How to have different style files in multilingual website using Drupal?
you can do this in template.php:
you have to copt css file in themefolder/css.

    function yourtheme_preprocess_page(&amp;$vars) {
        global $language ;
        $lang_name = $language-&gt;language ;
        if ($lang_name=='en')
        drupal_add_css(path_to_theme(). '/css/en-style.css');
        elseif ($lang_name=='sp')
        drupal_add_css(path_to_theme(). '/css/style-sp.css');
        $vars['styles'] = drupal_get_css(); //  use drupal_get_css() to add new css
}


so you have one of css files related to current page language.