What are all those extra </font> tags doing?
Answer: One by one they're closing off mismatched opening <font> tags from elsewhere in the document, leading to a cascade of changing sizes and colors.
If you must use <font>
:: insert three pages of heated discussion ::
make sure it follows the same rules as any other inline style tag: open and close within a block-level element like, here, a header. Or do I mean heading? Same as you'd do with <i> and similar.
Validation can't hurt either.