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

body {
    font-family: 'Cal Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #fafafa;
    color: #333;
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

.header {
    text-align: center;
    margin-bottom: 3rem;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #1a1a1a;
}

.header p {
    color: #666;
    font-size: 1.1rem;
}

.upload-section {
    margin-bottom: 2rem;
}

.upload-area {
    border: 2px dashed #ddd;
    border-radius: 12px;
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: white;
}

.upload-area:hover {
    border-color: #007acc;
    background: #f8fafc;
    transform: translateY(-2px);
}

.upload-area.dragover {
    border-color: #007acc;
    background: #e6f3ff;
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.7;
}

.upload-area p {
    color: #666;
    font-size: 1.1rem;
}

.options-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

.options-section h3 {
    margin-bottom: 1.5rem;
    color: #1a1a1a;
    font-size: 1.3rem;
}

.option-group {
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.option-group label {
    min-width: 120px;
    font-weight: 500;
    color: #555;
}

.option-group select,
.option-group input {
    flex: 1;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.option-group select:focus,
.option-group input:focus {
    outline: none;
    border-color: #007acc;
}

.process-btn,
.download-btn {
    width: 100%;
    padding: 1rem 2rem;
    background: #007acc;
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
}

.process-btn:hover,
.download-btn:hover {
    background: #005a9e;
    transform: translateY(-1px);
}

.process-btn:disabled {
    background: #ccc;
    cursor: not-allowed;
    transform: none;
}

.progress-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
    text-align: center;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: #eee;
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-fill {
    height: 100%;
    background: #007acc;
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.download-section {
    background: white;
    padding: 2rem;
    border-radius: 12px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    text-align: center;
}

.success-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.download-section p {
    margin-bottom: 1.5rem;
    color: #333;
    font-size: 1.1rem;
}

@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .option-group {
        flex-direction: column;
        align-items: stretch;
    }
    
    .option-group label {
        min-width: auto;
        margin-bottom: 0.5rem;
    }
}