Changing the red colour of the menu and the headers

I think this might be what you’re looking for, add to Appearance->Customize->Additional CSS

body:not(.overlay-header) .primary-menu > li > .icon, .entry-content h3 a {
	color: black !important;
}

Thank you very much for your answer. The colour of the headers in the upper and the middle part of the website have changed. However I faced another problem. The headers in the lower part of the website are still in red colour. Could you tell me what I have to do to change it to black colour?

This should cover them from what I can see

.entry-content h2, .footer-inner h2 a {
	color: black !important;
}

Good afternoon. Thank you very much for your help. Could you help me with one more issue? When I enter the website from the computer, the headers and the menu are in black colour as it is needed. However, when I enter it from my mobile phone, the colour of menu is still red. Could you tell ne how I can change it?

red

Yes, this should fix that

@media screen and (max-width: 768px) {
	.modal-menu a {
		color: black !important;
	}
}

Good afternoon. Thank you very much for your help!