How can I change the color of a single 'buy now' button in the Debut theme?

Hello, I would like to make a ‘buy now’ button yellow in my navigation bar. It has to be only that one button and not all of them. I am adding a photo for reference of how it needs to look like. Thank you for your help!

Hii, @Guitareditions
Kindly share your store URL so,|
I can solve it perfectly.
Thank You.

Hi, @Guitareditions .

Thanks for your message, I would be happy to point you in the right direction for this inquiry. I would recommend reaching out to us directly through our live support as this may be something our Theme’s team can help you out with directly. You can do this by logging into your store through the Help Center, searching your question/issue, then selecting “continue” at the bottom of the page that displays the search results. Once you reach a live support advisor and explain your customization request, they should be able to double-check with our themes team if this is a change they can customize for you.

Please feel free to reach back out here with any questions you may have!

Hi! this is our url https://guitar-editions.com/

hii, @Guitareditions
Paste this code on top of them.scss file.

ul#SiteNav li:nth-child(4) a {
    background-color: yellow !important;
}

Thank You.

Thank you, it worked!