:root{--bg: #f6f6fb;--surface: #ffffff;--text: #17182b;--muted: #6b6d85;--border: #dcdcea;--primary: #3b3fb6;--primary-ink: #ffffff;--accent: #ff8fab;--ok: #1a9b72;--ok-bg: #dff5ec;--bad: #d93f4c;--bad-bg: #fde6e8;--locked: #c9cad8;--radius: 14px;--shadow: 0 2px 0 var(--border);color-scheme:light dark;font-family:system-ui,-apple-system,Segoe UI,Hiragino Sans,Noto Sans JP,sans-serif;-webkit-text-size-adjust:100%}@media(prefers-color-scheme:dark){:root{--bg: #101223;--surface: #1a1c33;--text: #ecebff;--muted: #9a9cbc;--border: #2d3052;--primary: #7d82ff;--primary-ink: #0d0e1e;--ok: #3fd3a0;--ok-bg: #12352b;--bad: #ff6b78;--bad-bg: #3a1820;--locked: #3a3c5c}}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);line-height:1.5}a{color:var(--primary)}button{font:inherit;color:inherit;cursor:pointer}button:disabled{cursor:default;opacity:.55}main{max-width:640px;margin:0 auto;padding:12px 16px calc(24px + env(safe-area-inset-bottom))}.centered{min-height:80dvh;display:grid;place-content:center;text-align:center;gap:16px}.muted{color:var(--muted);font-size:.9em}.topbar{display:flex;align-items:center;gap:16px;padding:8px 0 12px;font-weight:600}.topbar .brand{margin-right:auto;font-size:1.2rem}.topbar a{text-decoration:none}.goal{display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:10px;font-size:.85rem;color:var(--muted);margin-bottom:16px}.practice-card{display:block;padding:14px 16px;border-radius:var(--radius);background:var(--surface);border:2px solid var(--accent);color:var(--text);text-decoration:none;margin-bottom:16px}.tabs{display:grid;grid-template-columns:1fr 1fr;gap:4px;padding:4px;margin-bottom:16px;border-radius:var(--radius);background:var(--border)}.tabs a{padding:10px;text-align:center;border-radius:calc(var(--radius) - 4px);color:var(--muted);font-weight:600;text-decoration:none}.tabs a.active{background:var(--surface);color:var(--text)}.video-list{list-style:none;margin:0;padding:0;display:grid;gap:12px}.video-card{display:grid;grid-template-columns:128px 1fr;gap:12px;padding:10px;border:1px solid var(--border);border-radius:var(--radius);background:var(--surface);color:var(--text);text-decoration:none}.video-card img,.video-hero{width:100%;height:auto;aspect-ratio:16 / 9;object-fit:cover;border-radius:8px;background:var(--border)}.video-card h3{margin:0;font-size:.95rem;line-height:1.35;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden}.video-title{font-size:1.15rem;margin:12px 0 2px}.video-meta{display:flex;flex-direction:column;gap:4px;margin-top:6px;font-size:.8rem;color:var(--muted)}.video-meta .progress{height:8px}.level h2{font-size:1rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}.unit{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:12px 16px 20px;margin-bottom:16px}.unit h3{margin:0 0 8px;font-size:1.05rem}.path{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;align-items:center;gap:14px}.path li{display:flex;flex-direction:column;align-items:center;transform:translate(var(--offset, 0))}.node{width:64px;height:64px;border-radius:50%;display:grid;place-items:center;font-size:1.4rem;font-weight:700;text-decoration:none;color:var(--primary-ink);background:var(--primary);box-shadow:0 5px color-mix(in srgb,var(--primary) 60%,black)}.node.done{background:var(--ok);box-shadow:0 5px color-mix(in srgb,var(--ok) 60%,black)}.node.current{outline:4px solid var(--accent);outline-offset:4px;animation:pulse 1.6s ease-in-out infinite}.node.locked{background:var(--locked);box-shadow:none;color:var(--muted)}.node-label{font-size:.75rem;color:var(--muted);margin-top:6px}@keyframes pulse{50%{transform:scale(1.06)}}.credits{font-size:.75rem;color:var(--muted);text-align:center;padding:24px 0}.progress{height:14px;border-radius:999px;background:var(--border);overflow:hidden;flex:1}.progress-fill{height:100%;border-radius:999px;background:var(--ok);transition:width .3s ease}.lesson{display:flex;flex-direction:column;min-height:100dvh;padding-bottom:0}.lesson-header{display:flex;align-items:center;gap:12px;padding:4px 0 10px}.close{text-decoration:none;color:var(--muted);font-size:1.3rem}.hearts{color:var(--bad);font-weight:700}.sticky-video{position:sticky;top:0;z-index:2;background:var(--bg);padding-top:8px}.video{position:relative;aspect-ratio:16 / 9;border-radius:var(--radius);overflow:hidden;background:#000}.video-host,.video-host iframe{position:absolute;inset:0;width:100%;height:100%;border:0}.video-shield{position:absolute;inset:0;display:grid;place-items:center;padding:16px;text-align:center;color:#fff}.video-shield.covered{background:linear-gradient(135deg,#23265e,#3b3fb6)}.video-blur{position:absolute;left:0;right:0;bottom:0;height:24%;backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);background:#00000040}.exercise{flex:1;display:flex;flex-direction:column;gap:14px;padding:8px 0 16px}.prompt{font-size:1.25rem;margin:4px 0 0}.listen-bar{display:flex;gap:10px}.btn-listen{flex:1;display:flex;align-items:center;justify-content:center;gap:10px;min-height:56px;border:0;border-radius:var(--radius);background:var(--primary);color:var(--primary-ink);font-weight:700;font-size:1.1rem;box-shadow:0 4px color-mix(in srgb,var(--primary) 60%,black)}.btn-small,.chip-play{min-width:56px;min-height:56px;border:2px solid var(--border);border-radius:var(--radius);background:var(--surface);font-size:1.1rem}.chip-play{min-height:40px;padding:0 14px;font-size:.95rem}.voices{display:flex;flex-wrap:wrap;align-items:center;gap:8px}.choices{display:grid;gap:10px}.choice,.tile{display:flex;align-items:center;gap:12px;min-height:56px;padding:10px 14px;text-align:left;border:2px solid var(--border);border-radius:var(--radius);background:var(--surface);box-shadow:var(--shadow);font-size:1.05rem}.choice kbd{font:inherit;font-size:.75rem;color:var(--muted);border:1px solid var(--border);border-radius:6px;padding:0 6px}.choice-text{display:flex;flex-direction:column}.choice.selected,.tile.selected{border-color:var(--primary);background:color-mix(in srgb,var(--primary) 12%,var(--surface))}.tile.matched{border-color:var(--ok);background:var(--ok-bg)}.tile.wrong{border-color:var(--bad);background:var(--bad-bg);animation:shake .3s}@keyframes shake{25%{transform:translate(-4px)}75%{transform:translate(4px)}}.romaji{color:var(--muted);font-size:.85em}.spoken{display:inline-flex;flex-direction:column}.romaji-main{font-size:1.15rem;font-weight:600}.romaji-main.big{font-size:1.9rem}.ja-hint{font-size:.85rem;color:var(--muted)}.unit-title{display:inline-flex;flex-direction:column}.unit-title .romaji{font-weight:400}.match-reveal{display:flex;gap:8px;align-items:baseline}.ja{font-size:1.25rem}.ja.big{font-size:2rem;font-weight:700}rt{font-size:.55em;color:var(--muted)}.blank{display:inline-block;min-width:3em;border-bottom:3px solid var(--primary);margin:0 4px}.sentence{margin:0;line-height:2.2}.card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:16px;display:flex;flex-direction:column;gap:12px}.note{margin:0}.dev-note{margin:0;font-family:ui-monospace,monospace;font-size:.85rem;color:var(--muted)}.example{display:flex;gap:10px;align-items:flex-start}.answer{display:flex;flex-direction:column;gap:2px}.answer-line{display:flex;flex-direction:column;margin-bottom:6px}.en{font-weight:500}.match{display:grid;grid-template-columns:1fr 1fr;gap:10px}.match-col{display:grid;gap:10px;align-content:start}.arrange-answer{min-height:64px;display:flex;flex-wrap:wrap;gap:8px;padding:8px 0;border-bottom:2px solid var(--border)}.arrange-bank{display:flex;flex-wrap:wrap;gap:8px}.arrange-answer.vertical,.arrange-bank.vertical{flex-direction:column}.tile.placed{border-color:var(--primary)}.lesson-footer{position:sticky;bottom:0;margin:0 -16px;padding:14px 16px calc(14px + env(safe-area-inset-bottom));background:var(--bg);border-top:1px solid var(--border);display:flex;flex-direction:column;gap:12px}.lesson-footer.ok{background:var(--ok-bg)}.lesson-footer.bad{background:var(--bad-bg)}.feedback{display:flex;flex-direction:column;gap:6px;align-items:flex-start}.ok .feedback strong{color:var(--ok)}.bad .feedback strong{color:var(--bad)}.btn-primary{min-height:52px;border:0;border-radius:var(--radius);background:var(--ok);color:#fff;font-weight:700;font-size:1.05rem;letter-spacing:.02em;box-shadow:0 4px color-mix(in srgb,var(--ok) 60%,black)}.bad .btn-primary{background:var(--bad);box-shadow:0 4px color-mix(in srgb,var(--bad) 60%,black)}.btn-danger{border:2px solid var(--bad);color:var(--bad);background:transparent;border-radius:var(--radius);padding:10px 16px;margin-top:16px}.summary .stats{display:flex;gap:24px;justify-content:center}.summary .stats div{display:flex;flex-direction:column;align-items:center}.summary .stats b{font-size:1.6rem}.toggle,.field{display:flex;align-items:center;gap:12px;padding:14px 0;border-bottom:1px solid var(--border)}.toggle input{width:22px;height:22px}.field select{margin-left:auto}.dev-controls{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}.dev-row{display:grid;grid-template-columns:auto 1fr;gap:8px;padding:10px 0;border-bottom:1px solid var(--border)}.dev-row.bad{opacity:.5}.dev-text{display:flex;flex-direction:column}.dev-text code{font-size:.7rem;color:var(--muted)}.dev-nudge{grid-column:1 / -1;display:flex;gap:6px}@media(min-width:720px){.choices{grid-template-columns:1fr 1fr}}@media(prefers-reduced-motion:reduce){*{animation:none!important;transition:none!important}}