I've notice that the HTML & CSS for https://fosdem.org/2025/ is a little out of date.

• Wrong doctype
• Use of obsolete elements like <center>
• Metadata not compliant with modern standards
• Repeated use of <br> rather than CSS positioning
• A few minor accessibility issues around contrast
• Not mobile friendly
  

Would it be OK if I send some PRs to modernise the HTML and fix some of the issues? I would keep the same look and feel, page structure, etc.