The floating widgets can be personalized using CSS over and above the customization options provided in the settings page. You can use below CSS classes to target the specific element.
#ufw_<ID>– To select the wrapper of the button/widget box with the specific ID. Example:#ufw_3#ufw_<ID> .ufw_wb– To select the widget box#ufw_<ID> .ufw_btn– To select the button