What's the easiest way to change the background of the page borders

[mbeale (mae)]

We’d like to change ONLY the left and right border background, but not the background behind the text. Does anyone have suggestions about what/where/how to make such a change? Thanks in advance for anything anyone can share!

[zogstrip (Régis Hanol)]

That should do it

body {
  background-color: <your color>;
}

#main-outlet {
  background-color: $secondary;
}

[mbeale (mae)]

PERFECT! Thanks @zogstrip!