The mind must be given relaxation; it will arise better and keener after resting. As rich fields must not be forced-for their productiveness, the have no rest, will quickly exhaust them constantlabor will break the vigor of the mind, but if it is released and relaxed a little while, it will recover its powers
Seneca

::backdrop

The ::backdrop CSS pseudo-element is a box the size of the viewport which is rendered immediately beneath any element being presented in fullscreen mode. This includes both elements which have been placed in fullscreen mode using the Fullscreen API and <dialog> elements.
::backdrop css reference