Looking at your CSS, where are you associating the font with the displayed text. The only item I see is associating it with <code> which would generally be used for a monospaced font. Perhaps adding a 'font-family: "ChomskyRegular";' to the body selector might help.
You also have an egregious error in your CSS where you have an stray } after the body selector. In several renderers, this will have your entire stylesheet unused.
Code:
body { margin: 5%; text-align: justify; font-size: medium; background-color: #FCF5E5; }
}
Please note that since you do not include an italic variant of the font, italics will either be faked or the selector will be disregarded.
There are several other errors.
You have an anchor in the nav.xhtml that has no content:
Code:
<li id="toc-li-1"><a href="text/ch001.xhtml#section"></a>
You are using center incorrectly. You could have a paragraph selector with text-align: center or add it as an inline style (blechhh...)
Code:
<center><p><em>For a more complete record, please see Great Crusade Chronology .</em></p></center>
Adding a .center selector in the stylesheet and replacing <center><p> with <p class="center"> and </p></center> with </p> would remove that error.
And, in my personal opinion, Chomsky is an ugly and unreadable font for body text. There's a reason that newpapers did not use that style of font in the body.
Anyhow, I've attached my corrected version of the epub to this message. Note that what I've done to it is strictly my personal choices other than correcting the errors that epubcheck popped up with.
I very
strongly recommend that you install the Sigil's epubcheck plugin and make use of it.