The final sibling combinator selector is very similar to the adjacent sibling combinator selector. The main difference is that the component currently being selected will not really need to immediately be successful the initial component, but can seem any where soon after it. A lot more info This may help https://www.presta-addons-modules.com/en/free-modules/prestashop-popup-on-exit-page-on-browser-tab-close-event.html