How can I change the bold, italic and underlined font colour using HTML code?

I have blogger site and I am currently changing its HTML code on a new template.

In an old site I had ages ago I had a set of HTML code that allowed me to change the colour of the bold, italic and underlined text, so that throughout the site, any time I used <b> </b> etc. it would not only be in bold, but be in the colour I chose... almost like a css stylesheet I guess.

Anyway, I have forgotten what the coding was - any one got any ideas?

thanks!