Also, does anyone have any advice about how to make the PDF less ugly.
Well, let’s start with the two-column issue. There’s a reason for it. Research has shown that the optimal line length for ease of reading is about ten to twelve words per line. You’re close to double that.
Now, two-columns isn’t the only way to address that, but it is a common one.
OK, that may not be so much about “less ugly”. <shrug>
Generally, I find it looks better to choose
either indented or block style. Using both at once is overkill. Also, if you do indent the first line of each paragraph, 1 to 3 ems or so is sufficient.
The colors in the language table make it harder to read than it needs to be. With quick scan of the text, I didn’t see a reason for the colors. In any case, information should never be communicated by color alone. Not only because of color-blind readers, but also because the colors may be lost when printed. Or they just might not come out distinct enough on a particular printer.
Those are a few initial thoughts. Overall, though, I like a clean style like what you’ve got. Also, I generally advise people to not even start thinking about format/layout until they’re happy with the content, but it seems like you are happy with the content now.
Finally, have you asked yourself, “Why PDF?” PDF is a fine format, but you should make sure that you know why you choose it over other formats.