:root{--primary: #3380f7;--primary-dark: #2563eb;--bg: #f5f7fb;--card: #fff;--text: #1e293b;--muted: #64748b;--border: #e2e8f0;--pass: #166534;--pass-bg: #dcfce7;--fail: #991b1b;--fail-bg: #fee2e2;--radius: 12px;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,PingFang SC,Hiragino Sans GB,Microsoft YaHei,sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);line-height:1.5}code{font-size:.9em;background:#eef2ff;padding:.1em .35em;border-radius:4px}.top{display:flex;align-items:center;justify-content:space-between;padding:12px 20px;background:var(--card);border-bottom:1px solid var(--border)}.back{color:var(--primary);text-decoration:none;font-weight:600}.back:hover{text-decoration:underline}.badge{font-size:.75rem;font-weight:700;color:var(--primary);background:#dbeafe;padding:4px 10px;border-radius:999px}.shell{max-width:640px;margin:0 auto;padding:24px 16px 48px}h1{margin:0 0 8px;font-size:1.5rem}.lead{margin:0 0 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ul{margin:0;padding-left:1.2rem;font-size:.9rem;color:var(--muted)}.notes li{margin-bottom:8px}.top-nav{display:flex;gap:12px;flex:1;justify-content:center}.top-nav a{color:var(--muted);text-decoration:none;font-weight:600;font-size:.9rem}.top-nav a.active,.top-nav a:hover{color:var(--primary)}.top-nav .nav-logout{border:none;background:none;color:var(--muted);font-weight:600;font-size:.9rem;cursor:pointer;padding:0}.top-nav .nav-logout:hover{color:var(--primary)}.book-list,.lesson-list{list-style:none;margin:0;padding:0}.book-item,.lesson-list li{margin-bottom:8px}.book-link,.lesson-link{width:100%;text-align:left;padding:14px 16px;border:1px solid var(--border);border-radius:8px;background:#fff;cursor:pointer}.book-link:hover,.lesson-link:hover{border-color:var(--primary);background:#f8fbff}.book-pub,.lesson-name{display:block;font-weight:600}.book-grade,.book-isbn,.lesson-id{display:block;font-size:.85rem;color:var(--muted);margin-top:4px}.unit-block h2{font-size:1rem;margin:20px 0 10px;color:var(--muted)}.linkish{background:none;border:none;color:var(--primary);cursor:pointer;font:inherit;padding:0}.meta-line{color:var(--muted);font-size:.9rem;margin:-8px 0 16px}.summary{background:#f0f9ff;border:1px solid #bae6fd;border-radius:8px;padding:12px 14px;margin-bottom:16px;font-size:.95rem}.notice.warn{background:#fffbeb;border:1px solid #fcd34d;border-radius:8px;padding:12px 14px;margin-bottom:16px;font-size:.9rem}.notice a{color:var(--primary)}.line-row{display:flex;gap:12px;align-items:flex-start;padding:12px 0;border-bottom:1px solid var(--border)}.line-row:last-child{border-bottom:none}.line-text{flex:1;min-width:0}.line-text .en{margin:0;font-weight:600}.line-text .zh{margin:4px 0 0;font-size:.9rem;color:var(--muted)}.follow-btn{flex-shrink:0;white-space:nowrap}.type-tag{font-size:.75rem;font-weight:500;color:var(--muted)}.loading,.error-box{padding:32px 16px;text-align:center;color:var(--muted)}body.modal-open{overflow:hidden}.follow-overlay{position:fixed;top:0;right:0;bottom:0;left:0;z-index:1000;background:#0f172a73;display:flex;align-items:flex-end;justify-content:center;padding:0}.follow-sheet{width:100%;max-width:640px;max-height:92vh;overflow:auto;background:var(--card);border-radius:16px 16px 0 0;padding:16px 20px 28px;box-shadow:0 -4px 24px #0f172a26}.follow-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:12px}.follow-head h2{margin:0;font-size:1.125rem}.icon-btn{padding:6px 10px}.translation{color:var(--muted);margin:0 0 12px}.follow-result.hidden{display:none}.pass-msg{color:var(--pass);font-weight:700}.fail-msg{color:var(--fail);font-weight:700}.hint.subtle{margin-top:-8px;font-size:.85rem;color:var(--primary)}.hint.subtle[hidden]{display:none}.karaoke-target.karaoke-mode{line-height:1.6}.karaoke-unit{display:inline-block;margin-right:.2em;padding:0 2px;border-radius:4px;transition:background .1s,color .1s}.karaoke-unit.active{background:#fef08a;color:var(--text)}.review-list{list-style:none;margin:0;padding:0}.review-item{margin-bottom:10px}.review-link{width:100%;text-align:left;padding:14px 16px;border:1px solid var(--border);border-radius:8px;background:#fff;cursor:pointer}.review-link:hover{border-color:var(--primary);background:#f8fbff}.review-text{display:block;font-weight:600;margin-bottom:6px}.review-meta{display:flex;flex-wrap:wrap;gap:8px;align-items:center;font-size:.85rem;color:var(--muted)}.tag{font-size:.75rem;font-weight:700;padding:2px 8px;border-radius:999px}.tag.pass{background:var(--pass-bg);color:var(--pass)}.tag.fail{background:var(--fail-bg);color:var(--fail)}.featured-story h2{margin-top:0}.story-featured-btn{display:flex;gap:14px;align-items:flex-start;width:100%;padding:12px;border:1px solid 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var(--border);border-radius:var(--radius);background:var(--card);cursor:pointer;text-align:left}.textbook-card-btn:hover{border-color:var(--primary);background:#f8fbff}.textbook-card-icon{font-size:1.5rem;flex-shrink:0}.textbook-card-body{display:flex;flex-direction:column;gap:4px;min-width:0}.textbook-card-grade{font-size:1.05rem}.textbook-card-pub{font-size:.85rem;color:var(--muted)}.book-meta-line{display:block;font-size:.8rem;color:var(--muted)}.review-card-link{display:flex;gap:14px;align-items:flex-start}.review-thumb{font-size:1.75rem;flex-shrink:0;line-height:1.2}.review-card-body{flex:1;min-width:0}.vocab-word{color:var(--primary);font-weight:700}.grammar-item{margin-bottom:14px;padding-bottom:14px;border-bottom:1px solid var(--border)}.grammar-item:last-child{margin-bottom:0;padding-bottom:0;border-bottom:none}.grammar-rule{margin:0 0 8px;font-weight:600}.subtext{margin:4px 0 0;font-size:.85rem;color:var(--muted)}.exercise-row{margin-bottom:12px}.exercise-pairs{margin:6px 0 0;padding-left:1.2rem;font-size:.9rem;color:var(--muted)}.empty-state{padding:24px 0;text-align:center}.empty-state .btn{margin-top:16px}