:root{
  --bg:#0b0f14; --card:#111820; --card2:#0e151d; --line:#1f2a37; --text:#e8eef6;
  --muted:#93a4b8; --faint:#64748b; --accent:#6ea8fe; --accent2:#2f6fed;
  --ok:#34d399; --warn:#fbbf24; --bad:#fb7185; --tap:46px;
}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent}
html,body{margin:0;background:var(--bg);color:var(--text);font:16px/1.45 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif}
body{padding-bottom:calc(64px + env(safe-area-inset-bottom))}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
.top{position:sticky;top:0;z-index:20;background:rgba(11,15,20,.94);backdrop-filter:blur(12px);border-bottom:1px solid var(--line);padding-top:env(safe-area-inset-top)}
.top-inner{max-width:560px;margin:0 auto;padding:10px 16px;display:flex;align-items:center;gap:12px;min-height:60px}
.top-text{min-width:0;flex:1}
.eyebrow{margin:0;color:var(--muted);font-size:10px;font-weight:800;letter-spacing:.1em;text-transform:uppercase}
#title{margin:0;font-size:22px;font-weight:800;letter-spacing:-.02em}
.top-progress{font-size:12px;color:var(--muted);text-align:right;font-variant-numeric:tabular-nums}
.top-progress b{color:var(--text)}
main{max-width:560px;margin:0 auto;padding:14px 16px 30px}
.card{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:16px;margin:0 0 12px}
.card.soft{background:var(--card2)}
h2{font-size:20px;margin:0 0 6px;letter-spacing:-.02em}
h3{font-size:13px;margin:0 0 8px;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}
p{margin:0 0 10px}
.muted{color:var(--muted)}
.small{font-size:12px}
.tiny{font-size:11px}
.row{display:flex;gap:10px;align-items:center}
.row.wrap{flex-wrap:wrap}
.spacer{flex:1}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:var(--tap);padding:0 16px;border-radius:12px;border:1px solid var(--line);background:#16202b;font-weight:700;color:var(--text);width:100%}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#04101f}
.btn.ghost{background:transparent;color:var(--muted)}
.btn.small{width:auto;min-height:38px;padding:0 12px;font-size:13px}
.btn:disabled{opacity:.4}
.btn-row{display:flex;gap:8px;margin-top:10px}
.btns2{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.badge{display:inline-flex;align-items:center;gap:5px;border:1px solid var(--line);background:var(--card2);border-radius:999px;padding:3px 8px;font-size:10px;font-weight:800;letter-spacing:.04em;color:var(--muted);text-transform:uppercase}
.badge.ok{color:var(--ok);border-color:rgba(52,211,153,.4)}
.badge.warn{color:var(--warn);border-color:rgba(251,191,36,.4)}
.badge.bad{color:var(--bad);border-color:rgba(251,113,133,.4)}
.badge.acc{color:var(--accent);border-color:rgba(110,168,254,.45)}
.math{overflow-x:auto;padding:2px 0}
.math .katex-display{margin:.35em 0}
.statement{color:var(--text);font-size:15px}
.intuition{color:var(--muted);font-size:13px;font-style:italic}
.option{display:block;width:100%;text-align:left;border:1px solid var(--line);background:var(--card2);border-radius:12px;padding:12px;margin:0 0 8px;min-height:var(--tap)}
.option.correct{border-color:var(--ok);background:rgba(52,211,153,.08)}
.option.wrong{border-color:var(--bad);background:rgba(251,113,133,.08)}
.option .letter{display:inline-block;width:20px;color:var(--muted);font-weight:800}
.feedback{border-radius:12px;padding:10px 12px;margin-top:8px;font-size:13px}
.feedback.ok{background:rgba(52,211,153,.08);border:1px solid rgba(52,211,153,.35)}
.feedback.bad{background:rgba(251,113,133,.08);border:1px solid rgba(251,113,133,.35)}
.grades{display:grid;grid-template-columns:repeat(5,1fr);gap:6px;margin-top:8px}
.grades button{border:1px solid var(--line);background:var(--card2);border-radius:10px;min-height:48px;font-weight:800}
.grades button:hover{border-color:var(--accent)}
.timer{font-variant-numeric:tabular-nums;font-weight:800;font-size:22px;color:var(--accent)}
.ready{border:1px dashed var(--line);border-radius:12px;padding:12px;background:rgba(110,168,254,.04)}
.steps{counter-reset:s;margin:10px 0 0;padding:0;list-style:none}
.steps li{position:relative;padding:8px 0 8px 34px;border-top:1px solid var(--line);font-size:13px}
.steps li:before{counter-increment:s;content:counter(s);position:absolute;left:0;top:8px;width:22px;height:22px;border-radius:50%;background:#1b2836;color:var(--accent);font-size:11px;font-weight:800;display:grid;place-items:center}
.bloom{font-size:9px;font-weight:800;color:#04101f;background:var(--accent);border-radius:4px;padding:1px 4px;margin-right:6px}
.grid{display:grid;grid-template-columns:repeat(6,1fr);gap:6px}
.cell{aspect-ratio:1;border-radius:9px;border:1px solid var(--line);display:grid;place-items:center;font-size:10px;font-weight:800;color:var(--muted);background:#0e151d}
.cell.tapped{background:#16293f;color:#bcdcff;border-color:#24486e}
.cell.quiz{background:#3a2f14;color:#ffdf9a;border-color:#6b571f}
.cell.correct{background:#123528;color:#a7f3d0;border-color:#1f6f52}
.cell.red{background:#3a1620;color:#ffb3c1;border-color:#7f2438}
.legend{display:flex;gap:10px;flex-wrap:wrap;font-size:11px;color:var(--muted);margin-top:10px}
.dot{display:inline-block;width:9px;height:9px;border-radius:50%;margin-right:4px}
.nav{position:fixed;left:0;right:0;bottom:0;z-index:30;background:rgba(13,19,26,.97);border-top:1px solid var(--line);padding-bottom:env(safe-area-inset-bottom)}
.nav-inner{display:grid;grid-template-columns:repeat(4,1fr);max-width:560px;margin:0 auto;padding:6px 8px}
.nav button{min-height:52px;border-radius:10px;color:var(--faint);font-size:11px;font-weight:800}
.nav button.active{color:var(--accent);background:rgba(110,168,254,.1)}
.bars{display:grid;gap:8px}
.bar{display:grid;grid-template-columns:1fr auto;gap:4px 10px;font-size:12px}
.bar .track{grid-column:1/-1;height:7px;background:#0d1620;border-radius:99px;overflow:hidden}
.bar .fill{height:100%;background:var(--accent);border-radius:99px}
.kpi{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.kpi .card{margin:0;padding:12px}
.kpi .n{font-size:26px;font-weight:800;letter-spacing:-.03em}
.guide-step{display:flex;gap:10px;margin:0 0 10px}
.guide-step .num{flex:none;width:26px;height:26px;border-radius:50%;background:var(--accent);color:#04101f;font-weight:900;display:grid;place-items:center;font-size:12px}
.guide-step b{display:block;font-size:14px}
.study-head{display:flex;align-items:center;gap:8px;margin-bottom:6px}
.study-head .id{color:var(--faint);font-size:11px;font-weight:700}
.stage-label{font-size:10px;font-weight:800;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);margin:0 0 6px}
.toast{position:fixed;left:50%;bottom:calc(78px + env(safe-area-inset-bottom));transform:translateX(-50%);background:#1b2836;border:1px solid var(--line);color:var(--text);padding:9px 14px;border-radius:10px;font-size:12px;opacity:0;pointer-events:none;transition:.2s;max-width:90vw;text-align:center}
.toast.show{opacity:1}
.hr{height:1px;background:var(--line);margin:12px 0}
.center{text-align:center}
.big{font-size:30px;font-weight:800;letter-spacing:-.03em}
@media (min-width:600px){.grid{grid-template-columns:repeat(8,1fr)}}