Second CTA link in header nav - different colour

I'm looking to add a "book online" button to my header navigation, next to the existing contact us CTA button, and I'd like them to match in size and shape but be in different colours.

Please could anybody help?

Try this solution:

https://www.will-myers.com/articles/add-secondary-navigation-to-your-squarespace-71-website

Thank you very much. I think I complicated things by using the word "nav" in my question. I'm just looking to replace my current CTA button on my top left with two side-by-side buttons, for Contact Us and Book Now. 

I'm not sure your solution will work for me.

Can you share your website?

Apologies I thought it would show up. www.expressmedicals.co.uk

You just need to add a second button to the first section (much easier than adding to the header navigation!)

You have three button types, the simplest thing to do if you want two similar buttons with different colours is to match the styles, fonts and padding for two button types change the colour on one and then use them next to each other.

Given you already have your website live, I would be careful when making this change as it may affect a button on another page.

An alternative would be to duplicate that button, leaving the settings the same (except text and link) and then use CSS to change the colour of the second one.