As Acorn and Egg have highlighted you may need some workarounds to achieve your design.
You are welcome to take a look at this idea:
1. Place a sidebar link on your Home page (I have used a conventional mobile menu symbol).
2. Place your "X" on the sidebar layer (popup).
You can toggle between the two links to open and close the sidebar layer /popup.
3. Should you wish to have the sidebar autoload on the Home page, you need a few lines of code placed in the Page HTML head (there is likely other ways to do this also).
Any animation you want on the popup layer can be achieved BEFORE you place a link to it, or if you have created a link already, create your content and animations on the MouseOff layer (or any layer that does not have link), then copy and paste to the sidebar popup.
Gary
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