Overriding Font CSS

Hello, trying to override the font pull down menus as the desired “font weight” is not an option. Seem to be able to find the classes, but something continues to override…
tried a variety of these commands with no luck….

#ik_fb_widget p, ik_fb_feed_item, ik_fb_facebook_link, ik_fb_item_story {
font-family: “Lato”, sans-serif;
font-weight: 300;
}

#ik_fb_widget .ik_fb_feed_item {
font-family: “Lato”, sans-serif;
font-weight: 300;
}

#ik_fb_widget .ik_fb_facebook_link {
font-family: “Lato”, sans-serif;
font-weight: 300;
}

#ik_fb_widget .ik_fb_item_story {
font-family: “Lato”, sans-serif;
font-weight: 300;
}

https://ww.wp.xz.cn/plugins/ik-facebook/