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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: #f5f5f5;
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    background: white;
    border-radius: 8px;
    padding: 30px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #333;
    margin-bottom: 30px;
}

.upload-section {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 20px;
    padding: 15px;
    background: #f9f9f9;
    border-radius: 6px;
}

#fileName {
    color: #666;
    font-size: 14px;
}

.btn {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    font-weight: 500;
    transition: background 0.2s;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-primary {
    background: #007bff;
    color: white;
}

.btn-primary:hover:not(:disabled) {
    background: #0056b3;
}

.btn-success {
    width: 100%;
    background: #28a745;
    color: white;
    padding: 12px;
    font-size: 16px;
}

.btn-success:hover:not(:disabled) {
    background: #1e7e34;
}

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

#outputHeader {
    background: #333;
    color: white;
    padding: 10px 15px;
    border-radius: 4px 4px 0 0;
    font-weight: 500;
}

#outputBox {
    background: #f9f9f9;
    border: 1px solid #ddd;
    border-top: none;
    border-radius: 0 0 4px 4px;
    padding: 15px;
    min-height: 150px;
    max-height: 400px;
    overflow-y: auto;
    font-family: 'Courier New', monospace;
    font-size: 13px;
    white-space: pre-wrap;
    word-wrap: break-word;
}