Create a code add-on for easily adding a website to home screen on mobile.

We need some code to be created to enable a website to be added to the home screen on all mobiles with a simple pop-up. The code must have the following: - Full-screen pop-up after a time limit which is adjustable in the code. - Full-screen pop-up must have the editable background or text colors when changing the prefix in the code. - Close pop-up function and remind me later. - Remember if the pop-up has already been shown or closed. - Simple as possible to add to any website via the hosting account and code. - Work on IOS and Android / all browsers. I have an example if required.