CSS Code - Change the color or style of your first or last Squarespace navigation items

Site URL: https://www.facilitiescouncil.org/

Hi, 

I am trying to change the color of a navigation link. Here is the code I have been using in the Custom CSS block within Design. Why is this not working? Thanks for any help! Sean O. 

.header-nav-item
a[href='/covid19-guidance']
{color: red;}

Try adding this to Last Line in CUstom CSS Box

#main-navigation .page-collection [href*="covid19"] {
    color: red !important;
}