For those of us with little css experience:
css stands for Cascading Style Sheets.
http://www.w3.org/Style/CSS/Overview.en.html has a huge amount of information, including a
link to http://www.w3.org/MarkUp/Guide/Style Dave Raggett, 8th April 2002 ...short guide to styling your Web pages... with
basic named colors explanation.

Finally found moi.css under c:\Program files (x86)\moi 3.0 betaOct-25-2011 \ui. (Clicked on column header "Type"),
with file name "moi" and file type "css" .

For a slider on a new MoI script, do not believe it is necessary to mess with css at all.
May add a line or two to the EnglishStrings.txt such as " Euler spiral curvature slider label=Curvature ." (I think)