body {
    background-color: #3c3c3c;
}

/* # id */
/* . class */

.border {
    box-sizing: border-box;
    border-top: 8px solid white;
    border-left: 8px solid white;
    border-right: 8px solid white;
    border-bottom: 8px solid white;
}

#mondriaan-container {
    border: 8px solid white;
    color: white;
    width: 750px;
    height: 750px;
    margin: 0 auto;
}

.float {
    float: left;
}

.div1 {
    background-color: orange;
    width: 350px;
    height: 350px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
}

.div2 {
    background-color: red;
    width: 250px;
    height: 250px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;

}

.div3 {
    background-color: green;
    width: 150px;
    height: 250px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;

}

.div4 {
    background-color: blue;
    width: 250px;
    height: 100px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
}

.div5 {
    background-color: yellow;
    width: 150px;
    height: 100px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;
}

.div6 {
    background-color: lightgreen;
    width: 350px;
    height: 200px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;
}

.div7 {
    background-color: lightblue;
    width: 250px;
    height: 200px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;
}

.div8 {
    background-color: pink;
    width: 150px;
    height: 200px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;
}

.div9 {
    background-color: mediumpurple;
    width: 600px;
    height: 200px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;
}
.div10 {
    background-color: purple;
    width: 150px;
    height: 200px;
    border-right: 8px solid black;
    border-bottom: 8px solid black;
    box-sizing: border-box;
}