* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    padding: 40px;
    max-width: 800px;
    width: 100%;
}

h1 {
    font-size: 2.5em;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-align: center;
    margin-bottom: 10px;
}

.subtitle {
    text-align: center;
    color: #666;
    margin-bottom: 30px;
}

.upload-section {
    margin-bottom: 30px;
}

.upload-area {
    border: 2px dashed #ddd;
    border-radius: 10px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-area:hover {
    border-color: #667eea;
    background: #f8f9ff;
}

.upload-area.drag-over {
    border-color: #667eea;
    background: #f0f2ff;
    transform: scale(1.02);
}

.upload-icon {
    width: 60px;
    height: 60px;
    color: #667eea;
    margin-bottom: 20px;
}

.browse-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 30px;
    border-radius: 25px;
    font-size: 16px;
    cursor: pointer;
    transition: transform 0.2s;
    margin-top: 10px;
}

.browse-btn:hover {
    transform: translateY(-2px);
}

.file-list {
    margin-bottom: 30px;
}

.file-list h2 {
    color: #333;
    margin-bottom: 15px;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 10px;
    background: #f8f9fa;
    border-radius: 8px;
    margin-bottom: 8px;
}

.file-item .file-icon {
    width: 20px;
    height: 20px;
    margin-right: 10px;
    color: #666;
}

.file-item .file-name {
    flex: 1;
    color: #333;
}

.file-item .remove-btn {
    background: none;
    border: none;
    color: #e74c3c;
    cursor: pointer;
    padding: 5px;
}

.rename-options {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 20px;
    margin-bottom: 30px;
}

.option-group {
    margin-bottom: 20px;
}

.option-group label {
    display: block;
    color: #555;
    margin-bottom: 8px;
    font-weight: 500;
}

.option-group select,
.option-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 14px;
}

.method-options {
    margin-bottom: 20px;
}

.preview-section {
    margin-top: 20px;
}

.preview-section h3 {
    color: #333;
    margin-bottom: 10px;
}

.preview-list {
    max-height: 300px;
    overflow-y: auto;
    background: white;
    border-radius: 8px;
    padding: 10px;
}

.preview-item {
    display: flex;
    align-items: center;
    padding: 8px;
    border-bottom: 1px solid #eee;
}

.preview-item:last-child {
    border-bottom: none;
}

.preview-item .old-name {
    flex: 1;
    color: #666;
    text-decoration: line-through;
}

.preview-item .arrow {
    margin: 0 10px;
    color: #667eea;
}

.preview-item .new-name {
    flex: 1;
    color: #333;
    font-weight: 500;
}

.action-buttons {
    display: flex;
    gap: 10px;
    margin-top: 20px;
}

.apply-btn,
.download-btn,
.reset-btn {
    flex: 1;
    padding: 12px;
    border: none;
    border-radius: 8px;
    font-size: 16px;
    cursor: pointer;
    transition: all 0.3s;
}

.apply-btn {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.download-btn {
    background: #28a745;
    color: white;
}

.reset-btn {
    background: #6c757d;
    color: white;
}

.apply-btn:hover,
.download-btn:hover,
.reset-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
}

.features {
    background: #f8f9fa;
    border-radius: 10px;
    padding: 20px;
}

.features h3 {
    color: #333;
    margin-bottom: 15px;
}

.features ul {
    list-style: none;
}

.features li {
    color: #666;
    padding: 8px 0;
    padding-left: 25px;
    position: relative;
}

.features li::before {
    content: "✓";
    position: absolute;
    left: 0;
    color: #667eea;
    font-weight: bold;
}

.hidden {
    display: none;
}

.small {
    font-size: 0.9em;
    color: #999;
}

@media (max-width: 600px) {
    .container {
        padding: 20px;
    }
    
    h1 {
        font-size: 2em;
    }
    
    .action-buttons {
        flex-direction: column;
    }
}