I am not 100% certain if this is applicable, but I found this document which implies that in Alberta, documents must be prepared with coloured cardstock covers (back and front), with green implying that the parties are "cross appellants".

http://www.qp.alberta.ca/documents/rules2010/Rules_vol_1.pdf
(4) Each factum must have cardstock covers, front and back, prepared as
required by rule 14.87(2) [Requirements for all documents], in the following
colours:
(a) appellants, including appellants who are cross respondents — beige or
ivory;
(b) respondents, including respondents who are cross appellants — green;
(c) intervenors — blue.
AR 41/2014 s4