Mobile header menu all white

Hi,

I have a site using twenty twenty three theme and on mobile the header information (on a dropdown menu) cannot be seen as the text is all white and so is the background. I can’t remember/find where the place is to change the colour. I’ve tried in changing the themes colours but I’ not having any luck. Can anyone give some advice on how to do this?

Thank you,

Mark

The page I need help with: [log in to see the link]