How animation between styles can be applied?

The animation shorthand CSS property applies an animation between styles. It is a shorthand for animation-name, animation-duration, animation-timing-function, animation-delay, animation-iteration-count, animation-direction, animation-fill-mode, and animation-play-state.

/* @keyframes duration | easing-function | delay |
iteration-count | direction | fill-mode | play-state | name */
animation: 3s ease-in 1s 2 reverse both paused slidein;

/* @keyframes name | duration | easing-function | delay */
animation: slidein 3s linear 1s;

/* @keyframes name | duration */
animation: slidein 3s;

Source: https://developer.mozilla.org/en-US/docs/Web/CSS/animation