> Instead of hardcoding colors, would it be better to use CSS instead.

I agree with you. The current source code contains hardcoded colors. I
could add an optional parameter to change the css for the cgitb.html()
function:

def html(einfo, context=5, css=_DEFAULT_CSS):
   ...

_DEFAULT_CSS would be a string with the equivalent of the hardcoded style.

For this change, I will modify the html code to replace some
deprecated tags (like big or font) by supported tags.

What do you think about it (new optional parameter and html update)?