:root {
            --primary: #4361ee;
            --primary-dark: #3a56d4;
            --secondary: #7209b7;
            --success: #4cc9f0;
            --danger: #f72585;
            --light: #f8f9fa;
            --dark: #212529;
            --gray: #6c757d;
            --gray-light: #e9ecef;
            --border-radius: 10px;
            --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --transition: all 0.3s ease;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        body {
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            color: var(--dark);
            min-height: 100vh;
            padding: 20px;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
        }

        header {
            text-align: center;
            margin-bottom: 30px;
            padding: 20px;
        }

        h1 {
            color: var(--primary);
            margin-bottom: 10px;
            font-size: 2.5rem;
        }

        .subtitle {
            color: var(--gray);
            font-size: 1.1rem;
        }

        .card {
            background-color: white;
            border-radius: var(--border-radius);
            box-shadow: var(--box-shadow);
            padding: 30px;
            margin-bottom: 30px;
        }

        .upload-section {
            text-align: center;
            border: 2px dashed var(--primary);
            padding: 40px 20px;
            transition: var(--transition);
            position: relative;
            overflow: hidden;
        }

        .upload-section.dragover {
            background-color: rgba(67, 97, 238, 0.05);
            border-color: var(--secondary);
        }

        .upload-icon {
            font-size: 60px;
            color: var(--primary);
            margin-bottom: 15px;
        }

        .upload-text {
            font-size: 1.2rem;
            margin-bottom: 10px;
        }

        .file-input {
            display: none;
        }

        .file-label {
            background-color: var(--primary);
            color: white;
            padding: 12px 30px;
            border-radius: 50px;
            cursor: pointer;
            display: inline-block;
            margin: 15px 0;
            font-weight: 600;
            transition: var(--transition);
        }

        .file-label:hover {
            background-color: var(--primary-dark);
            transform: translateY(-2px);
        }

        .file-info {
            margin-top: 20px;
            padding: 15px;
            background-color: var(--gray-light);
            border-radius: var(--border-radius);
            display: none;
        }

        .file-info.show {
            display: block;
        }

        .file-details {
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            margin-bottom: 10px;
        }

        .file-name {
            font-weight: 600;
            color: var(--primary);
            word-break: break-all;
        }

        .file-size {
            color: var(--gray);
            font-size: 0.9rem;
        }

        .size-warning {
            color: var(--danger);
            font-weight: 600;
            margin-top: 10px;
            display: none;
        }

        .size-warning.show {
            display: block;
        }

        .options-section {
            margin-top: 30px;
        }

        .options-title {
            font-size: 1.3rem;
            margin-bottom: 20px;
            color: var(--primary);
            border-bottom: 2px solid var(--gray-light);
            padding-bottom: 10px;
        }

        .split-options {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 20px;
            margin-bottom: 30px;
        }

        .option {
            padding: 20px;
            border-radius: var(--border-radius);
            background-color: var(--gray-light);
            cursor: pointer;
            transition: var(--transition);
            text-align: center;
        }

        .option:hover {
            background-color: #e2e6ea;
            transform: translateY(-3px);
        }

        .option.selected {
            background-color: rgba(67, 97, 238, 0.1);
            border: 2px solid var(--primary);
        }

        .option-icon {
            font-size: 30px;
            color: var(--primary);
            margin-bottom: 10px;
        }

        .option-title {
            font-weight: 600;
            margin-bottom: 5px;
        }

        .option-desc {
            font-size: 0.9rem;
            color: var(--gray);
        }

        .custom-split {
            margin-top: 20px;
            display: none;
        }

        .custom-split.show {
            display: block;
        }

        .input-group {
            display: flex;
            align-items: center;
            margin-bottom: 15px;
        }

        .input-label {
            width: 200px;
            font-weight: 600;
        }

        .custom-input {
            flex: 1;
            padding: 12px;
            border: 1px solid #ced4da;
            border-radius: var(--border-radius);
            font-size: 1rem;
        }

        .custom-input:focus {
            outline: none;
            border-color: var(--primary);
        }

        .action-section {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-top: 30px;
        }

        .btn {
            padding: 14px 40px;
            border: none;
            border-radius: 50px;
            font-size: 1.1rem;
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
        }

        .btn-primary {
            background-color: var(--primary);
            color: white;
        }

        .btn-primary:hover:not(:disabled) {
            background-color: var(--primary-dark);
            transform: translateY(-3px);
            box-shadow: 0 6px 12px rgba(67, 97, 238, 0.2);
        }

        .btn-secondary {
            background-color: var(--gray-light);
            color: var(--dark);
        }

        .btn-secondary:hover {
            background-color: #dee2e6;
        }

        .btn:disabled {
            opacity: 0.6;
            cursor: not-allowed;
        }

        .progress-section {
            margin-top: 30px;
            display: none;
        }

        .progress-section.show {
            display: block;
        }

        .progress-bar {
            height: 20px;
            background-color: var(--gray-light);
            border-radius: 10px;
            overflow: hidden;
            margin-bottom: 10px;
        }

        .progress-fill {
            height: 100%;
            background: linear-gradient(90deg, var(--primary), var(--success));
            width: 0%;
            transition: width 0.5s ease;
        }

        .progress-text {
            text-align: center;
            font-weight: 600;
            color: var(--primary);
        }

        .results-section {
            margin-top: 30px;
            display: none;
        }

        .results-section.show {
            display: block;
        }

        .results-title {
            font-size: 1.5rem;
            margin-bottom: 20px;
            color: var(--secondary);
            text-align: center;
        }

        .results-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 20px;
        }

        .result-item {
            background-color: white;
            border-radius: var(--border-radius);
            padding: 20px;
            box-shadow: 0 3px 10px rgba(0, 0, 0, 0.08);
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        .result-info {
            flex: 1;
        }

        .result-name {
            font-weight: 600;
            margin-bottom: 5px;
            word-break: break-all;
        }

        .result-size {
            color: var(--gray);
            font-size: 0.9rem;
        }

        .download-btn {
            background-color: var(--success);
            color: white;
            border: none;
            border-radius: 5px;
            padding: 8px 16px;
            cursor: pointer;
            font-weight: 600;
            transition: var(--transition);
        }

        .download-btn:hover {
            background-color: #3ab8dd;
        }

        .security-notice {
            background-color: rgba(247, 37, 133, 0.05);
            border-left: 4px solid var(--danger);
            padding: 15px;
            margin-top: 30px;
            border-radius: 0 var(--border-radius) var(--border-radius) 0;
        }

        .security-notice h3 {
            color: var(--danger);
            margin-bottom: 5px;
        }

        .security-notice p {
            font-size: 0.9rem;
            color: var(--gray);
        }

        footer {
            text-align: center;
            margin-top: 40px;
            color: var(--gray);
            font-size: 0.9rem;
            padding: 20px;
        }

        @media (max-width: 768px) {
            .container {
                padding: 10px;
            }
            
            h1 {
                font-size: 2rem;
            }
            
            .card {
                padding: 20px;
            }
            
            .split-options {
                grid-template-columns: 1fr;
            }
            
            .action-section {
                flex-direction: column;
            }
            
            .btn {
                width: 100%;
            }
            
            .input-group {
                flex-direction: column;
                align-items: flex-start;
            }
            
            .input-label {
                width: 100%;
                margin-bottom: 5px;
            }
        }