By default, Xhanch - My Twitter will include a CSS stylesheet and generate some CSS codes.
Sometime, you may want to define your own CSS codes to your WordPress theme's CSS so you want to remove all codes related to CSS generated by this plugin.
To do that, you will need to edit xhanch-my-twitter/xhanch-my-twitter.php, find and remove/comment this code add_action('wp_print_styles', 'xmt_css');.