Answer 1

Guessing it's about html stuff ( because of tag 'frames', but no sure ^^ ):
Make it in a container that you position 'fixed' on top of your page, and set to it a css 'animation' property associated to a '@keyframes' rules about animating opacity from 1 to 0...
Check this simple example: https://code.sololearn.com/WFVLBeztLI51/#html