:root{--bg:#f6f7f9;--fg:#1b1f24;--muted:#5d6673;--card:#fff;--border:#d9dde3;--accent:#0b5fd6;--edge:#b3bac4;--c-locked:#cfd3da;--c-open:#bcd7ff;--c-learning:#ffd9a1;--c-mastered:#a9e3b8;--ok:#1d8a3c;--ng:#c2362b;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light dark}@media (prefers-color-scheme:dark){:root{--lightningcss-light: ;--lightningcss-dark:initial;--bg:#14171b;--fg:#e8eaed;--muted:#98a1ad;--card:#1d2126;--border:#353b44;--accent:#6aa5ff;--edge:#4a525d;--c-locked:#343a42;--c-open:#28508f;--c-learning:#8a5a1f;--c-mastered:#25683a;--ok:#5fd480;--ng:#ff8a80}}*{box-sizing:border-box}html,body,#root{min-height:100%;margin:0}body{background:var(--bg);color:var(--fg);font-family:system-ui,Hiragino Sans,Yu Gothic UI,Meiryo,sans-serif;line-height:1.6}.app{max-width:960px;margin:0 auto;padding:0 16px 48px}header{flex-wrap:wrap;align-items:center;gap:16px;padding:12px 0;display:flex}h1{margin:0;font-size:1.25rem}h2{font-size:1.15rem}nav{gap:8px;display:flex}.tab{border:1px solid var(--border);background:var(--card);color:var(--fg);font:inherit;cursor:pointer;border-radius:999px;padding:8px 16px}.tab.on{background:var(--accent);border-color:var(--accent);color:#fff}button{font:inherit}button.primary{background:var(--accent);color:#fff;cursor:pointer;border:0;border-radius:10px;padding:10px 20px}button.primary.big{padding:14px 28px;font-size:1.05rem}button.primary:disabled{opacity:.5;cursor:default}button.link{color:var(--accent);cursor:pointer;background:0 0;border:0;padding:0;text-decoration:underline}.muted{color:var(--muted);font-size:.9rem}.hint{margin-top:8px}.legend{flex-wrap:wrap;align-items:center;gap:12px;margin:4px 0 8px;font-size:.9rem;display:flex}.legend-item{align-items:center;gap:6px;display:inline-flex}.legend-item i{border:1px solid var(--border);border-radius:4px;width:14px;height:14px;display:inline-block}.legend-total{color:var(--muted);margin-left:auto}.tree-scroll{border:1px solid var(--border);background:var(--card);border-radius:12px;max-height:62vh;overflow:auto}.node-id{fill:#1b1f24;opacity:.75;font-size:10px}.node-name{fill:#1b1f24;font-size:12px;font-weight:600}@media (prefers-color-scheme:dark){.node-id,.node-name{fill:#f2f4f7}}.detail{background:var(--card);border:1px solid var(--border);border-radius:12px;margin-top:12px;padding:12px 16px}.detail h3{margin:0 0 4px;font-size:1.05rem}.detail dl{margin:8px 0 12px}.detail dt{color:var(--muted);margin-top:8px;font-size:.8rem}.detail dd{margin:0}.drill{max-width:560px;margin:0 auto}.progress{background:var(--border);border-radius:3px;height:6px;overflow:hidden}.progress>div{background:var(--accent);height:100%;transition:width .2s}.stem{text-align:center;word-break:keep-all;justify-content:center;align-items:center;min-height:2.6em;margin:24px 0 28px;font-size:clamp(1.6rem,6vw,2.2rem);font-weight:700;display:flex}.choices{grid-template-rows:repeat(3,72px);grid-template-columns:1fr 1fr;gap:10px;display:grid}.choice{border:2px solid var(--border);background:var(--card);height:72px;color:var(--fg);cursor:pointer;border-radius:12px;padding:0 8px;font-size:1.15rem}.choice kbd{color:var(--muted);margin-right:6px;font-size:.75rem}.choice:disabled{cursor:default}.choice.ok{border-color:var(--ok);background:color-mix(in srgb, var(--ok) 18%, var(--card))}.choice.ng{border-color:var(--ng);background:color-mix(in srgb, var(--ng) 18%, var(--card))}.thought{background:var(--card);border:1px solid var(--border);border-left:4px solid var(--ng);border-radius:10px;margin-top:16px;padding:12px 16px}.thought p{margin:4px 0 8px}.stats{gap:12px;margin:12px 0 20px;display:flex}.stats>div{background:var(--card);border:1px solid var(--border);text-align:center;border-radius:12px;flex:1;padding:12px}.stats b{font-size:1.4rem;display:block}.stats span{color:var(--muted);font-size:.8rem}.misses{padding-left:1.2rem}