This is a simple bug that I noticed just going through the commit logs. From what I can tell (and I haven't actually tested it), the code in revision 1.31 of includes/acp/acp_styles.php attempts to replace "\n\r" and "\r" with "\n", but that will not work as expected. The reason is that the Windows newline (which I presume is what was supposed to be represented) is actually "\r\n", not "\n\r".

So, the bottom line is, throughout that file (and possibly others), "\n\r" should probably be replaced with "\r\n".