:root{--bg: #f4f6fa;--panel: #ffffff;--border: #dfe3ea;--text: #1f2430;--muted: #6b7280;--primary: #2563eb;--primary-dark: #1d4ed8;--danger: #dc2626;--ok: #16a34a;--warn: #d97706;--accent: #e94560;--radius: 8px;--sidebar-w: 300px;--topbar-h: 48px;font-family:Segoe UI,Heebo,Arial,sans-serif}*{box-sizing:border-box}html,body,#root{margin:0;height:100%;background:var(--bg);color:var(--text);font-size:14px}a{color:var(--primary);text-decoration:none}button,input,select,textarea{font:inherit;color:inherit}input,select,textarea{border:1px solid var(--border);border-radius:6px;padding:6px 8px;background:#fff;min-width:0}input:focus,select:focus,textarea:focus{outline:2px solid rgba(37,99,235,.35);border-color:var(--primary)}.muted{color:var(--muted)}.small{font-size:12px}.btn{border:1px solid var(--border);background:#fff;border-radius:6px;padding:6px 12px;cursor:pointer;line-height:1.2;white-space:nowrap}.btn:hover:not(:disabled){background:#f1f5f9}.btn:disabled{opacity:.4;cursor:default}.btn.primary{background:var(--primary);border-color:var(--primary);color:#fff}.btn.primary:hover:not(:disabled){background:var(--primary-dark)}.btn.danger{background:var(--danger);border-color:var(--danger);color:#fff}.btn.ghost{background:transparent}.btn.small{padding:4px 10px;font-size:13px}.btn.big{padding:12px 24px;font-size:16px}.btn.icon{padding:2px 6px;border-color:transparent;background:transparent;color:var(--muted);font-size:13px}.btn.icon:hover:not(:disabled){background:#e8edf5;color:var(--text)}.btn.icon.danger{color:var(--danger);background:transparent;border-color:transparent}.btn.icon.active{background:#e0e7ff;color:var(--primary)}.screen-message{padding:48px;text-align:center;color:var(--muted)}.screen-message.error{color:var(--danger)}.signin{min-height:100%;display:grid;place-items:center;background:linear-gradient(135deg,#1a1a2e,#16213e 60%,#0f3460)}.signin-card{background:var(--panel);padding:40px 48px;border-radius:14px;text-align:center;width:min(420px,90vw);box-shadow:0 20px 60px #00000059}.signin-card h1{margin:0 0 4px}.signin-card .btn{margin-top:20px;width:100%}.alert{padding:8px 12px;border-radius:6px;margin:8px 0;border:1px solid}.alert.error{background:#fef2f2;border-color:#fecaca;color:#991b1b}.alert.warn{background:#fffbeb;border-color:#fde68a;color:#92400e}.topbar{position:sticky;top:0;z-index:20;height:var(--topbar-h);display:flex;align-items:center;gap:16px;padding:0 16px;background:#1a1a2e;color:#fff}.topbar-title{font-weight:600;white-space:nowrap}.topbar .logo{color:var(--accent)}.topbar-user{margin-inline-start:auto;display:flex;align-items:center;gap:10px}.topbar-user .muted{color:#b8bcc8}.topbar .btn.ghost{color:#fff;border-color:#3b4262}.save-status{flex:1;text-align:center;font-size:13px;min-height:20px;transition:color .2s}.save-status.saving{color:#cbd5e1}.save-status.saved{color:#86efac}.save-status.error{color:#fca5a5;cursor:pointer}.spinner{display:inline-block;width:10px;height:10px;border:2px solid #cbd5e1;border-top-color:transparent;border-radius:50%;margin-inline-end:6px;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.layout{display:flex;min-height:calc(100% - var(--topbar-h))}.sidebar{width:var(--sidebar-w);flex-shrink:0;background:var(--panel);border-inline-end:1px solid var(--border);position:sticky;top:var(--topbar-h);height:calc(100vh - var(--topbar-h));display:flex;flex-direction:column}.sidebar-head{display:flex;gap:6px;padding:10px;border-bottom:1px solid var(--border)}.sidebar-head .search{flex:1}.course-list{flex:1;overflow-y:auto;padding:6px}.sidebar-foot{border-top:1px solid var(--border);padding:6px}.course-group-label{font-size:11px;text-transform:uppercase;color:var(--muted);padding:10px 8px 4px;letter-spacing:.04em}.course-item{width:100%;display:flex;align-items:center;gap:8px;padding:6px 8px;border:0;background:transparent;border-radius:6px;cursor:pointer;text-align:start}.course-item:hover{background:#f1f5f9}.course-item.active{background:#e0e7ff}.course-icon{width:22px;text-align:center}.course-text{flex:1;min-width:0;display:flex;flex-direction:column}.course-name{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.course-id{font-size:11px;color:var(--muted);text-align:start}.course-count{font-size:11px;background:#eef2f7;color:var(--muted);border-radius:10px;padding:1px 7px}.main{flex:1;min-width:0;padding:16px 20px 80px}.course-header{display:flex;align-items:flex-start;justify-content:space-between;gap:12px;margin-bottom:14px}.course-header h1{margin:0 0 2px;font-size:22px}.course-actions{display:flex;gap:6px}.empty{padding:32px;text-align:center;color:var(--muted);background:var(--panel);border:1px dashed var(--border);border-radius:var(--radius)}.lesson{background:var(--panel);border:1px solid var(--border);border-radius:var(--radius);margin-bottom:12px}.lesson-head{display:flex;align-items:center;gap:6px;padding:8px 10px;border-bottom:1px solid var(--border);background:#f8fafc;border-radius:var(--radius) var(--radius) 0 0}.lesson.collapsed .lesson-head{border-bottom:0;border-radius:var(--radius)}.lesson-title{margin:0;font-size:15px;font-weight:600;flex:1;min-width:0;cursor:default}.lesson-rename{flex:1;font-weight:600}.lesson-actions{display:flex;gap:2px}.lesson-body{padding:4px 6px 6px}.link-row-wrap.dragging{opacity:.6;z-index:5;position:relative}.link-row{display:flex;align-items:center;gap:8px;padding:4px 6px;border-radius:6px;min-height:36px}.link-row:hover{background:#f8fafc}.link-row.editing{background:#eff6ff}.drag-handle{cursor:grab;border:0;background:transparent;color:#c0c6d1;padding:0 2px;letter-spacing:-3px;touch-action:none}.drag-handle:hover{color:var(--muted)}.thumb{width:28px;height:28px;border-radius:5px;object-fit:cover;flex-shrink:0;display:inline-grid;place-items:center;background:#eef2f7}.cell{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.cell.name{flex:0 1 280px;cursor:text;padding:4px 6px;border-radius:4px}span.cell.name:hover,a.cell.url:hover{background:#e8edf5}.cell.url{flex:1 1 200px;color:var(--muted);font-size:12px;padding:4px 6px;border-radius:4px;text-align:left}input.cell{padding:4px 6px}.badge{font-size:11px;padding:2px 7px;border-radius:10px;white-space:nowrap}.badge.tag{background:#fdf2f8;color:#9d174d}.badge.tag{cursor:pointer}.badge.tag.missing{background:#fef2f2;color:#b91c1c;border:1px dashed #fca5a5}input.cell.md1{flex:0 1 150px}.quick-add input.md1{flex:0 1 170px}.badge.type{background:#eef2f7;color:var(--muted)}.badge.type.file{background:#fef3c7;color:#92400e}.badge.type.image{background:#dcfce7;color:#166534}.badge.muted-badge{background:#eef2f7;color:var(--muted);margin-inline-start:8px;font-weight:400}.row-actions{display:flex;align-items:center;gap:2px;opacity:.75}.link-row:hover .row-actions,.link-row.editing .row-actions,.catalog-row .row-actions{opacity:1}.details-btn{padding:3px 8px;font-size:12px;color:var(--primary);border-color:#c7d2fe;background:#eef2ff}.details-btn.active{background:var(--primary);color:#fff;border-color:var(--primary)}.add-bar{margin:8px 6px 4px;padding:10px 12px 12px;background:#f0f6ff;border:1px solid #c7d7f5;border-radius:8px}.add-bar-head{display:flex;align-items:center;gap:12px;margin-bottom:8px}.add-bar-title{font-weight:600;color:#1e3a8a}.seg{display:inline-flex;border:1px solid #b8c8e8;border-radius:6px;overflow:hidden;background:#fff}.seg button{border:0;background:transparent;padding:4px 12px;cursor:pointer;font-size:13px;color:var(--muted)}.seg button.on{background:var(--primary);color:#fff}.upload-progress{width:140px}.add-quick{display:grid;grid-template-columns:1.2fr 1.6fr 1fr auto;gap:10px;align-items:end}.add-quick label,.add-full label{display:flex;flex-direction:column;gap:4px;font-size:12px;color:var(--muted);min-width:0}.add-quick input,.add-quick select,.add-full input,.add-full select,.add-full textarea{font-size:14px;color:var(--text);width:100%}.url-or-file{display:flex;gap:6px;align-items:center;min-height:32px}.url-or-file input{flex:1}.file-pick{display:flex;align-items:center;min-height:32px}.file-chip{display:inline-flex;align-items:center;gap:6px;padding:4px 10px;border-radius:16px;background:#ecfdf5;border:1px solid #6ee7b7;color:#065f46;font-size:13px;max-width:100%;overflow:hidden}.file-chip b{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;max-width:260px}.chip-x{border:0;background:transparent;cursor:pointer;color:#047857;padding:0 2px}.upload-status{margin-inline-start:auto;display:inline-flex;align-items:center;gap:6px;color:#1e3a8a;font-size:13px}.add-quick>.btn{height:32px}.form-grid.three{grid-template-columns:1fr 1fr 1fr}.form-grid .span3{grid-column:1 / -1}.archive-banner{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px}.icon-picker{display:flex;flex-direction:column;gap:8px}.icon-grid{display:grid;grid-template-columns:repeat(10,1fr);gap:4px}.icon-option{border:1px solid var(--border);background:#fff;border-radius:6px;font-size:18px;padding:4px 0;cursor:pointer;line-height:1.3}.icon-option:hover{background:#f1f5f9}.icon-option.selected{border-color:var(--primary);background:#e0e7ff;box-shadow:0 0 0 2px #2563eb40}.icon-custom{display:flex;align-items:center;gap:8px}.icon-preview{font-size:26px;width:40px;height:40px;display:grid;place-items:center;background:#eef2f7;border-radius:8px}.icon-custom input{flex:1}.link-details{margin:0 6px 8px 36px;padding:12px;background:#f8fafc;border:1px solid var(--border);border-radius:6px}.form-grid{display:grid;gap:10px}.form-grid.two{grid-template-columns:1fr 1fr}.form-grid label{display:flex;flex-direction:column;gap:4px;font-size:12px;color:var(--muted)}.form-grid label input,.form-grid label select,.form-grid label textarea{font-size:14px;color:var(--text)}.form-grid .span2{grid-column:1 / -1}.file-current{font-size:13px}.details-actions{display:flex;align-items:center;gap:8px;margin-top:10px}.details-actions .muted{margin-inline-start:auto}.move-box{display:flex;align-items:center;gap:6px;margin-top:12px;padding-top:10px;border-top:1px dashed var(--border);flex-wrap:wrap}.move-label{font-weight:600}.move-box select,.move-box input{flex:1;min-width:140px}.dialog{border:0;border-radius:12px;padding:0;width:min(480px,92vw);box-shadow:0 20px 60px #0000004d}.dialog::backdrop{background:#0f172a73}.dialog-body{padding:20px;margin:0}.dialog-body h3{margin:0 0 12px}.dialog-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:16px}.catalog-row .cell.name{flex:0 1 220px}.catalog-row .cell.url{flex:0 1 180px}.catalog-row .muted.small{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}@media (max-width: 900px){.layout{flex-direction:column}.sidebar{width:100%;height:auto;max-height:40vh;position:static}.form-grid.two,.form-grid.three,.add-quick{grid-template-columns:1fr}.cell.name{flex-basis:160px}}
