#container {
    background-color: #09156f; margin: 0 auto;
    width: 500px;
    height: 500px;
    margin-top: 20px;
}
.square, .square {
    width: 250px;
    height: 250px;
    display: relative;
}
#blockRed {
    background-color: #ab1818;
    position: relative;
}
#rectangle{
    width:100px;
    height:20px;
    background:#ab1818;
    position:relative;
}
#container_art {
    background-color: #DAF7DC; margin: 0 auto;
    width: 450px;
    height: 450px;
    background-image: url("images/tatemodern.jpg");
    background-position: -50px;
    margin-top: 20px;
    
}
.square_art, .circle_art {
    width: 100px;
    height: 100px;
    display: block;
}
.circle_art {
    border-radius: 50%;
}
#blockDarkBlue {
    background-color: #2F4858;
    position: relative;
}
#blockLightBlue {
    background-color: #86BBD8;
    position: relative;
}