The animation-delay CSS property specifies when the animation should start. This lets the animation sequence begin some time after it's applied to an element.

A value of 0s, which is the default value of the property, indicates that the animation should begin as soon as it's applied. Otherwise, the value specifies an offset from the moment the animation is applied to the element; animation will begin that amount of time after being applied.

Specifying a negative value for the animation delay causes the animation to begin executing immediately. However, it will appear to have begun executing partway through its cycle. For example, if you specify -1s as the animation delay time, the animation will begin immediately but will start 1 second into the animation sequence.

[Webplatform](http://docs.webplatform.org/wiki/css/properties/animation-delay "Webplatform")
[Mozilla docs](https://developer.mozilla.org/en-US/docs/Web/CSS/animation-delay "Mozilla")
[Caniuse](http://caniuse.com/#feat=css-animation "Caniuse")