* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: Arial, sans-serif;
            background-color: #f5f5f5;
            color: #333;
            margin: 0;
            overflow: auto;
        }
        
        .container {
            display: grid;
            grid-template-columns: 350px 350px 1fr;
            grid-template-rows: auto 1fr 1fr;
            grid-template-areas:
                "header header header"
                "left-top right-top frames"
                "playback right-top frames";
            gap: 15px;
            padding: 15px;
            max-width: 1400px;
            margin: 0 auto;
            min-height: 100vh;
        }
        
        h1 {
            grid-area: header;
            text-align: center;
            margin: 0 0 10px 0;
            color: #2c3e50;
            font-size: 24px;
        }
        
        .left-panel {
            grid-area: left-top;
            display: flex;
            flex-direction: column;
            gap: 15px;
        }
        
        .playback-control {
            grid-area: playback;
        }
        
        .right-top-panel {
            grid-area: right-top;
            max-width: 400px;
        }
        
        .right-bottom-panel {
            grid-area: frames;
        }
        
        .upload-section {
            background-color: white;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.1);
            min-height: 200px;
            text-align: center;
        }
        
        .upload-area {
            border: 2px dashed #3498db;
            border-radius: 6px;
            padding: 30px;
            margin-bottom: 15px;
            cursor: pointer;
            transition: all 0.3s ease;
        }
        
        .upload-area:hover {
            border-color: #2980b9;
            background-color: #f8f9fa;
        }
        
        .upload-area.dragover {
            border-color: #27ae60;
            background-color: #e8f5e9;
        }
        
        .upload-icon {
            font-size: 36px;
            color: #3498db;
            margin-bottom: 8px;
        }
        
        #videoFile {
            display: none;
        }
        
        .controls-section {
            background-color: white;
            padding: 15px;
            border-radius: 8px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.1);
        }
        
        .control-group {
            margin-bottom: 10px;
        }
        
        .control-group label {
            display: block;
            margin-bottom: 2px;
            font-weight: bold;
            color: #555;
            font-size: 12px;
        }
        
        .control-group input,
        .control-group select {
            width: 100%;
            padding: 5px;
            border: 1px solid #ddd;
            border-radius: 4px;
            font-size: 12px;
        }
        
        .control-row {
            display: flex;
            gap: 10px;
            margin-bottom: 10px;
        }
        
        .control-row .control-group {
            flex: 1;
            margin-bottom: 0;
        }
        
        .extract-btn {
            background-color: #27ae60;
            color: white;
            border: none;
            padding: 10px 20px;
            border-radius: 4px;
            font-size: 14px;
            cursor: pointer;
            transition: background-color 0.3s ease;
            width: 100%;
            margin-top: 5px;
        }
        
        .extract-btn:hover {
            background-color: #219a52;
        }
        
        .extract-btn:disabled {
            background-color: #bdc3c7;
            cursor: not-allowed;
        }
        
        .preview-section {
            background-color: white;
            padding: 15px;
            border-radius: 8px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.1);
            display: flex;
            flex-direction: column;
        }
        
        .frames-container {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
            gap: 10px;
            margin-top: 15px;
            flex: 1;
            overflow-y: auto;
        }
        
        .frame-item {
            text-align: center;
            padding: 5px;
            background-color: white;
            border-radius: 4px;
            display: flex;
            flex-direction: column;
            margin: 5px;
            box-shadow: 0 1px 3px rgba(0,0,0,0.1);
        }
        
        .frame-image-container {
            background-image: linear-gradient(45deg, #ccc 25%, transparent 25%), 
                              linear-gradient(-45deg, #ccc 25%, transparent 25%), 
                              linear-gradient(45deg, transparent 75%, #ccc 75%), 
                              linear-gradient(-45deg, transparent 75%, #ccc 75%);
            background-size: 10px 10px;
            background-position: 0 0, 0 5px, 5px -5px, -5px 0px;
            border-radius: 4px;
            margin-bottom: 8px;
            overflow: hidden;
        }
        
        .frame-image {
            width: 100%;
            height: auto;
            border-radius: 4px;
            box-shadow: 0 1px 3px rgba(0,0,0,0.1);
        }
        
        .checkerboard-bg {
            background-image: linear-gradient(45deg, #ccc 25%, transparent 25%), 
                              linear-gradient(-45deg, #ccc 25%, transparent 25%), 
                              linear-gradient(45deg, transparent 75%, #ccc 75%), 
                              linear-gradient(-45deg, transparent 75%, #ccc 75%);
            background-size: 10px 10px;
            background-position: 0 0, 0 5px, 5px -5px, -5px 0px;
        }
        
        .frame-info {
            margin-top: 8px;
            font-size: 12px;
            color: #666;
        }
        
        .download-btn {
            margin-top: 8px;
            background-color: #3498db;
            color: white;
            border: none;
            padding: 8px 12px;
            border-radius: 4px;
            font-size: 12px;
            cursor: pointer;
            transition: background-color 0.3s ease;
        }
        
        .download-btn:hover {
            background-color: #2980b9;
        }
        
        .error-message {
            color: #e74c3c;
            margin-top: 8px;
            font-size: 12px;
        }
        
        .video-preview {
            margin-top: 15px;
            text-align: center;
        }
        
        #previewVideo {
            max-width: 100%;
            max-height: 200px;
            border-radius: 4px;
        }
        
        h3 {
            margin: 0 0 10px 0;
            color: #34495e;
            font-size: 16px;
        }
        
        .small {
            font-size: 12px;
            color: #7f8c8d;
        }
        
        @media (max-width: 768px) {
            .container {
                grid-template-columns: 1fr;
                grid-template-rows: auto auto auto auto;
                grid-template-areas:
                    "header"
                    "left-top"
                    "right-top"
                    "right-bottom";
                height: auto;
                min-height: 100vh;
                overflow-y: auto;
            }
            
            .upload-section,
            .controls-section,
            .preview-section {
                height: auto;
                min-height: 200px;
            }
            
            .frames-container {
                grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
            }
        }