:root{
  --bg:#05070f; --panel:rgba(12,20,44,.82); --line:#2f6bff; --glow:#4aa3ff;
  --text:#d6e4ff; --dim:#7d92bd; --ok:#3ddc97; --bad:#ff5d73; --gold:#ffcf5c; --violet:#9b6bff;
}
*{box-sizing:border-box}
body{margin:0;background:radial-gradient(1200px 600px at 70% -10%,#0d1b45 0,#05070f 60%) fixed;color:var(--text);
  font:15px/1.5 "Segoe UI",system-ui,sans-serif;min-height:100vh}
header{display:flex;align-items:center;gap:24px;padding:12px 28px;border-bottom:1px solid #16254f;background:#060a18cc;position:sticky;top:0;z-index:5}
.logo{font-weight:800;letter-spacing:.25em;color:var(--glow);text-shadow:0 0 12px var(--glow)}
nav{display:flex;gap:6px;flex:1}
nav button{background:none;border:1px solid transparent;color:var(--dim);padding:6px 14px;cursor:pointer;letter-spacing:.08em;text-transform:uppercase;font-size:12px}
nav button.on,nav button:hover{color:var(--text);border-color:var(--line);box-shadow:0 0 10px #2f6bff55 inset}
.mini{display:flex;align-items:center;gap:10px;font-size:13px}
.lang{background:#050a1c;border:1px solid #1d3a8a;color:var(--text);padding:4px 8px;font:inherit;font-size:12px;cursor:pointer}
.rank{width:30px;height:30px;display:grid;place-items:center;border:1px solid var(--gold);color:var(--gold);font-weight:800;transform:rotate(45deg)}
.rank b{transform:rotate(-45deg)}
main{max-width:1180px;margin:24px auto;padding:0 20px}
.screen{display:none}.screen.on{display:block}
.win{background:var(--panel);border:1px solid var(--line);box-shadow:0 0 22px #2f6bff40,inset 0 0 30px #2f6bff14;padding:18px 20px;position:relative;margin-bottom:18px}
.win>h3{margin:-18px -20px 14px;padding:7px 20px;font-size:12px;letter-spacing:.2em;text-transform:uppercase;color:var(--glow);border-bottom:1px solid #1d3a8a;background:#0a1534}
.grid{display:grid;gap:18px}
.g2{grid-template-columns:1fr 1.2fr}.g3{grid-template-columns:repeat(3,1fr)}
.bar{height:10px;background:#0a1230;border:1px solid #1d3a8a}
.bar i{display:block;height:100%;background:linear-gradient(90deg,#2f6bff,#6fd0ff);box-shadow:0 0 10px var(--glow)}
.row{display:flex;justify-content:space-between;align-items:center;gap:10px}
.dim{color:var(--dim)}.gold{color:var(--gold)}.ok{color:var(--ok)}.bad{color:var(--bad)}
.stat{display:grid;grid-template-columns:90px 1fr 36px;gap:10px;align-items:center;margin:6px 0;font-size:13px}
.quest{display:flex;gap:10px;align-items:center;padding:8px 0;border-bottom:1px dashed #1d2f66}
.chk{width:16px;height:16px;border:1px solid var(--glow)}.chk.d{background:var(--ok);border-color:var(--ok)}
button.cta{background:linear-gradient(#1d4fd8,#163aa3);color:#fff;border:1px solid var(--glow);padding:10px 22px;letter-spacing:.12em;text-transform:uppercase;cursor:pointer;box-shadow:0 0 14px #2f6bff88}
button.cta:hover{filter:brightness(1.2)}
button.ghost{background:none;color:var(--text);border:1px solid #2a3f7d;padding:8px 14px;cursor:pointer}
button.ghost:hover{border-color:var(--glow)}
.title{font-size:26px;font-weight:700;margin:0 0 4px}
.tag{display:inline-block;border:1px solid var(--violet);color:var(--violet);padding:0 8px;font-size:11px;letter-spacing:.12em;text-transform:uppercase}
/* gate map */
.map{position:relative;height:520px;background:
  radial-gradient(circle at 50% 100%,#12276b55,transparent 60%),repeating-linear-gradient(0deg,transparent 0 39px,#10204a 39px 40px)}
.map svg{position:absolute;inset:0;width:100%;height:100%}
.node{position:absolute;transform:translate(-50%,-50%);width:150px;text-align:center;font-size:12px;cursor:pointer}
.node .o{width:46px;height:46px;margin:0 auto 4px;display:grid;place-items:center;border:2px solid var(--glow);background:#0a1534;font-weight:800;
  transform:rotate(45deg);box-shadow:0 0 14px #4aa3ff88}
.node .o span{transform:rotate(-45deg)}
.node.done .o{border-color:var(--ok);box-shadow:0 0 14px #3ddc9788;color:var(--ok)}
.node.lock{opacity:.45}.node.lock .o{border-color:#33406b;box-shadow:none}
.node.boss .o{border-color:var(--bad);box-shadow:0 0 18px #ff5d7388;color:var(--bad)}
/* exercise */
.problem{font-size:18px}
.tiles{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0}
.tile{width:44px;height:44px;display:grid;place-items:center;border:1px solid var(--glow);background:#0a1534;font-weight:700;font-size:18px}
table{border-collapse:collapse;width:100%;margin:8px 0}
th,td{border:1px solid #1d3a8a;padding:8px 10px;text-align:center}
th{color:var(--glow);font-size:12px;letter-spacing:.1em;text-transform:uppercase;background:#0a1534}
td input,.formula{background:#050a1c;border:1px solid var(--glow);color:var(--text);padding:6px 10px;font:inherit;width:100%;text-align:center}
td input{width:90px}
.formula{text-align:left;font-family:ui-monospace,Menlo,monospace;font-size:16px}
.sys{border-left:3px solid var(--glow);background:#081230;padding:10px 14px;margin:10px 0;font-size:14px}
.sys b{color:var(--glow);letter-spacing:.15em;font-size:11px;display:block}
.sys.good{border-color:var(--ok)}.sys.good b{color:var(--ok)}
.sys.warn{border-color:var(--bad)}.sys.warn b{color:var(--bad)}
.steps{display:flex;gap:6px;margin-bottom:14px;font-size:11px;letter-spacing:.08em;text-transform:uppercase}
.steps div{flex:1;padding:5px 0;text-align:center;border-bottom:3px solid #1d2f66;color:var(--dim)}
.steps .d{border-color:var(--ok);color:var(--ok)}.steps .c{border-color:var(--glow);color:var(--text)}
.shadow{text-align:center;padding:14px 8px;border:1px solid #3b2a7a;background:#0d0a22}
.shadow .ic{font-size:34px;filter:drop-shadow(0 0 8px var(--violet))}
.shadow.fade{opacity:.55;border-color:var(--bad)}
.radar{display:block;margin:0 auto}
.gri{border-bottom:1px dashed #1d2f66;padding:10px 0}
.gri code{color:var(--gold);font-size:17px}
.note{font-size:12px;color:var(--dim);text-align:center;margin:30px 0 10px}
@media(max-width:860px){.g2,.g3{grid-template-columns:1fr}nav{overflow:auto}}

/* ---- app additions ---- */
.boot{display:grid;place-items:center;min-height:100vh;color:var(--glow);letter-spacing:.12em}
button{font:inherit}
.big{font-size:34px;font-weight:800}.small{font-size:12px}.mt{margin-top:14px}.mb{margin-bottom:12px}
.b{font-weight:700}.i{font-style:italic}
.facts{display:flex;gap:22px;flex-wrap:wrap;margin-top:16px}.facts b{font-size:20px;color:var(--gold)}
ul{margin:6px 0 14px;padding-left:20px}
h4{margin:14px 0 4px;color:var(--glow);letter-spacing:.1em;text-transform:uppercase;font-size:12px}
.maprow{display:flex;justify-content:center;gap:28px;margin:16px 0}
.map{height:auto;padding:12px 0}
button.node{position:static;transform:none;background:none;border:0;color:inherit;width:170px}
button.node:disabled{cursor:not-allowed}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:14px}
.steps div{flex:0 0 auto;min-width:36px;padding:5px 8px}
.answer{display:flex;gap:10px;margin-top:12px}
.choices{display:grid;gap:8px;margin-top:12px}
.choice{text-align:left;background:#0a1534;border:1px solid #2a3f7d;color:var(--text);padding:10px 14px;cursor:pointer}
.choice:hover:not(:disabled){border-color:var(--glow)}
.choice.wrong{border-color:var(--bad);opacity:.6}
.tbl input{width:90px}
.math.raw{color:var(--gold)}
button:disabled{opacity:.5;cursor:not-allowed}
.gri ul{margin:4px 0 0}