Edit in JSFiddle

/*Divs*/

.base-div{
	width: 100px;
	height: 100px;
	background-color: #0e0d0e;
	margin-top: 10px;
}

.color-animation-div{
	animation-name: change-background-color;
	animation-duration: 2s;
	animation-iteration-count: infinite;
	animation-direction: alternate;
	animation-timing-function: ease;
}

.size-animation-div{
	animation: change-size 2s infinite alternate ease;
}

.size-color-animation-div{
	animation-name: change-background-color, change-size;
	animation-duration: 2s;
	animation-iteration-count: infinite;
	animation-direction: alternate;
	animation-timing-function: ease;
}

/*Animations*/

@keyframes change-background-color{
	from{
		background-color: #466886;
	}to{
		background-color: #bccddc;
	}
}

@keyframes change-size{
	0%{
		width: 100px;
		height: 100px;
	}50%{
		width: 150px;
		height: 150px;
	}100%{
		width: 200px;
		height: 200px;
	}
}
<div class="base-div color-animation-div"></div>
<div class="base-div size-animation-div"></div>
<div class="base-div size-color-animation-div"></div>