Seeing as your using Mac OS X . . . go to . . .
Mozilla menu - Preferences - Composer - Cascading Style Sheets (CSS) Editing
Then uncheck the checkbox next to . . .
"Use CSS styles instead of HTML elements and attributes".
BTW, there are only a very tiny percentage of Netscape 4.x users left, so in the long term,
it would be better to cater primarily for users of 5th generation web browsers and upwards.
UserAgent: Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.4.1) Gecko/20031008
SeaMonkey = Swiss Army Knife: It's versatile, reliable, and contains useful tools.
Windows Internet Explorer = Old Swiss Cheese: Full of holes, and it stinks!