Edit in JSFiddle

/*Divs*/

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

.color-transition{
	transition-property: background-color;
	transition-duration: 1s;
	transition-timing-function: ease;
}

.size-transition{
	transition: width 1s ease, height 1s ease;
}

.size-color-transition{
	transition: width 1s ease, height 1s ease, background-color 1s ease;
}

/*Div pseudo-classes*/

.color-transition:hover{
	background-color: #ebc621;
	transition-property: background-color;
	transition-duration: 1s;
	transition-timing-function: ease;
}

.size-transition:hover{
	width: 200px;
	height: 200px;
	transition: width 1s ease, height 1s ease;
}

.size-color-transition:hover{
	background-color: #ebc621;
	width: 200px;
	height: 200px;
	transition: width 1s ease, height 1s ease, background-color 1s ease;
}
<div class="base-div color-transition"></div>
<div class="base-div size-transition"></div>
<div class="base-div size-color-transition"></div>
Mine hiirega kastide peale