Mobile menu color

On the main page the menu is colourful, but on the other pages it switches into black-and-white mode. How to make it colourful everywhere?

(Temporary website address http://tm-mmi.kpi.ua/temptemp )

Extra CSS code.

.sub-menu a {
	background-color: #f1d204;
	color: #fff;
	}

It does not change the color of the letters. But at least it changes the color of the menu.

Hey there

Thank you for the question
Is your problem resolved by the code you shared in the second message?
Thanks