at least as far as i can tell - example:

cfp:~/src/git/bookify > prince book.html --baseurl=./lib/bookify/layouts/default/
prince: lib/bookify/layouts/style.css: warning: can't open input file: No such file or directory


cfp:~/src/git/bookify > grep style book.html
    <link rel="stylesheet" type="text/css" href="style.css" />


cfp:~/src/git/bookify > ls lib/bookify/layouts/default/style.css
lib/bookify/layouts/default/style.css

seems to go one 'dirname' too many

Note that base URLs are the full URL to the document, eg. they are a filename, not just a directory name. Try adding a filename component on the end of the path. In the future we may add a --basedir option to simplify this when working with local files.