This is meant to only target the css, whether in a stylesheet or in <style> tags. It searches for the font-weight or -style, and ignores what sgc-class it actually is.
To fix the text (my preference), I'd use:
Find:
Code:
<span class="(?:(b)old|(i)talic)">([^<>]*)</span>
Replace:
And revert it back to <b> and <i> tags.