*{box-sizing:border-box}html,body{margin:0;padding:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background:#0f172a;color:#e2e8f0}
header{padding:24px 16px 8px;border-bottom:1px solid #334155;background:#0b1220}
h1{margin:0 0 6px 0;font-size:28px}
.tagline{margin:0;color:#93c5fd}
main{padding:16px;max-width:1200px;margin:0 auto}
.cards{display:grid;grid-template-columns:1fr;gap:16px}
@media(min-width:960px){.cards{grid-template-columns:1fr 1fr}}
.card{background:#111827;border:1px solid #374151;border-radius:12px;padding:16px;box-shadow:0 1px 0 rgba(255,255,255,0.05) inset}
.card h2{margin-top:0}
.formulae ul{margin:0 0 8px 18px}
.math{font-family:ui-monospace,Menlo,Consolas,monospace;background:#0b1220;padding:2px 6px;border-radius:6px}
.controls{display:grid;gap:10px;margin-bottom:10px}
.controls label{display:grid;grid-template-columns:1fr auto;align-items:center;gap:10px}
.controls input[type=range]{width:100%}
.inline{display:inline-flex;align-items:center;gap:6px;margin-left:12px}
.button-row{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin-top:6px}
.sim-wrap{background:#0b1220;border:1px solid #334155;border-radius:10px;overflow:hidden}
canvas{display:block;width:100%;height:auto;background:linear-gradient(#0b1220,#0b1220)}
.metrics{display:flex;gap:16px;flex-wrap:wrap;margin-top:10px}
.note{color:#93c5fd}
.legend{display:flex;gap:18px;align-items:center;margin:8px 0 0}
.legend .dot{width:12px;height:12px;border-radius:50%;display:inline-block}
.legend .current{background:#ffffff}
.legend .trail{background:#60a5fa}
.quiz{padding-left:18px}
.choices button{margin:6px 6px 0 0}
.feedback{min-height:20px;margin-top:6px}
.correct{color:#86efac}
.incorrect{color:#fca5a5}
footer{padding:20px 16px;color:#94a3b8;border-top:1px solid #334155;margin-top:16px;text-align:center}