Dump this code anywhere in Theme’s template functions.php file (For example, functions.php file for a Theme named “default” would probably reside in the directory wp-content/themes/default/functions.php):
add_filter(‘gallery_style’,
create_function(
‘$css’,
‘return preg_replace(“#<style type=\’text/css\’>(.*?)</style>#s”, “”, $css);’
)
);
And these are the classes for your stylesheet:
.gallery {}
.gallery-item {}
.gallery-icon {}
.gallery-caption {}