Mobile Header/Menu Background Colour

Hello.

I’m using the Woostify Theme and it’s been great. I’m trying to make use of a Transparent Header, but due to the colour scheme of the website I have changed the Menu text colour to white so that it can be seen. However, this then means that the Navigation Menu in the Mobile and tablet versions of the website cannot be seen, since both the menu background and text are white.

Can someone help me resolve this issue? Thanks.