* { margin: 0; padding: 0; box-sizing: border-box; }
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
        }
        .container {
            max-width: 900px;
            margin: 0 auto;
            background: white;
            border-radius: 20px;
            padding: 40px;
            box-shadow: 0 20px 60px rgba(0,0,0,0.3);
        }
        h1 { font-size: 2.5rem; margin-bottom: 10px; color: #333; }
        .subtitle { color: #666; margin-bottom: 30px; border-left: 4px solid #667eea; padding-left: 15px; }
        .upload-area {
            border: 2px dashed #ddd;
            border-radius: 10px;
            padding: 40px;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s;
        }
        .upload-area:hover { border-color: #667eea; background: #f8f9ff; }
        .upload-area.drag-over { border-color: #667eea; background: #f0f2ff; }
        input[type="file"] { display: none; }
        .options {
            margin: 20px 0;
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }
        .option-group {
            flex: 1;
            min-width: 150px;
        }
        .option-group label {
            display: block;
            margin-bottom: 5px;
            font-weight: 600;
            color: #555;
        }
        select, input {
            width: 100%;
            padding: 10px;
            border: 1px solid #ddd;
            border-radius: 5px;
        }
        button {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 10px;
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s;
        }
        button:hover { transform: translateY(-2px); }
        button:disabled {
            opacity: 0.5;
            cursor: not-allowed;
        }
        .preview {
            margin-top: 20px;
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
            gap: 10px;
            max-height: 300px;
            overflow-y: auto;
            padding: 10px;
            background: #f9f9f9;
            border-radius: 10px;
        }
        .preview img {
            width: 100%;
            height: auto;
            border-radius: 5px;
            box-shadow: 0 2px 5px rgba(0,0,0,0.1);
        }
        .result {
            margin-top: 30px;
            display: none;
        }
        .download-btn {
            display: inline-block;
            background: #10b981;
            color: white;
            padding: 12px 24px;
            border-radius: 8px;
            text-decoration: none;
            margin-top: 15px;
            text-align: center;
            cursor: pointer;
            border: none;
            font-size: 1rem;
            font-weight: 600;
        }
        .footer-links {
            margin-top: 40px;
            padding-top: 20px;
            border-top: 1px solid #eee;
            text-align: center;
        }
        .footer-links a {
            color: #667eea;
            text-decoration: none;
            margin: 0 10px;
        }
        .loading {
            text-align: center;
            margin-top: 20px;
            display: none;
        }
        .spinner {
            border: 3px solid #f3f3f3;
            border-top: 3px solid #667eea;
            border-radius: 50%;
            width: 40px;
            height: 40px;
            animation: spin 1s linear infinite;
            margin: 0 auto;
        }
        .progress-bar {
            width: 100%;
            height: 6px;
            background: #e5e7eb;
            border-radius: 3px;
            overflow: hidden;
            margin-top: 10px;
        }
        .progress-fill {
            height: 100%;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            width: 0%;
            transition: width 0.3s;
        }
        @keyframes spin {
            0% { transform: rotate(0deg); }
            100% { transform: rotate(360deg); }
        }
        @media (max-width: 600px) {
            .container { padding: 20px; }
            h1 { font-size: 1.8rem; }
        }