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

cross-fade()

The cross-fade() CSS function can be used to blend two or more images at a defined transparency. It can be used for many simple image manipulations, such as tinting an image with a solid color or highlighting a particular area of the page by combining an image with a radial gradient.
cross-fade() css reference