It's probably clear from my post, but just in case: I am so unskilled in HTML that I had heard of CSS but hadn't much of an idea what it is, why it's useful, or how to use it -- but your post prodded me to at least go look it up on Wikipedia.
My HTML editing typically consists of taking a page I've downloaded (for example, "download citation list" from the IEEE website produces a very simple HTML page with no CSS usage) and then adding some annotations for my own use. A typical thing is to add a line of text along the lines of (H3)(FONT COLOR="#FF0000")Get this from the librarian!(/FONT)(/H3). (I've here substituted parentheses for angle brackets to avoid possibly confusing the forum software.) So, for private use only, antique usage seems acceptable to me.
In any case, thank you for your post. And, FWIW, I did do a partial re-installation of NTL v6 and copied the library over into my v7 folder. I don't know whether the v7 installer in fact deleted the v6 libraries; I've been migrating to a new machine and did some cleaning up which might have caused that library to disappear, but I've got it back now.