A few weird things occured:
1) when adding a styles.jrtx file (the same one from the templates demo folder) into the master report, it totally screwed up the parts in master report in iReport "view" tab.
2) when adding a style in the subreport using this: style="Serif Node" in the report element, in the "Design" tab, I can see the style has been applied, but in "view" tab, the style seems to be lost.
1) How does the report screw up? Can you provide a picture and maybe the jrtx and jrxml files? It would be really helpfull. Thanks.
2) the jrtx files are loaded only when the report is opened. So you need to reopen the file in order for the style to be applied (this should be fixed in the future).