:root{--bg:#fff;--fg:#171717;--muted:#666;--line:#e5e5e5;--accent:#0f172a;--error:#b91c1c;--warn-bg:#fef3c7;font-family:system-ui,-apple-system,PingFang HK,Microsoft JhengHei,Noto Sans TC,sans-serif}@media (prefers-color-scheme:dark){:root{--bg:#0a0a0a;--fg:#ededed;--muted:#a3a3a3;--line:#2a2a2a;--accent:#e5e7eb;--error:#f87171;--warn-bg:#3f2f06}}*{box-sizing:border-box}html,body{background:var(--bg);color:var(--fg);margin:0}a{color:inherit}.card{border:1px solid var(--line);border-radius:12px;max-width:420px;margin:12vh auto;padding:24px}.topbar{border-bottom:1px solid var(--line);align-items:center;gap:16px;padding:12px 20px;display:flex}.topbar nav{gap:14px;display:flex}.spacer{flex:1}.content{max-width:960px;margin:0 auto;padding:24px 20px}button{border:1px solid var(--line);color:inherit;font:inherit;cursor:pointer;background:0 0;border-radius:8px;padding:8px 14px}button.primary{background:var(--accent);color:var(--bg);border-color:var(--accent)}button:disabled{opacity:.6;cursor:default}input,select{border:1px solid var(--line);color:inherit;font:inherit;background:0 0;border-radius:8px;padding:8px 10px}table{border-collapse:collapse;width:100%;margin:12px 0 24px}th,td{text-align:left;border-bottom:1px solid var(--line);padding:8px 10px;font-size:14px}.row{gap:8px;display:flex}.muted{color:var(--muted)}.small{font-size:13px}.error{color:var(--error)}.warn{background:var(--warn-bg);border-radius:8px;padding:10px 14px}@media (max-width:640px){.topbar{flex-wrap:wrap}th:nth-child(2),td:nth-child(2){display:none}}.stack{flex-direction:column;gap:16px;display:flex}.field{border:0;flex-direction:column;gap:6px;margin:0;padding:0;font-size:14px;display:flex}.field input,.field select,.field textarea{max-width:480px}textarea,select{border:1px solid var(--line);color:inherit;font:inherit;background:0 0;border-radius:8px;padding:8px 10px}.inline{align-items:center;gap:8px;display:flex}.row.between{justify-content:space-between;align-items:center}.button{border:1px solid var(--line);border-radius:8px;padding:8px 14px;text-decoration:none;display:inline-block}.button.primary{background:var(--accent);color:var(--bg);border-color:var(--accent)}.badge{border:1px solid var(--line);border-radius:999px;padding:2px 8px;font-size:12px}.badge.ok{background:#16a34a22;border-color:#16a34a}.panel{border:1px solid var(--line);border-radius:12px;margin:16px 0;padding:16px}.panel.issue{border-color:var(--error)}.list{margin:6px 0 0;padding-left:20px}.danger{color:var(--error);border-color:var(--error)}.lesson{border:1px solid var(--line);border-radius:12px;margin:14px 0;padding:14px}.lesson-head{flex-wrap:wrap;align-items:flex-end;gap:8px;display:flex}.lesson-head label{flex-direction:column;gap:4px;font-size:13px;display:flex}.part-row{border-top:1px dashed var(--line);flex-wrap:wrap;align-items:center;gap:8px;padding:8px 0;display:flex}.part-row input[type=text]{flex:1;min-width:160px}.tag{color:var(--muted);font-size:12px}.editor{border:1px solid var(--line);border-radius:8px;max-width:720px}.editor .toolbar{border-bottom:1px solid var(--line);flex-wrap:wrap;gap:4px;padding:6px;display:flex}.tool{padding:4px 8px;font-size:13px}.tool.on{background:var(--accent);color:var(--bg)}.editor-body{outline:none;min-height:140px;padding:10px 12px}.editor-body p{margin:0 0 8px}.panel{border:1px solid var(--line);border-radius:8px;margin-top:8px;padding:12px}