*,*:before,*:after{box-sizing:border-box;margin:0;padding:0}:root{--sidebar-w: 240px;--topbar-h: 56px;--bg: #f4f6fb;--surface: #ffffff;--surface2: #f9fafb;--border: #e5e7eb;--text: #111827;--text-muted: #6b7280;--text-light: #9ca3af;--accent: #6c63ff;--accent-dark: #5548e0;--accent-light: #ede9ff;--green: #10b981;--green-light: #d1fae5;--yellow: #f59e0b;--yellow-light: #fef3c7;--red: #ef4444;--red-light: #fee2e2;--blue: #3b82f6;--blue-light: #dbeafe;--gray: #6b7280;--gray-light: #f3f4f6;--radius: 8px;--radius-lg: 12px;--shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.05);--shadow-md: 0 4px 6px -1px rgba(0,0,0,.1), 0 2px 4px -1px rgba(0,0,0,.06);--shadow-lg: 0 10px 15px -3px rgba(0,0,0,.1), 0 4px 6px -2px rgba(0,0,0,.05)}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text);font-size:14px;line-height:1.5}.admin-layout{display:flex;min-height:100vh}.sidebar{width:var(--sidebar-w);background:#1e2333;color:#cbd5e1;flex-shrink:0;display:flex;flex-direction:column;position:fixed;top:0;left:0;height:100vh;z-index:100}.main-area{margin-left:var(--sidebar-w);flex:1;display:flex;flex-direction:column;min-height:100vh}.topbar{height:var(--topbar-h);background:var(--surface);border-bottom:1px solid var(--border);display:flex;align-items:center;padding:0 24px;gap:16px;position:sticky;top:0;z-index:50}.page-content{flex:1;padding:28px}.sidebar-logo{padding:20px 20px 12px;border-bottom:1px solid #2d3748}.sidebar-logo h1{font-size:18px;font-weight:700;color:#f1f5f9;letter-spacing:-.3px}.sidebar-logo span{font-size:11px;color:#64748b;font-weight:500}.sidebar-nav{flex:1;padding:12px 8px;overflow-y:auto}.nav-group-label{font-size:10px;font-weight:600;color:#475569;text-transform:uppercase;letter-spacing:.8px;padding:8px 12px 4px}.nav-item{display:flex;align-items:center;gap:10px;padding:9px 12px;border-radius:var(--radius);cursor:pointer;color:#94a3b8;font-size:13.5px;font-weight:500;text-decoration:none;transition:background .15s,color .15s;margin-bottom:2px}.nav-item:hover{background:#2d3748;color:#e2e8f0}.nav-item.active{background:var(--accent);color:#fff}.nav-item svg{width:18px;height:18px;flex-shrink:0}.sidebar-footer{padding:16px;border-top:1px solid #2d3748}.sidebar-footer .user-chip{display:flex;align-items:center;gap:10px}.sidebar-footer .avatar{width:32px;height:32px;background:var(--accent);border-radius:50%;display:flex;align-items:center;justify-content:center;color:#fff;font-weight:700;font-size:13px}.sidebar-footer .user-info{font-size:12px}.sidebar-footer .user-name{color:#e2e8f0;font-weight:600}.sidebar-footer .user-role{color:#64748b}.topbar-title{font-size:16px;font-weight:600;color:var(--text)}.topbar-right{margin-left:auto;display:flex;align-items:center;gap:12px}.btn{display:inline-flex;align-items:center;gap:6px;padding:8px 16px;border-radius:var(--radius);font-size:13.5px;font-weight:500;cursor:pointer;border:none;transition:background .15s,transform .1s,box-shadow .15s;text-decoration:none}.btn:active{transform:scale(.98)}.btn-primary{background:var(--accent);color:#fff}.btn-primary:hover{background:var(--accent-dark)}.btn-secondary{background:var(--surface);color:var(--text);border:1px solid var(--border)}.btn-secondary:hover{background:var(--surface2)}.btn-danger{background:var(--red);color:#fff}.btn-danger:hover{background:#dc2626}.btn-ghost{background:transparent;color:var(--text-muted)}.btn-ghost:hover{background:var(--gray-light)}.btn-sm{padding:5px 12px;font-size:12.5px}.btn-icon{padding:7px;border-radius:var(--radius);background:transparent;color:var(--text-muted);cursor:pointer;border:none;display:inline-flex;align-items:center;justify-content:center;transition:background .15s,color .15s}.btn-icon:hover{background:var(--gray-light);color:var(--text)}.btn-icon svg{width:16px;height:16px}.card{background:var(--surface);border-radius:var(--radius-lg);border:1px solid var(--border)}.card-header{padding:16px 20px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;gap:12px}.card-header h3{font-size:15px;font-weight:600}.card-body{padding:20px}.badge{display:inline-flex;align-items:center;gap:4px;padding:3px 10px;border-radius:20px;font-size:11.5px;font-weight:600}.badge-draft{background:var(--gray-light);color:var(--gray)}.badge-review{background:var(--yellow-light);color:#92400e}.badge-published{background:var(--green-light);color:#065f46}.badge-hidden{background:#f1f5f9;color:#475569}.badge-archived{background:#f1f5f9;color:#94a3b8}.form-group{margin-bottom:16px}.form-row{display:grid;grid-template-columns:1fr 1fr;gap:16px}.form-row-3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:16px}label{display:block;font-size:12.5px;font-weight:600;color:var(--text-muted);text-transform:uppercase;letter-spacing:.4px;margin-bottom:6px}input[type=text],input[type=email],input[type=password],input[type=number],input[type=url],textarea,select{width:100%;padding:9px 12px;border:1.5px solid var(--border);border-radius:var(--radius);font-size:14px;color:var(--text);background:var(--surface);transition:border-color .15s,box-shadow .15s;outline:none;font-family:inherit}input:focus,textarea:focus,select:focus{border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-light)}textarea{resize:vertical;min-height:80px}.form-hint{font-size:11.5px;color:var(--text-muted);margin-top:4px}.tabs{display:flex;gap:4px;border-bottom:2px solid var(--border);margin-bottom:24px}.tab{padding:10px 18px;font-size:13.5px;font-weight:500;color:var(--text-muted);cursor:pointer;border-bottom:2px solid transparent;margin-bottom:-2px;transition:color .15s,border-color .15s}.tab:hover{color:var(--text)}.tab.active{color:var(--accent);border-bottom-color:var(--accent);font-weight:600}.table-wrap{overflow-x:auto}table{width:100%;border-collapse:collapse}th{font-size:11.5px;font-weight:600;color:var(--text-muted);text-transform:uppercase;letter-spacing:.4px;padding:10px 14px;text-align:left;border-bottom:1px solid var(--border);background:var(--surface2)}td{padding:12px 14px;border-bottom:1px solid var(--border);font-size:13.5px}tr:last-child td{border-bottom:none}tr:hover td{background:var(--surface2)}.table-actions{display:flex;align-items:center;gap:4px;opacity:0;transition:opacity .15s}tr:hover .table-actions{opacity:1}.drag-item{display:flex;align-items:flex-start;gap:10px;padding:12px;background:var(--surface);border:1.5px solid var(--border);border-radius:var(--radius);margin-bottom:8px;cursor:default}.drag-item:hover{border-color:var(--accent);box-shadow:var(--shadow)}.drag-handle{cursor:grab;color:var(--text-light);padding:2px;flex-shrink:0}.drag-handle:active{cursor:grabbing}.modal-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:#00000080;z-index:200;display:flex;align-items:center;justify-content:center;padding:24px}.modal{background:var(--surface);border-radius:var(--radius-lg);box-shadow:var(--shadow-lg);width:100%;max-width:640px;max-height:90vh;display:flex;flex-direction:column}.modal-lg{max-width:860px}.modal-xl{max-width:1100px}.modal-header{padding:20px 24px 16px;border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;flex-shrink:0}.modal-header h2{font-size:16px;font-weight:700}.modal-body{padding:20px 24px;overflow-y:auto}.modal-footer{padding:14px 24px;border-top:1px solid var(--border);display:flex;justify-content:flex-end;gap:10px;flex-shrink:0}.page-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:24px;gap:16px}.page-header h2{font-size:22px;font-weight:700}.page-header-actions{display:flex;gap:10px}.stats-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:16px;margin-bottom:28px}.stat-card{background:var(--surface);border-radius:var(--radius-lg);border:1px solid var(--border);padding:20px}.stat-card .stat-label{font-size:12px;font-weight:600;color:var(--text-muted);text-transform:uppercase;letter-spacing:.4px;margin-bottom:8px}.stat-card .stat-value{font-size:28px;font-weight:700;color:var(--text)}.stat-card .stat-icon{width:40px;height:40px;border-radius:var(--radius);display:flex;align-items:center;justify-content:center;margin-bottom:12px}.media-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(160px,1fr));gap:12px}.media-card{background:var(--surface);border:1.5px solid var(--border);border-radius:var(--radius);overflow:hidden;cursor:pointer;transition:border-color .15s}.media-card:hover{border-color:var(--accent)}.media-card.selected{border-color:var(--accent);box-shadow:0 0 0 2px var(--accent-light)}.media-thumb{width:100%;aspect-ratio:4/3;object-fit:cover;background:var(--bg);display:flex;align-items:center;justify-content:center;font-size:32px}.media-thumb img{width:100%;height:100%;object-fit:cover}.media-info{padding:8px 10px}.media-info .media-name{font-size:11.5px;font-weight:500;color:var(--text);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.media-info .media-type{font-size:11px;color:var(--text-muted)}.search-bar{display:flex;align-items:center;gap:8px;background:var(--surface);border:1.5px solid var(--border);border-radius:var(--radius);padding:7px 12px;transition:border-color .15s}.search-bar:focus-within{border-color:var(--accent)}.search-bar input{border:none;outline:none;font-size:13.5px;background:transparent;width:100%;color:var(--text)}.search-bar svg{color:var(--text-muted);flex-shrink:0}.tags-wrap{display:flex;flex-wrap:wrap;gap:6px;padding:6px 10px;border:1.5px solid var(--border);border-radius:var(--radius);min-height:42px;cursor:text;transition:border-color .15s}.tags-wrap:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-light)}.tag-chip{display:inline-flex;align-items:center;gap:4px;background:var(--accent-light);color:var(--accent);padding:2px 8px;border-radius:20px;font-size:12px;font-weight:600}.tag-chip button{background:none;border:none;cursor:pointer;color:var(--accent);font-size:14px;line-height:1;padding:0;display:flex}.tags-wrap input{border:none;outline:none;font-size:13px;background:transparent;min-width:80px;flex:1;color:var(--text)}.toast-container{position:fixed;bottom:24px;right:24px;z-index:999;display:flex;flex-direction:column;gap:8px}.toast{background:var(--text);color:#fff;padding:12px 20px;border-radius:var(--radius);font-size:13.5px;font-weight:500;box-shadow:var(--shadow-md);animation:slideIn .2s ease}.toast-success{background:var(--green)}.toast-error{background:var(--red)}.toast-warning{background:var(--yellow);color:#1c1917}@keyframes slideIn{0%{transform:translateY(10px);opacity:0}to{transform:translateY(0);opacity:1}}.upload-area{border:2px dashed var(--border);border-radius:var(--radius);padding:24px;text-align:center;cursor:pointer;transition:border-color .15s,background .15s}.upload-area:hover{border-color:var(--accent);background:var(--accent-light)}.upload-area input[type=file]{display:none}.upload-preview{width:100%;max-height:200px;object-fit:cover;border-radius:var(--radius);margin-top:10px}.qtype{display:inline-flex;align-items:center;gap:4px;padding:2px 8px;border-radius:20px;font-size:11px;font-weight:600}.qtype-single_choice{background:var(--blue-light);color:#1d4ed8}.qtype-multiple_choice{background:var(--accent-light);color:var(--accent-dark)}.qtype-matching{background:var(--yellow-light);color:#92400e}.qtype-free_text{background:var(--green-light);color:#065f46}.answer-option{display:flex;align-items:center;gap:10px;padding:10px 14px;background:var(--surface2);border:1.5px solid var(--border);border-radius:var(--radius);margin-bottom:8px}.answer-option.correct{border-color:var(--green);background:var(--green-light)}.answer-correct-toggle{width:22px;height:22px;border-radius:50%;border:2px solid var(--border);cursor:pointer;flex-shrink:0;background:transparent;display:flex;align-items:center;justify-content:center;transition:border-color .15s,background .15s}.answer-correct-toggle.active{border-color:var(--green);background:var(--green);color:#fff}.empty-state{text-align:center;padding:60px 20px;color:var(--text-muted)}.empty-state svg{width:48px;height:48px;margin-bottom:12px;opacity:.4}.empty-state h3{font-size:16px;font-weight:600;margin-bottom:6px;color:var(--text)}.empty-state p{font-size:13.5px}.cover-thumb{width:56px;height:40px;object-fit:cover;border-radius:6px;background:var(--bg)}.flex{display:flex}.flex-col{display:flex;flex-direction:column}.items-center{align-items:center}.justify-between{justify-content:space-between}.gap-2{gap:8px}.gap-3{gap:12px}.gap-4{gap:16px}.mt-4{margin-top:16px}.mt-6{margin-top:24px}.mb-4{margin-bottom:16px}.w-full{width:100%}.text-muted{color:var(--text-muted)}.text-sm{font-size:12.5px}.font-semibold{font-weight:600}.truncate{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.divider{border:none;border-top:1px solid var(--border);margin:16px 0}.danger{color:var(--red)}hr.divider{border:none;border-top:1px solid var(--border);margin:20px 0}@media (max-width: 768px){.form-row,.form-row-3{grid-template-columns:1fr}.stats-grid{grid-template-columns:repeat(2,1fr)}}.confirm-dialog{max-width:420px}.confirm-dialog .modal-body{padding:20px 24px}.confirm-icon{width:48px;height:48px;border-radius:50%;background:var(--red-light);color:var(--red);display:flex;align-items:center;justify-content:center;margin-bottom:12px}.spinner{width:20px;height:20px;border:2.5px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .7s linear infinite;display:inline-block}@keyframes spin{to{transform:rotate(360deg)}}.loading-overlay{display:flex;align-items:center;justify-content:center;padding:60px}.quiz-cover{width:80px;height:54px;object-fit:cover;border-radius:6px;background:var(--bg);flex-shrink:0}.quiz-cover-placeholder{width:80px;height:54px;border-radius:6px;background:linear-gradient(135deg,#667eea,#764ba2);display:flex;align-items:center;justify-content:center;font-size:20px;flex-shrink:0}.section-block{background:var(--surface);border:1.5px solid var(--border);border-radius:var(--radius-lg);margin-bottom:12px;overflow:hidden}.section-block-header{display:flex;align-items:center;gap:10px;padding:14px 16px;cursor:pointer}.section-block-header:hover{background:var(--surface2)}.section-block-body{border-top:1px solid var(--border);padding:16px}.section-expand-btn{margin-left:auto;color:var(--text-muted);transition:transform .2s}.section-expand-btn.open{transform:rotate(180deg)}.preview-host{background:#1a1a2e;color:#fff;border-radius:var(--radius-lg);padding:24px;min-height:400px}.preview-player{background:var(--surface2);border:1px solid var(--border);border-radius:var(--radius-lg);padding:24px}