direction:column;align-items:center;gap:14px;
  cursor:pointer;animation:float 5s ease-in-out infinite;}
.item:nth-child(even) .planet-wrap{animation-duration:6.5s;animation-delay:-1.5s;}
@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-16px)}}
.planet-img{height:auto;filter:drop-shadow(0 18px 30px rgba(0,0,0,.55));
  transition:transform .15s;pointer-events:auto;}
.planet-wrap:active .planet-img{transform:scale(.94);}
/* Bigger tap target for the star without changing its look: a transparent,
   centered hit-pad that extends ~80px beyond the star image on every side. */
.item.is-star .planet-stack::after{content:"";position:absolute;top:50%;left:50%;
  width:calc(100% + 160px);height:calc(100% + 160px);transform:translate(-50%,-50%);
  border-radius:50%;z-index:5;}
.planet-stack{position:relative;display:grid;place-items:center;}

/* Moon orbiting Earth */
.orbit{position:absolute;left:50%;top:50%;transform:translate(-50%,-50%);
  pointer-events:none;animation:orbit 6s linear infinite;}
@keyframes orbit{from{transform:translate(-50%,-50%) rotate(0deg)}
                 to{transform:translate(-50%,-50%) rotate(360deg)}}
.moon-wrap{position:absolute;left:50%;top:0;transform:translateX(-50%);
  pointer-events:auto;animation:none;}
.moon-img{filter:drop-shadow(0 4px 8px rgba(0,0,0,.5));
  animation:orbit-counter 6s linear infinite;}
@keyframes orbit-counter{from{transform:rotate(0deg)}to{transform:rotate(-360deg)}}
.moon-wrap:active .moon-img{transform:scale(.9);}

/* decorative little moons around other planets (not clickable) */
.orbit-tilt{position:absolute;left:50%;top:50%;pointer-events:none;}
.orbit.deco{position:absolute;left:50%;top:50%;pointer-events:none;}
.orbit.deco .dmoon{position:absolute;left:50%;top:0;transform:translateX(-50%);
  border-radius:50%;box-shadow:0 2px 5px rgba(0,0,0,.5),inset -2px -2px 3px rgba(0,0,0,.35);}

.planet-name{font-size:clamp(24px,6.5vw,40px);font-weight:800;
  text-shadow:0 3px 10px rgba(0,0,0,.5);white-space:nowrap;}

/* gentle first-visit hint */
#scrollhint{position:fixed;left:0;right:0;bottom:calc(20px + var(--safe));z-index:26;
  text-align:center;color:var(--muted);font-weight:700;font-size:clamp(15px,4.2vw,19px);
  pointer-events:none;text-shadow:0 2px 8px rgba(0,0,0,.6);transition:opacity .5s;
  display:flex;align-items:center;justify-content:center;gap:10px;}
#scrollhint .swipe{display:inline-block;animation:swipeh 1.6s infinite;}
@keyframes swipeh{0%,100%{transform:translateX(-6px)}50%{transform:translateX(6px)}}
#scrollhint.gone{opacity:0;}

#realnote{position:fixed;left:12px;right:12px;top:calc(60px + var(--safe));z-index:24;
  margin:0 auto;max-width:520px;text-align:center;
  background:rgba(10,14,39,.72);backdrop-filter:blur(6px);
  color:var(--muted);font-weight:600;font-size:clamp(12px,3.3vw,14px);line-height:1.35;
  padding:8px 14px;border-radius:14px;border:1px solid rgba(255,255,255,.12);
  box-shadow:0 4px 16px rgba(0,0,0,.35);pointer-events:none;}
#realnote[hidden]{display:none;}

/* ---------- info page (full screen) ---------- */
#info{position:fixed;inset:0;z-index:50;background:linear-gradient(160deg,#141a44,#0a0e27);
  display:flex;flex-direction:column;transform:translateY(100%);
  transition:transform .4s cubic-bezier(.22,1,.36,1);overflow-y:auto;overscroll-behavior:contain;}
#info.open{transform:translateY(0);}
#info .ihead{position:sticky;top:0;z-index:2;display:flex;align-items:center;
  justify-content:space-between;padding:14px 16px;
  background:linear-gradient(180deg,rgba(20,26,68,.96),rgba(20,26,68,0));backdrop-filter:blur(4px);}
#info .ihead h2{margin:0;font-size:clamp(24px,7vw,38px);font-weight:800;}
.photo-frame{flex:0 0 auto;margin:12px auto 0;border-radius:24px;overflow:hidden;position:relative;
  display:grid;place-items:center;width:max-content;max-width:calc(100% - 32px);
  background:#000;box-shadow:0 12px 30px rgba(0,0,0,.5);border:4px solid rgba(255,255,255,.14);}
.photo-frame img{display:block;max-width:100%;max-height:46vh;width:auto;height:auto;object-fit:contain;}
.photo-tag{position:absolute;bottom:8px;right:10px;font-size:12px;color:#fff;
  background:rgba(0,0,0,.55);padding:3px 9px;border-radius:20px;font-weight:600;}
.photo-frame.cartoon{display:grid;place-items:center;padding:18px;}
.photo-frame.cartoon img{width:auto;max-width:70%;max-height:38vh;}

/* audio player row */
.audiorow{display:flex;align-items:center;gap:12px;margin:16px 16px 6px;
  background:var(--card);border-radius:20px;padding:12px 14px;box-shadow:0 6px 16px rgba(0,0,0,.3);}
.playbtn{flex:0 0 auto;width:60px;height:60px;border:none;border-radius:50%;
  background:var(--accent);color:#3a2a00;font-size:30px;cursor:pointer;
  display:grid;place-items:center;box-shadow:0 4px 12px rgba(255,210,74,.5);transition:transform .1s;}
.playbtn:active{transform:scale(.9);}
.audiorow .alabel{font-weight:700;font-size:18px;}
.audiorow .asub{font-size:13px;color:var(--muted);font-weight:600;}

/* ---------- cutaway diagram ---------- */
.cutaway-sec{padding:14px 12px 4px;}
.cutaway-title{text-align:center;font-size:clamp(18px,5vw,22px);font-weight:800;margin:2px 0 4px;}
.cutaway-hint{text-align:center;font-size:14px;color:var(--muted);font-weight:600;margin:0 0 6px;}
.cutaway-wrap{position:relative;width:100%;max-width:520px;margin:0 auto;}
.cutaway-wrap svg{width:100%;height:auto;display:block;overflow:visible;}
.layer-seg{cursor:pointer;transition:opacity .15s;}
.layer-seg:active{opacity:.85;}
.layer-seg.dim{opacity:.45;}
.layer-seg.active{filter:drop-shadow(0 0 12px rgba(255,255,255,.9));}
.layer-lbl{font-family:inherit;font-weight:800;fill:#fff;paint-order:stroke;
  stroke:#0a0e27;stroke-width:5px;stroke-linejoin:round;}
.layer-lead{stroke:#fff;stroke-width:3.5;fill:none;stroke-linecap:round;}
.layer-dot{fill:#fff;}
/* popup fact bubble */
.layer-pop{margin:8px 14px 0;background:var(--card);border-radius:18px;padding:14px 16px;
  box-shadow:0 6px 16px rgba(0,0,0,.35);display:flex;gap:12px;align-items:center;
  opacity:0;transform:translateY(8px);transition:all .2s;pointer-events:none;}
.layer-pop.show{opacity:1;transform:translateY(0);pointer-events:auto;}
.layer-pop .swatch{flex:0 0 auto;width:34px;height:34px;border-radius:10px;border:3px solid rgba(255,255,255,.6);}
.layer-pop .ltxt .lname{font-weight:800;font-size:18px;}
.layer-pop .ltxt .lfact{font-size:15px;color:var(--muted);font-weight:600;line-height:1.4;}
.layer-pop .ltxt .lmat{margin-top:6px;font-size:14px;color:var(--ink);font-weight:700;line-height:1.35;}
.layer-pop .ltxt .lmat .matlabel{color:var(--accent);}
.layer-pop .lspk{flex:0 0 auto;width:44px;height:44px;border-radius:50%;border:none;
  background:var(--accent);color:#3a2a00;font-size:22px;cursor:pointer;display:grid;place-items:center;}

/* text facts */
.facts{padding:8px 20px 40px;font-size:clamp(18px,5vw,23px);line-height:1.55;font-weight:600;}
.facts.hidden{display:none;}
.facts ul{list-style:none;padding:0;margin:0;}
.facts li{display:flex;gap:12px;align-items:flex-start;margin:14px 0;}
.facts li .b{flex:0 0 auto;font-size:22px;}
.facts p{margin:0 0 16px;}

/* ---------- settings sheet ---------- */
.overlay{position:fixed;inset:0;z-index:60;background:rgba(4,6,20,.6);
  backdrop-filter:blur(3px);opacity:0;pointer-events:none;transition:opacity .25s;}
.overlay.open{opacity:1;pointer-events:auto;}
.sheet{position:fixed;left:0;right:0;bottom:0;z-index:61;background:#1b2255;
  border-radius:28px 28px 0 0;padding:22px 22px calc(30px + var(--safe));
  transform:translateY(110%);transition:transform .35s cubic-bezier(.22,1,.36,1);
  box-shadow:0 -10px 40px rgba(0,0,0,.5);}
.sheet.open{transform:translateY(0);}
.sheet h3{margin:0 0 4px;font-size:24px;font-weight:800;}
.sheet .grabber{width:44px;height:5px;border-radius:3px;background:rgba(255,255,255,.3);margin:0 auto 16px;}
.setrow{margin:18px 0;}
.setrow .q{font-size:17px;font-weight:700;color:var(--muted);margin-bottom:8px;}
.seg{display:flex;gap:8px;background:rgba(0,0,0,.25);border-radius:16px;padding:6px;}
.seg button{flex:1;border:none;border-radius:12px;padding:14px 8px;font-size:16px;font-weight:800;
  background:transparent;color:var(--muted);cursor:pointer;font-family:inherit;transition:all .15s;}
.seg button.on{background:var(--accent);color:#3a2a00;box-shadow:0 3px 8px rgba(255,210,74,.4);}
.donebtn{width:100%;margin-top:8px;border:none;border-radius:16px;padding:16px;
  font-size:19px;font-weight:800;background:var(--accent2);color:#04263a;cursor:pointer;font-family:inherit;}

/* hide arrows on touch-first small screens? keep, they're helpful */
@media (hover:none){.navarrow{background:rgba(255,255,255,.12);}}

/* ================= HOME SCREEN ================= */
#home{position:fixed;inset:0;z-index:40;display:none;align-items:center;justify-content:center;
  padding:24px;text-align:center;
  background:linear-gradient(rgba(5,7,26,.45),rgba(5,7,26,.65)),url("/static/home-bg.jpg") center/cover no-repeat;}
#home.open{display:flex;}
#home .home-inner{max-width:520px;width:100%;}
#home .home-title{font-size:clamp(34px,10vw,58px);font-weight:800;
  text-shadow:0 4px 18px rgba(0,0,0,.5);margin-bottom:6px;}
#home .home-sub{font-size:clamp(16px,4.5vw,22px);color:var(--muted);margin-bottom:28px;font-weight:700;}
#home .home-cards{display:flex;gap:18px;justify-content:center;flex-wrap:wrap;}
#home .home-card{flex:1 1 180px;max-width:230px;min-height:180px;border:none;cursor:pointer;
  border-radius:26px;padding:24px 18px;font-family:inherit;color:#fff;
  display:flex;flex-direction:column;align-items:center;justify-content:center;gap:8px;
  background:linear-gradient(160deg,#243089,#141a44);box-shadow:0 10px 30px rgba(0,0,0,.4);
  transition:transform .12s;}
#home .home-card:active{transform:scale(.95);}
#home #gotoPlay{background:linear-gradient(160deg,#8a3cc0,#4a1f76);}
#home .hc-emoji{font-size:56px;line-height:1;}
#home .hc-name{font-size:24px;font-weight:800;}
#home .hc-sub{font-size:15px;color:rgba(255,255,255,.75);font-weight:600;}
/* at home, hide the explore-only chrome */
body.at-home #scrollhint,body.at-home #realnote{display:none;}
body.at-home #systemsbtn,body.at-home #settingsbtn,body.at-home #homebtn{display:none;}
/* keep the explore stage hidden while on the home screen (no flash on load) */
body.at-home #stage{display:none;}

/* ================= BUILD-A-PLANET GAME ================= */
#game{position:fixed;inset:0;z-index:45;display:none;overflow-y:auto;
  background:
    linear-gradient(180deg, rgba(10,14,39,.72), rgba(10,14,39,.88)),
    url("/static/nebula.jpg") center/cover no-repeat fixed,
    radial-gradient(circle at 50% -10%,#1a2570,#0a0e27 70%);}
#game.open{display:block;}
#game .ghead{display:flex;align-items:center;justify-content:space-between;padding:16px 18px;}
#game .ghead h2{font-size:24px;font-weight:800;margin:0;}
#game .gpick-hint{text-align:center;color:var(--muted);font-weight:700;font-size:18px;margin:4px 0 16px;}
#game .gpick-random{display:block;margin:0 auto 8px;border:none;cursor:pointer;font-family:inherit;
  font-size:19px;font-weight:800;color:#3a2a00;border-radius:18px;padding:14px 28px;
  background:linear-gradient(160deg,#ffe17a,#ffc23c);box-shadow:0 6px 18px rgba(255,194,60,.45);
  transition:transform .1s;}
#game .gpick-random:active{transform:scale(.94);}
#game .gpick-sys{max-width:640px;margin:22px auto 10px;padding:0 20px;font-size:19px;font-weight:800;
  color:#fff;display:flex;align-items:center;gap:8px;}
#game .gpick-sys::after{content:"";flex:1;height:2px;border-radius:2px;background:rgba(255,255,255,.12);}
#game .gpick-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(96px,1fr));gap:14px;
  padding:0 18px 40px;max-width:640px;margin:0 auto;}
#game .gpick-card{background:rgba(255,255,255,.06);border:2px solid rgba(255,255,255,.08);
  border-radius:20px;padding:12px 8px;cursor:pointer;font-family:inherit;color:#fff;
  display:flex;flex-direction:column;align-items:center;gap:8px;transition:transform .12s,background .15s;}
#game .gpick-card:active{transform:scale(.93);}
#game .gpick-card img{width:64px;height:64px;object-fit:contain;pointer-events:none;}
#game .gpick-card span{font-size:13px;font-weight:800;line-height:1.15;text-align:center;}

/* puzzle */
.pz-wrap{max-width:520px;margin:0 auto;padding:0 20px 50px;display:flex;flex-direction:column;align-items:center;}
.pz-diagram{position:relative;width:min(80vw,320px);aspect-ratio:1;margin:6px auto 4px;}
.pz-svg{width:100%;height:100%;display:block;}
.pz-ring{transition:stroke .3s;}
.pz-ring.target{animation:pzpulse 1s ease-in-out infinite;}
@keyframes pzpulse{0%,100%{stroke:rgba(255,255,255,.18);}50%{stroke:rgba(127,215,255,.9);}}
.pz-planet{position:absolute;inset:0;margin:auto;width:78%;height:78%;object-fit:contain;
  animation:pzpop .5s cubic-bezier(.18,1.5,.4,1);}
@keyframes pzpop{0%{transform:scale(0);opacity:0;}100%{transform:scale(1);opacity:1;}}
.pz-say{font-size:20px;font-weight:800;text-align:center;margin:10px 0 16px;line-height:1.3;}
.pz-tray{display:flex;flex-wrap:wrap;gap:10px;justify-content:center;}
.pz-piece{display:flex;flex-direction:column;align-items:center;justify-content:flex-end;gap:6px;
  border:none;cursor:grab;font-family:inherit;font-size:14px;font-weight:800;color:#eaf0ff;
  background:rgba(255,255,255,.06);border:2px solid rgba(255,255,255,.10);border-radius:18px;
  padding:10px 12px;box-shadow:0 4px 12px rgba(0,0,0,.35);transition:transform .1s;}
.pz-piece{touch-action:none;user-select:none;-webkit-user-select:none;}
.pz-piece .pz-ringimg{display:block;pointer-events:none;}
.pz-piece .pz-ringimg svg{width:100%;height:100%;display:block;}
.pz-piece .pz-plabel{pointer-events:none;line-height:1.1;}
.pz-tray{align-items:flex-end;}
.pz-piece:active{transform:scale(.94);}
.pz-piece.dragging{opacity:.35;}
/* the floating copy that follows the finger/cursor while dragging */
.pz-ghost{position:fixed;z-index:90;transform:translate(-50%,-50%) scale(1.08);
  pointer-events:none;margin:0;box-shadow:0 10px 24px rgba(0,0,0,.5);opacity:.96;}
/* planet highlights when a piece hovers over it */
.pz-diagram.drop-hot .pz-svg{filter:drop-shadow(0 0 14px rgba(127,215,255,.9));}
.pz-piece.pop{animation:pzpiecepop .38s ease;}
@keyframes pzpiecepop{0%{transform:scale(1);}45%{transform:scale(1.25);}100%{transform:scale(0);opacity:0;}}
.pz-piece.wiggle{animation:pzwiggle .5s;}
@keyframes pzwiggle{0%,100%{transform:translateX(0);}20%{transform:translateX(-8px);}40%{transform:translateX(8px);}60%{transform:translateX(-6px);}80%{transform:translateX(6px);}}

.pz-again,.pz-back{border:none;cursor:pointer;font-family:inherit;font-size:18px;font-weight:800;
  border-radius:16px;padding:14px 22px;margin:4px;}
.pz-again{background:var(--accent);color:#3a2a00;}
.pz-back{background:rgba(255,255,255,.14);color:#fff;}