2) You use dark bg color for the mobile menu and dark grey color for the mega menu items in the Mega menu static block https://prnt.sc/qlz-aKjUDzKY
So, either use the lighter color that will be ok with white desktop bg and dark mobile bg or use white bg for the mobile menu or create a separate menu for the mobile device and don’t use mega menu static blocks for the mobile menu but simple subitems then menu items will have simple white color.
