Gold challenge: Not sure how do it while only adding variables

I am new to sass/scss. The challenge wants changes that I have seen done in css before but we are to only add or change variables. Any ideas on how variables alone can accomplish these changes? Thanks

What I have is

$bg-color: coral;

.navbar {
  background: $bg-color;

Is that what is meant or is there a slicker way in scss?

Variable in SCSS are defined and set the first time they are assigned. So the bootstrap variables in the “bower_components/bootstrap/scss/bootstrap” directory (or current path to bootstrap) has a file _variables.scss that controls all the bootstrap style modules. Copy some of these properties and paste them in your application.scss file and change the values. See what happens.

On Windows the file was in tracker\bower_components\bootstrap-sass\assets\stylesheets\bootstrap\_variables.scss; the relevant variables all start with $navbar-. Set them in app.scss, by that mysterious “// bootstrap variable overrides” comment.