What does "These widths must be constant throughout a document" mean?

I changed the wording a bit. What I meant was, for every element labeled class "table", let's say, you will have that border throughout that element's appearance in the document. Rappo 16:04, 20 March 2006 (PST)
Um. This isn't border-bottom-width-specific behavior. This is how CSS works. I don't think we should put this information on CSS properties pages. --Nickolay 02:05, 21 March 2006 (PST)