import re

for file in ['index.html', 'about.html']:
    content = open(file, 'r', encoding='utf-8').read()
    if '<meta name="viewport"' not in content:
        content = content.replace('<head>', '<head>\n    <meta name="viewport" content="width=device-width, initial-scale=1.0">')
        open(file, 'w', encoding='utf-8').write(content)
        print(f'Added viewport to {file}')
    else:
        print(f'Viewport already exists in {file}')