import re

with open('tmp_header.html', 'r') as f:
    content = f.read()

new_header = '''<!-- wp:group {"style":{"spacing":{"blockGap":"0px"}}} -->
<div class="wp-block-group">
<!-- wp:site-title {"level":1,"style":{"typography":{"fontSize":"54px","lineHeight":"1.05","fontStyle":"normal","fontWeight":"700"},"color":{"text":"#316263"}}} /-->
</div>
<!-- /wp:group -->'''

content = re.sub(
    r'<!-- wp:group \{"style":\{"spacing":\{"blockGap":"0px"\}\}\}.*?<!-- /wp:group -->',
    new_header,
    content,
    count=1,
    flags=re.IGNORECASE | re.DOTALL
)

with open('tmp_header_updated.html', 'w') as f:
    f.write(content)