:root{--primary: #3B82F6;--primary-dark: #2563EB;--navy: #1E293B;--navy-soft: #334155;--bg: linear-gradient(135deg, #FFF1F2 0%, #F3E8FF 100%);--bg-fallback: #FFF5F8;--card: #ffffff;--text: #1E293B;--text-soft: #475569;--muted: #64748B;--accent: #3B82F6;--accent-purple: #A78BFA;--accent-pink: #EC4899;--good: #10B981;--warn: #F59E0B;--error: #EF4444;--radius: 20px;--radius-sm: 12px;--radius-lg: 24px;--shadow: 0 4px 20px rgba(59, 130, 246, .08);--shadow-soft: 0 2px 12px rgba(30, 41, 59, .06)}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg-fallback);background-image:var(--bg);color:var(--text);-webkit-font-smoothing:antialiased}.app{max-width:430px;margin:0 auto;min-height:100vh;padding:16px 16px 96px}.topbar{position:sticky;top:0;z-index:100;display:flex;align-items:center;justify-content:space-between;gap:8px;padding:12px 16px;margin:-16px -16px 16px;background:#fffffff2;-webkit-backdrop-filter:blur(12px);backdrop-filter:blur(12px);border-bottom:1px solid rgba(148,163,184,.1);box-shadow:0 2px 8px #00000005}.iconbtn{border:1px solid rgba(148,163,184,.2);background:#fffffff2;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);border-radius:12px;min-width:38px;height:38px;font-size:16px;font-weight:800;color:var(--navy);cursor:pointer;display:inline-flex;align-items:center;justify-content:center;text-decoration:none;flex-shrink:0;transition:all .2s ease}.iconbtn:hover{background:#fff;box-shadow:0 2px 8px #3b82f626;transform:translateY(-1px)}.drawer-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#16294d73;z-index:1000}.drawer{width:min(320px,85vw);height:100%;background:#fff;padding:16px;overflow-y:auto;box-shadow:2px 0 16px #00000026}.drawer-link{display:block;padding:10px 4px;font-weight:700;color:var(--navy);text-decoration:none;border-bottom:1px solid #eef1f6}.brand{display:flex;align-items:center;gap:10px;font-weight:800;font-size:20px;color:var(--navy);text-decoration:none}.brand img{width:38px;height:38px;border-radius:12px;box-shadow:0 2px 8px #3b82f633}.brand small{display:block;font-size:11px;font-weight:500;color:var(--muted)}.lang-toggle{display:flex;gap:6px}.lang-toggle button{border:1px solid rgba(148,163,184,.2);background:#ffffffe6;border-radius:999px;padding:6px 12px;font-size:12px;font-weight:700;cursor:pointer;color:var(--muted);transition:all .2s ease}.lang-toggle button.active{background:var(--primary);color:#fff;border-color:var(--primary);box-shadow:0 2px 8px #3b82f64d}.card{background:var(--card);border-radius:var(--radius-lg);padding:22px;margin-bottom:16px;box-shadow:var(--shadow);border:1px solid rgba(255,255,255,.8)}.card h1{font-size:26px;margin:0 0 8px;color:var(--navy)}.card h2{font-size:18px;margin:0 0 8px;color:var(--navy)}.card p{color:var(--muted);line-height:1.55;margin:6px 0}.btn{display:block;width:100%;border:0;border-radius:16px;padding:16px;font-size:16px;font-weight:700;background:var(--primary);color:#fff;cursor:pointer;text-align:center;text-decoration:none;transition:all .2s ease;box-shadow:0 4px 12px #3b82f640}.btn:hover{background:var(--primary-dark);box-shadow:0 6px 16px #3b82f659;transform:translateY(-2px)}.btn.secondary{background:#f1f5f9;color:var(--navy);box-shadow:none}.btn.secondary:hover{background:#e2e8f0;transform:translateY(-1px)}.btn:disabled{opacity:.5;cursor:default;box-shadow:none;transform:none}.progressbar{height:8px;border-radius:999px;background:#f1f5f9cc;overflow:hidden;margin:12px 0}.progressbar>div{height:100%;background:linear-gradient(90deg,var(--primary),var(--good));border-radius:999px;transition:width .3s ease}.row{display:flex;align-items:center;gap:10px}.grow{flex:1}.muted{color:var(--muted);font-size:14px}.chapter-row{display:flex;gap:12px;align-items:center;padding:12px 4px;border-bottom:1px solid #eef1f6;text-decoration:none;color:inherit}.chapter-row:last-child{border-bottom:0}.badge{min-width:32px;height:32px;border-radius:999px;display:inline-flex;align-items:center;justify-content:center;font-weight:800;font-size:14px;background:#f1f5f9;color:var(--navy)}.badge.done{background:var(--good);color:#fff;box-shadow:0 2px 8px #10b9814d}.badge.current{background:var(--primary);color:#fff;box-shadow:0 2px 8px #3b82f64d}.chapter-row.done{background:linear-gradient(90deg,rgba(16,185,129,.08),transparent);border-left:4px solid var(--good);border-radius:0 16px 16px 0}.error{background:linear-gradient(135deg,#fee2e2,#fecaca);color:#991b1b;border-radius:14px;padding:14px 16px;margin-bottom:16px;border-left:4px solid var(--error);font-weight:500}.dropzone{border:2px dashed rgba(59,130,246,.3);border-radius:var(--radius);padding:32px 20px;text-align:center;color:var(--muted);background:linear-gradient(135deg,#3b82f608,#a78bfa08);cursor:pointer;transition:all .2s ease}.dropzone:hover{border-color:var(--primary);background:#3b82f60d}.tabs{display:flex;gap:8px;margin:12px 0}.tabs button{flex:1;border:0;border-radius:14px;padding:12px;font-weight:700;background:#f1f5f9cc;color:var(--text-soft);cursor:pointer;transition:all .2s ease}.tabs button:hover{background:#e2e8f0}.tabs button.active{background:var(--primary);color:#fff;box-shadow:0 2px 8px #3b82f640}ul.tidy{padding-left:20px;margin:8px 0;color:var(--text)}ul.tidy li{margin:4px 0;line-height:1.5}.takeaway{background:linear-gradient(135deg,#fef3c7,#fde68a);border-radius:14px;padding:14px 16px;margin-top:14px;border-left:4px solid var(--warn)}.material-card{display:flex;gap:12px;align-items:center;padding:10px 4px;border-bottom:1px solid #eef1f6;color:inherit}.material-card:last-child{border-bottom:0}.material-cover{width:72px;height:48px;border-radius:10px;object-fit:cover;flex-shrink:0}.material-cover.placeholder{background:linear-gradient(135deg,#e8eef7,#d5dcea);display:flex;align-items:center;justify-content:center;font-size:24px}.material-info{display:flex;flex-direction:column;gap:2px;min-width:0}.material-info strong{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}details{border:1px solid rgba(59,130,246,.15);border-radius:14px;padding:0;background:linear-gradient(135deg,#3b82f608,#a78bfa08);transition:all .2s ease}details[open]{border-color:var(--primary);background:linear-gradient(135deg,#3b82f60d,#a78bfa0d);box-shadow:0 2px 8px #3b82f61a}details summary{padding:14px 16px;cursor:pointer;font-weight:700;color:var(--navy);list-style:none;display:flex;align-items:center;gap:8px;-webkit-user-select:none;user-select:none;transition:all .2s ease}details summary::-webkit-details-marker{display:none}details summary:hover{color:var(--primary)}details summary:before{content:"▶";font-size:12px;color:var(--primary);transition:transform .2s ease}details[open] summary:before{transform:rotate(90deg)}details>div{padding:0 16px 16px}.material-header{display:flex;align-items:center;gap:14px;padding:14px;margin-bottom:16px;background:linear-gradient(135deg,#3b82f60d,#a78bfa0d);border-radius:16px;border:1px solid rgba(59,130,246,.15);transition:all .2s ease}.material-header:hover{background:linear-gradient(135deg,#3b82f614,#a78bfa14);border-color:var(--primary);transform:translateY(-1px);box-shadow:0 4px 12px #3b82f626}.material-header-cover{width:80px;height:56px;border-radius:12px;object-fit:cover;flex-shrink:0;box-shadow:0 2px 8px #0000001a}.material-header-cover-placeholder{display:none;width:80px;height:56px;border-radius:12px;background:linear-gradient(135deg,#f1f5f9,#cbd5e1);align-items:center;justify-content:center;font-size:28px;flex-shrink:0}.material-header-info{display:flex;flex-direction:column;gap:4px;min-width:0;flex:1}.material-header-badge{display:inline-block;padding:3px 8px;border-radius:6px;font-size:10px;font-weight:700;background:var(--primary);color:#fff;width:fit-content}.material-header-title{font-size:15px;font-weight:700;color:var(--navy);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}