[css3-fonts] Minor Confusions Part A

   # The use of combining diacritic marks creates many variations
   # for an underlying letterform:

I don't understand this point. The "a" is not varying underneath
the diacritics. What did you mean here?

   # If a document contains characters not supported by the
   # character maps of explicitly specified fonts, a user agent
   # may use a system font fallback procedure to locate an
   # appropriate font that does.

It took me several reads to understand what was going on in this
sentence. Maybe replace "explicitly specified fonts" with
"the CSS-specified fonts"?

   # Fallback can occur because fonts are not explicitly
   # specified or because authors fail to explicitly
   # indicate the encoding used by a document.

Fonts are always explicitly specified, because 'font-family'
always has a value, even if it's a generic family keyword.
So I don't understand the first clause.

Also don't understand the second clause. In what cases does
not explicitly indicating the document encoding trigger
fallback?

~fantasai