Local variable not in Marketo Smooth Sailing template

I am creating an email using the Marketo Smooth sailing template. I noticed that some of the local variables are not in the email, and I need to make edits to them.

I am having issues with the Articles module, specifically the right separator border color. There is no meta class for this variable, and when I add it, it still does not pop up as a local variable. I'm not that experienced with designing HTML emails, so I need some help.

How do I make that right separator color a variable that I can change? I'd like it to be white (#ffffff) for this specific email.

I've attached the HTML for reference. Thanks.