body{
    margin: 0;
}
.container {
    width: 600px;
    height: 600px;
    background-color: beige;
    border: 6px solid black;
    margin: 0px auto;
    box-sizing: content-box;
}
header{
    background-color: darkcyan;
    color: white;
    padding: 20px;
    text-align: center;
    font-size: 2rem;
    margin: 0px;
}
.div1{width: 300px;
    height: 150px;
    background-color: darkkhaki;
    border-bottom: 6px solid black;
    border-right: 6px solid black;
    box-sizing: border-box;
}
.div2{width: 150px;
    height: 200px;
    background-color: salmon;
    border-bottom: 6px solid black;
    border-right: 6px solid black;
    box-sizing: border-box;
}
.div3{width: 150px;
    height: 250px;
    background-color: red;
    border-right: 6px solid black;
    box-sizing: border-box;
    float: left;

}
.div4 {
    width: 150px;
    height: 150px;
    background-color: steelblue;
    box-sizing: border-box;
    border-bottom: 6px solid black;
    border-top: 6px solid black;
    border-right: 6px solid black;
    float: left;


}
.div5{width: 200px;
    height: 250px;
    background-color: darkkhaki;
    box-sizing: border-box;
    border-top:  6px solid black;
    border-left: 6px solid black;
    float: right;


}
.div6{width: 100px;
    height: 250px;
    background-color:white;
    box-sizing: border-box;
    border-top: 6px solid black;
    float: right;

}
.div7{width: 150px;
    height: 150px;
    background-color: steelblue;
    box-sizing: border-box;

}
.div8{width: 300px;
    height: 100px;
    background-color: darkkhaki;
    box-sizing: border-box;
    border-right:  6px solid black;
}
.div9{margin-top: -450px;
    width: 300px;
    height: 200px;
background-color: red;
    border-top: 6px solid black;
    border-left: 6px solid black;
    box-sizing: border-box;
    float: right;
}
.div10{width: 0px;
    height:0px;
    background-color: salmon;
    box-sizing: border-box;
}