Custom Login Page

The black hat is the logo of my site i set with my theme, now I want to change this using the YITH Custom Login plugin, but it seems like what ever i do, the hat won’t go away and change to the custom one i sent in the plugin. Do I need to use the custom css box or something?

here is the ss: https://s23.postimg.org/pxcr0q8cr/image.png