Change the background color of a particular menu item

I was hoping to change the background color of the “Subscribe” item in the menu to red (a similar red to the one in the logo for the site).

I could probably use something like this to do it

#menu-item-786 { background: #005a8c; }

I used that for my other site to change an item’s background to blue, but I’m having trouble finding the number of the “subscribe” menu item.

https://www.thenewsdispatch.net