The overlay is used to show content that should be displayed above the main
content. Each overlay has a unique id. This means that no overlay can have
the same id, I cannot stress this enough. This id is then used to toggle the
The triggers of the overlay must contain the class
js-overlay-trigger and the
data-modal-target with the id of the modal that
they want to trigger.
IMPORTANT TO NOTE is that once the overlay is open, you cannot scroll
anymore on the body.