:root{--bg-dark: #1a1a1a;--bg-medium: #2a2a2a;--bg-light: #3a3a3a;--bg-control: #e8e8e8;--border-color: #ccc;--progress-color: #888;--progress-gradient: linear-gradient(90deg, #888 0%, #666 100%);--button-color: #999;--button-hover: #777;--button-disabled: #ccc;--text-white: #fff;--text-gray: #999;--text-error: #ff6b6b;--accent-primary: #667eea;--accent-secondary: #764ba2;--video-button-bg: linear-gradient(135deg, #2a2a2a 0%, #1a1a1a 100%);--video-button-hover: linear-gradient(135deg, #3a3a3a 0%, #2a2a2a 100%);--slide-button-bg: linear-gradient(135deg, #4a90a4 0%, #3a7a8a 100%);--slide-button-hover: linear-gradient(135deg, #5aa0b4 0%, #4a90a4 100%);--button-size: 50px;--modal-padding: 20px;--control-padding: 15px 20px;--border-radius-sm: 6px;--border-radius-md: 10px;--border-radius-lg: 12px}*{margin:0;padding:0;box-sizing:border-box}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background:var(--bg-dark);margin:0;padding:0;overflow:hidden;height:100vh}.container{width:100vw;height:100vh;display:flex;flex-direction:column;background:var(--bg-medium)}.slide-container{flex:1;background:var(--bg-dark);display:flex;align-items:center;justify-content:center;position:relative;overflow:hidden}.bottom-controls{background:var(--bg-control);padding:var(--control-padding);border-top:1px solid var(--border-color);display:flex;align-items:center;justify-content:space-between;gap:20px}.page-indicator{flex:1;position:relative;height:30px;display:flex;align-items:center;padding:0 10px;cursor:pointer}.progress-bar{position:absolute;left:10px;right:10px;height:6px;background:var(--border-color);border-radius:3px;overflow:visible}.progress-fill{position:absolute;left:0;top:0;height:100%;background:var(--progress-gradient);border-radius:3px;transition:width .3s ease}.progress-thumb{position:absolute;top:50%;transform:translate(-50%,-50%);width:16px;height:16px;background:#666;border:2px solid var(--text-white);border-radius:50%;box-shadow:0 2px 8px #0003;transition:left .3s ease;z-index:2}.progress-bar:hover .progress-thumb{width:20px;height:20px;box-shadow:0 3px 12px #0000004d}.toc-marker{position:absolute;top:50%;transform:translate(-50%,-50%);width:3px;height:12px;background:#999;border-radius:1.5px;z-index:1}.controls{display:flex;align-items:center;gap:10px}button{padding:10px 20px;font-size:14px;border:1px solid var(--button-color);border-radius:var(--border-radius-sm);cursor:pointer;background:var(--button-color);color:#fff;transition:all .2s;font-weight:500;display:flex;align-items:center;gap:6px}button .icon{width:20px;height:20px;stroke-width:2}button:hover:not(:disabled){background:var(--button-hover);border-color:var(--button-hover);transform:translateY(-1px)}button:disabled{background:var(--button-disabled);border-color:var(--button-disabled);cursor:not-allowed;opacity:.5}#pdfViewer{position:relative;display:inline-block;max-width:100%;max-height:100%}#pdfCanvas{max-width:100%;max-height:calc(100vh - 80px);width:auto;height:auto;display:block;box-shadow:0 4px 20px #00000080}.annotationLayer{position:absolute;top:0;left:0;pointer-events:none;transform-origin:0 0}.annotationLayer a,.annotationLayer div{pointer-events:auto}.message{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);text-align:center;padding:30px;font-size:18px;color:var(--text-white);background:#000c;border-radius:var(--border-radius-md)}.message.error{color:var(--text-error);font-weight:700}.modal{display:none;position:fixed;z-index:1000;left:0;top:0;width:100%;height:100%;background-color:#000000f2;opacity:0;transition:opacity .3s ease}.modal.show{display:flex;align-items:center;justify-content:center;opacity:1}.modal-close{position:absolute;top:20px;right:40px;color:#fff;font-size:40px;font-weight:700;cursor:pointer;z-index:1001;transition:color .2s}.modal-close:hover{color:var(--border-color)}.modal-content{position:relative;width:90vw;height:90vh}.modal-content iframe{width:100%;height:100%;border:none;border-radius:var(--border-radius-md)}.modal-content video{display:none;width:100%;height:100%;max-width:100%;max-height:100%;object-fit:contain;border-radius:var(--border-radius-md);background:#000}.toc-content{background:var(--bg-medium);border-radius:var(--border-radius-md);padding:30px;max-width:600px;max-height:80vh;overflow-y:auto;box-shadow:0 10px 40px #00000080}.toc-content h2{color:var(--text-white);margin:0 0 20px;font-size:24px;border-bottom:2px solid var(--accent-primary);padding-bottom:10px}.toc-list{display:flex;flex-direction:column;gap:10px}.toc-item{background:var(--bg-light);border:none;padding:15px 20px;border-radius:8px;cursor:pointer;transition:all .2s;text-align:left;color:var(--text-white);font-size:16px;display:flex;align-items:center;gap:15px}.toc-item:hover{background:var(--accent-primary);transform:translate(5px)}.toc-item.current{background:var(--accent-primary);box-shadow:0 0 0 2px var(--accent-secondary)}.toc-item-page{flex-shrink:0;width:40px;height:40px;background:#ffffff1a;border-radius:50%;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:14px}.toc-item-title{flex:1}.keyboard-hint{text-align:center;color:var(--text-gray);font-size:12px;margin-top:15px}.video-buttons-container{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);display:flex;flex-direction:column;gap:15px;z-index:200;padding:20px}.video-button{background:var(--video-button-bg);color:#fff;border:none;padding:15px 30px;border-radius:var(--border-radius-lg);font-size:18px;font-weight:600;cursor:pointer;box-shadow:0 4px 15px #0006;transition:all .3s ease;display:flex;align-items:center;gap:10px;min-width:250px;justify-content:center}.video-button:hover{transform:translateY(-3px);box-shadow:0 6px 20px #0009;background:var(--video-button-hover)}.video-button:active{transform:translateY(-1px)}.video-icon{font-size:20px;display:inline-block}.slide-buttons-container{position:absolute;bottom:100px;right:20px;display:flex;flex-direction:column;gap:10px;z-index:200}.slide-button{background:var(--slide-button-bg);color:#fff;border:none;padding:12px 24px;border-radius:var(--border-radius-md);font-size:16px;font-weight:600;cursor:pointer;box-shadow:0 3px 12px #4a90a466;transition:all .3s ease;display:flex;align-items:center;gap:8px;min-width:200px;justify-content:center}.slide-button:hover{transform:translateY(-2px);box-shadow:0 5px 18px #4a90a499;background:var(--slide-button-hover)}.slide-button:active{transform:translateY(0)}.slide-icon{font-size:18px;display:inline-block}@media (max-width: 768px){.bottom-controls{flex-direction:column;padding:10px;gap:10px}.controls{width:100%;justify-content:center}button{flex:1}.video-button{min-width:200px;font-size:16px;padding:12px 24px}.slide-button{min-width:180px;font-size:14px;padding:10px 20px}}