gecko-dev/servo/tests/html/demo.css

body {
    background-color: rgb(200, 255, 255)
}

#hello {
    background-color: blue;
    color: red
}

#kitty {
    position: absolute;
    top: 200px;
    left: 100px;
    border-color: rgb(0, 0, 0);
    border-width: 10px
}

#boxa {
    position: absolute;
    top: 50px;
    left: 500px;
    width: 100px;
    height: 100px;
    background-color: rgba(255, 0, 0, 0.5)
}

#boxb {
    position: absolute;
    top: 70px;
    left: 580px;
    width: 100px;
    height: 100px;
    background-color: rgba(0, 255, 0, 0.5)
}

#boxc {
    position: absolute;
    top: 130px;
    left: 550px;
    width: 100px;
    height: 100px;
    background-color: rgba(0, 0, 255, 0.5)
}