Oliver, your basic problem is piling in-line styles on top of the style sheet. See Diap's first reply for the way out of the wilderness. Instead of
<p align="center"><b>INTRODUCTION</b></p>
You can use
<p class="center"><b>INTRODUCTION</b></p>
and get the exact result you are seeking.
p class calls upon the appropriate paragraph style in the style sheet.
However, I probably would have used:
<h2>Introduction</h2>
instead. If you refer to the style sheet, you'll see that that would yield a centered and italicized (and effectively boldfaced) heading half again as large as the body text, which IMHO is more desirable than all caps. Or if you want a smaller heading, you could substitute h3.