:root{--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark;--bg:#0e141b;--bg-elev:#151d27;--bg-hover:#1c2633;--text:#e8eef4;--muted:#8b9aab;--line:#243040;--accent:#5b9dff;--accent-2:#8ec0ff;--ok:#3ecf8e;--ok-bg:#123528;--bad:#ff6b6b;--bad-bg:#3a1518;--code:#0b1016;--shadow:0 10px 30px #00000047;--radius:14px;--sans:"Segoe UI", system-ui, sans-serif;--mono:ui-monospace, "Cascadia Code", Consolas, monospace;font-family:var(--sans);color:var(--text);background:var(--bg);font-size:16px;line-height:1.5}*{box-sizing:border-box}html,body,#root{min-height:100svh}body{background:radial-gradient(1200px 500px at 10% -10%, #1a2a44 0%, transparent 55%), var(--bg);margin:0}a{color:var(--accent-2);text-decoration:none}a:hover{text-decoration:underline}button,.btn{font:inherit}.page{width:min(760px,100% - 32px);margin:0 auto;padding:24px 0 64px}.hero h1,.question-text,.score-big{color:var(--text);letter-spacing:-.03em}.hero h1{margin:6px 0 10px;font-size:clamp(1.8rem,4vw,2.4rem);font-weight:700}.hero.compact h1{margin-bottom:6px;font-size:1.7rem}.kicker{color:var(--accent);letter-spacing:.12em;text-transform:uppercase;margin:0;font-size:.78rem;font-weight:700}.lede,.topic-blurb,.topic-meta,.lesson-meta,.hint,.score-note,.quiz-progress,.status{color:var(--muted)}.lede{max-width:40rem;margin:0}.crumb{color:var(--muted);flex-wrap:wrap;gap:8px;margin-bottom:18px;font-size:.9rem;display:flex}.crumb span:last-child{color:var(--text)}.topic-list,.lesson-list,.options,.wrong-list ol{margin:22px 0 0;padding:0;list-style:none}.topic-card,.lesson-card{background:var(--bg-elev);border:1px solid var(--line);border-radius:var(--radius);color:inherit;box-shadow:var(--shadow);align-items:flex-start;gap:14px;margin-bottom:10px;padding:16px;display:flex}.topic-card:hover,.lesson-card:hover{background:var(--bg-hover);text-decoration:none}.topic-index,.lesson-index,.opt-key{width:42px;height:42px;color:var(--accent-2);font-variant-numeric:tabular-nums;background:#203049;border-radius:10px;flex:none;place-items:center;font-weight:700;display:grid}.topic-body,.lesson-body{flex-direction:column;flex:1;gap:4px;min-width:0;display:flex}.topic-title,.lesson-title{font-weight:650}.bar{background:#203049;border-radius:99px;height:6px;margin-top:10px;display:block;overflow:hidden}.bar-fill{background:linear-gradient(90deg,#3d8bfd,#3ecf8e);height:100%;display:block}.pill{border:1px solid var(--line);color:var(--muted);white-space:nowrap;border-radius:999px;align-self:center;padding:4px 10px;font-size:.78rem}.pill.done{color:var(--ok);border-color:#1f6b4a}.quiz-head{margin-bottom:16px}.quiz-head .bar{margin-top:12px}.question-card{background:var(--bg-elev);border:1px solid var(--line);box-shadow:var(--shadow);border-radius:18px;padding:18px}.question-text{white-space:pre-wrap;margin:0 0 14px;font-size:1.15rem;font-weight:650}.code-block,.explain{background:var(--code);border:1px solid var(--line);font-family:var(--mono);white-space:pre-wrap;border-radius:10px;margin:0 0 16px;padding:12px 14px;font-size:.86rem;line-height:1.45;overflow:auto}.options{gap:8px;margin:0;display:grid}.option{text-align:left;border:1px solid var(--line);width:100%;color:var(--text);cursor:pointer;background:#121a24;border-radius:12px;gap:10px;padding:10px;display:flex}.option:hover:not(:disabled),.option.selected{border-color:var(--accent)}.option:disabled{cursor:default}.option.correct{border-color:var(--ok);background:var(--ok-bg)}.option.wrong{border-color:var(--bad);background:var(--bad-bg)}.opt-key{text-transform:uppercase;width:32px;height:32px;font-size:.85rem}.opt-text{white-space:pre-wrap;padding-top:4px}.feedback{border:1px solid var(--line);border-radius:12px;margin-top:16px;padding:14px}.feedback.ok{background:var(--ok-bg);border-color:#1f6b4a}.feedback.bad{background:var(--bad-bg);border-color:#7a2a32}.feedback-title{margin:0 0 8px;font-weight:700}.hint{margin:14px 0 0}.btn,.actions .btn{border:1px solid var(--line);color:var(--text);cursor:pointer;background:#203049;border-radius:10px;justify-content:center;align-items:center;padding:10px 16px;display:inline-flex}.btn.primary{background:var(--accent);color:#071018;border-color:#0000;font-weight:700}.btn:hover{filter:brightness(1.08);text-decoration:none}.actions{flex-wrap:wrap;gap:10px;margin-top:22px;display:flex}.score-card{background:var(--bg-elev);border:1px solid var(--line);text-align:center;border-radius:18px;padding:22px}.score-big{margin:0;font-size:3rem;font-weight:800}.score-pct{color:var(--accent-2);margin:0;font-weight:700}.wrong-list{margin-top:22px}.wrong-list h2{margin:0 0 8px;font-size:1.05rem}.wrong-list li{border-bottom:1px solid var(--line);padding:8px 0}.status{width:min(760px,100% - 32px);margin:40px auto}.status.error{color:var(--bad)}