body {
    background-color: #F5F5F5;
    color: #555;
    font-size: 1.1em;
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

hr {
    margin: 50px 0;
}

.container {
    margin: 40px auto;
    max-width: 700px;
}

.element {
    border: 1px solid #eee;
    height: 300px;
    background: url(http://tympanus.net/codrops-playground/assets/images/cssref/datatypes/calc/roses-1.jpg), url(http://tympanus.net/codrops-playground/assets/images/cssref/datatypes/calc/roses-2.jpg);
    background-repeat: no-repeat;
    background-color: white;
    background-position: calc(50% + 20px) calc(50% + 20px), 50% 50%;
}