Hi:
What you specify in the PROC REPORT code will OVERRIDE what is in the STYLE template. The usage:
[pre]
define name / order style={background=pink};
[/pre]
is a "statement-level style override option" and if the destination for the output supports style templates (HTML, RTF and PDF), then what is in the procedure at the statement level overrides what is in the template. This is how it is possible for you to do traffic lighting through style overrides in Proc PRINT, REPORT and TABULATE.
For your other questions --
double lines for the borders
variable thickness horizontal lines
you may find some ideas here:
http://support.sas.com/rnd/base/ods/odsrtf/rtf901.html
There were some "pre-production" style elements in 9.1 that may work for you for the double lines around the table. I'm not sure that you can get variable thickness lines between the data cells. You could check with Tech Support to be sure.
cynthia