:root{color-scheme:light;--bg: #f7f7f8;--surface: #fff;--inset: #f7f7f8;--text: #1a1a1a;--text-2: #555;--muted: #666;--faint: #999;--line: #eee;--line-strong: #ccc;--btn: #ececef;--btn-text: #1a1a1a;--accent: #2f6fed;--accent-soft: #eaf1fd;--good: #3fbf6f;--good-strong: #1f8a4c;--bad: #e0453f;--warn: #e0a83f;--info: #3f9be0;--note-bg: #fdf6e9;--note-ink: #a86f12;--shadow: rgba(0, 0, 0, .08);--rate-again: #e0453f;--rate-hard: #e0a83f;--rate-good: #3f9be0;--rate-easy: #3fbf6f;--heat-0: #ebedf0;--heat-1: #86b6ef;--heat-2: #3987e5;--heat-3: #1c5cab;--heat-4: #0d366b;--heat-l1: 72%;--heat-l2: 56%;--heat-l3: 40%;--heat-l4: 25%;--reg-l1: 80%;--reg-l2: 66%;--reg-l3: 52%}:root[data-theme=dark]{color-scheme:dark;--bg: #121316;--surface: #1e2024;--inset: #26282d;--text: #e8e8ea;--text-2: #c2c2c8;--muted: #a3a3ab;--faint: #7d7d86;--line: #2f3136;--line-strong: #44474e;--btn: #2c2f35;--btn-text: #e8e8ea;--accent: #6e9fff;--accent-soft: #1d2b47;--good: #4cc97d;--good-strong: #3fbf6f;--bad: #ff6b61;--warn: #f0b64a;--info: #3f9be0;--note-bg: #2d2517;--note-ink: #e3b35b;--shadow: rgba(0, 0, 0, .45);--rate-again: #b8413b;--rate-hard: #a8782a;--rate-good: #2f73ad;--rate-easy: #2e8a57;--heat-0: #2a2d33;--heat-1: #184f95;--heat-2: #2a78d6;--heat-3: #6da7ec;--heat-4: #b7d3f6;--heat-l1: 34%;--heat-l2: 50%;--heat-l3: 66%;--heat-l4: 82%;--reg-l1: 30%;--reg-l2: 42%;--reg-l3: 55%}*{box-sizing:border-box}html,body,#root{height:100%;margin:0}body{font-family:-apple-system,Hiragino Sans,Noto Sans JP,sans-serif;background:var(--bg);color:var(--text)}.app{display:flex;flex-direction:column;min-height:100vh;padding-top:env(safe-area-inset-top)}.app-main{position:relative;flex:1;padding:1rem 1rem 5rem;max-width:480px;width:100%;margin:0 auto}.app-nav{position:fixed;bottom:0;left:0;right:0;display:flex;background:var(--surface);border-top:1px solid var(--line-strong);padding-bottom:env(safe-area-inset-bottom)}.app-nav a{flex:1;text-align:center;padding:.9rem 0;text-decoration:none;color:var(--muted);font-size:.85rem}.app-nav a.active{color:var(--accent);font-weight:700}.card{background:var(--surface);border-radius:12px;padding:1.25rem;box-shadow:0 1px 4px var(--shadow);margin-bottom:1rem}.hanzi{font-size:2.5rem;text-align:center;margin:.5rem 0}.pinyin{text-align:center;color:var(--muted);font-size:1.1rem}button{font-size:1rem;padding:.9rem;border-radius:8px;border:none;cursor:pointer;background:var(--btn);color:var(--btn-text)}button:disabled{opacity:.5;cursor:default}.rating-row{display:grid;grid-template-columns:repeat(4,1fr);gap:.5rem;margin-top:1rem}.rating-row button{color:#fff}.rating-again{background:var(--rate-again)}.rating-hard{background:var(--rate-hard)}.rating-good{background:var(--rate-good)}.rating-easy{background:var(--rate-easy)}input[type=text]{width:100%;font-size:1.1rem;padding:.75rem;border-radius:8px;border:1px solid var(--line-strong);background:var(--surface);color:var(--text);margin-bottom:.75rem}.stat-grid{display:grid;grid-template-columns:1fr 1fr;gap:.75rem}.stat-box{background:var(--surface);border-radius:12px;padding:1rem;text-align:center}.stat-box .value{font-size:1.8rem;font-weight:700}.stat-box .label{color:var(--muted);font-size:.85rem}.option-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:.5rem;margin-bottom:.75rem}.option-grid.meaning{grid-template-columns:1fr}.option-button{background:var(--surface);border:2px solid var(--line-strong);color:var(--text)}.option-button.selected{border-color:var(--accent);background:var(--accent-soft);color:var(--accent);font-weight:700}.feedback-correct{color:var(--good);font-weight:700}.feedback-wrong{color:var(--bad);font-weight:700}.me-link{position:absolute;top:.75rem;right:1rem;width:40px;height:40px;display:flex;align-items:center;justify-content:center;border-radius:50%;background:var(--surface);color:var(--text-2);box-shadow:0 1px 4px var(--shadow);z-index:5}.me-link img{width:100%;height:100%;border-radius:50%;object-fit:cover}.me-link:hover{color:var(--accent)}textarea,select{background:var(--surface);color:var(--text)}a{color:var(--accent)}