2018 Mustang Ecoboost Premium Convertible - Foot Well LEDs

I just purchased a 2018 Mustang Ecoboost Premium Convertible and I am looking to put in some LED strips. Ideally, these would come on when the instrument panel or headlights come on. Essentially, I want this to illuminate at night. I will dim them to a point that they will not be distracting. In order to do this, I need to tap into a wire that gets 12V when the headlights are on. Has anybody done this that you can provide some guidance? I appreciate any help (and patience) in advance. I want to figure this out before purchasing the LEDs.

Thank you