transition-timing-function
/*increase speed toward middle then slow to end */
animation-timing-function: ease;
/*start slow increase speed till end*/
/*You should use this ease when an object is outgoing.*/
animation-timing-function: ease-in;
/*start quick decrease speed till end*/
/*You should use this ease when an object is incoming.*/
animation-timing-function: ease-out;
animation-timing-function: ease-in-out;/*start slow, speeding up, decrease speed till end*/
animation-timing-function: linear;/*animates at an even speed.*/