Here’s a short post on how to achieve transition effects with CSS in your Workflow forms.  First, a couple of examples:

Another:

Try it in CodePen:

The pertinent CSS for this, converted to :hover instead of clicking the named labels:

.gaButton {
width: 80px;
height: 25px;
text-transform: uppercase;
font-family: Verdana, Serif;
font-size: 14px;
letter-spacing: .5px;
border: none;
text-align: center;
color: white;
background-color: #9c3030;
outline: none !important;
padding-bottom: 2px;
cursor: pointer;
-webkit-appearance: none;
border-radius: 0;
-moz-transition: all 300ms ease;
-webkit-transition: all 300ms ease;
-o-transition: all 300ms ease;
transition: all 300ms ease;
}

.gaButton:hover {
background-color: #4d676f;
-moz-transition: all 2s ease;
-webkit-transition: all 2s ease;
-o-transition: all 2s ease;
transition: all 2s ease;
}

The transition property is the crux of this demo.  Don’t limit your testing with this to pseudo-classes like :hover though; you can apply and swap classes with javascript functionally within your forms, which remarkably expands the possibilities for this.

Additional Reading:

Using CSS in Workflow Forms