JSFiddle
When you click the button, you see that :active pseudoclass is triggered for the parent div. Is ther
Perhaps the simplest way of achieving what you probably really want to do is to put not put the button inside the div you don't want activated.
Here, you have a container div, which contains a background div (the equivalent of the parent div in your original example). The background div has an active state separate from the button's.
.container {
position: relative;
width: 200px;
height: 200px;
}
.background {
position: absolute;
width: 100%;
height: 100%;
border: 1px solid black;
background-color: #eee;
}
.background:active {
background-color: red;
}
button {
position: relative;
}