html, body {
    height: 100%;
    width: 100%;
    padding: 0;
    margin: 0;
}

div {
    width: 50%;
    height: 50%;
    float: left;
}

#div1:active, #div2:active, #div3:active, #div4:active {
   background: #ffffff;
}

#div1 {
    background: #F79F79;
}

#div2 {
    background: #F7D08A;
}

#div3 {
    background: #E3F09B;
}

#div4 {
    background: #87B6A7;
}