Background color on one page - Brine (Margot) Template

Site URL: https://www.jtacustominteriors.com/contact

I have having a hard time changing the background color for one particular page of my site (https://www.jtacustominteriors.com/contact) - Brine (Margot) template

I am trying to change to #CFD8C and have tried using the code below in the custom CSS section within Design menu, but to no avail:

<style>
.Main {
background-color: #CFD8C !important;
}
</style>

I have attached a screenshot of the look Im going for (changing background color in the "site Styles" section, but this changes all pages throughout and I am just trying to change the one page.

Any ideas?

Add to Page Settings > Advanced > Header, NOT Custom CSS

<style>
.Main {
background-color: #e5e5e5 !important;
}
</style>