Hello,

Problem:

Some selectors used in the print.css file doesn't match the CSS classes declared in the HTML.

The .postbody class is used in several selectors in the print.css file but this CSS class does not exist in the two HTML files that load the stylesheet ( ucp_pm_viewmessage_print.html  and  viewtopic_print.html ).

Solution:

Replace all occurrences of postbody with post in the selectors of the print.css file, or use the CSS class postbody instead of post in both HTML files.