:root{--ink:#1a1a1a;--muted:#6b7280;--line:#e5e7eb;--brand:#4f46e5}*{box-sizing:border-box}body,html{margin:0;padding:0}body{font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;color:var(--ink);background:#fafafa;line-height:1.5}.wrap{max-width:860px;margin:0 auto;padding:32px 20px}h1{font-size:1.6rem;margin:0 0 6px}.muted{color:var(--muted)}.card{background:#fff;border:1px solid var(--line);border-radius:14px;padding:18px 20px;margin-top:16px}.btn{background:var(--brand);color:#fff;border:0;border-radius:10px;padding:10px 16px;font-weight:600;cursor:pointer;text-decoration:none}.btn,.pill{display:inline-block}.pill{font-size:.8rem;background:#eef2ff;color:var(--brand);border-radius:999px;padding:3px 10px}.feeder-md h2,.feeder-md h3,.feeder-md h4{color:#4338ca;margin:20px 0 6px}.feeder-md h2{font-size:1.12rem;border-bottom:2px solid #e6ebf1;padding-bottom:4px}.feeder-md p{margin:8px 0}.feeder-md ul{margin:6px 0 6px 2px;padding-left:18px}.feeder-md li{margin:3px 0}.feeder-md blockquote{margin:8px 0;padding:8px 12px;background:#f4f7fb;border-left:3px solid #4f46e5;border-radius:6px;color:#374151}.feeder-md code{background:#eef2ff;padding:1px 5px;border-radius:4px;font-size:.9em}.feeder-md strong{color:#1f2937}.workbook{color:#111;line-height:1.65}.workbook .lesson-h2,.workbook h1,.workbook h2{color:#2c3e50;font-size:1.18rem;margin:22px 0 8px;padding-bottom:4px;border-bottom:2px solid #e6ebf1}.workbook .lesson-h3,.workbook h3{color:#1f5c99;font-size:1.03rem;margin:18px 0 6px}.workbook p{margin:8px 0}.workbook em{color:#5d6d7e;font-style:italic}.workbook strong{color:#2c3e50}.workbook ol,.workbook ul{margin:8px 0 8px 22px}.workbook table{width:100%;border-collapse:collapse;margin:14px 0;font-size:.96rem}.workbook td,.workbook th{border:1px solid #d8dee9;padding:8px 11px;vertical-align:top}.workbook table tr:first-child td{background:#eef2f7}.workbook table td:only-child{background:#2c3e50;color:#fff;border-color:#2c3e50;border-radius:6px}.workbook table td:only-child em,.workbook table td:only-child strong{color:#fff}.ex-slot{margin:8px 0 16px;padding:11px 12px;background:#f4f7fb;border:1px solid #dbe4f0;border-radius:10px}.ex-input{width:100%;padding:8px;border:1px solid var(--line);border-radius:8px;font-family:inherit;font-size:.95rem}.ex-actions{display:flex;justify-content:space-between;align-items:center;margin-top:6px}.ex-grade{background:var(--brand);color:#fff;border:0;border-radius:8px;padding:6px 14px;font-weight:600;cursor:pointer}.ex-grade:disabled{opacity:.5;cursor:default}.ex-wc{color:var(--muted);font-size:.85rem}.ex-pane:not(:empty){margin-top:10px;border-top:1px solid #dbe4f0;padding-top:8px}.ex-band{font-weight:700;color:#117a65}.ex-fb{font-size:.92rem;line-height:1.55;margin-top:4px;white-space:normal}.ex-msg{font-size:.9rem;color:var(--muted)}.ex-msg.err{color:#b91c1c}