*{
    box-sizing: border-box;
    margin: 0px;
}
.container{
   width: 960px;
   margin: 0 auto;
   outline: dotted red;
}
.box{
    width: 400px;
    height: 150px;
    padding: 15px;
    border: 10px;
    border-radius: 10px;
    background-color: chartreuse;
    margin: 5px auto;
}
.box2{
    width: 400px;
    height: 150px;
    padding: 20px;
    border: 30px;
    border-radius: 15px;
    background-color: aqua;
    margin: 5px auto;
}
.box3{
    width: 400px;
    height: 150px;
    padding: 20px;
    border: 30px;
    border-radius: 15px;
    background-color: khaki;
    margin: 5px auto;
}
.box4{
    width: 400px;
    height: 150px;
    padding: 20px;
    border: 30px;
    border-radius: 15px;
    background-color: darkred;
    margin: 5px auto;
}
.box5{
    width: 400px;
    height: 150px;
    padding: 20px;
    border: 30px;
    border-radius: 15px;
    background-color: salmon;
    margin: 5px auto;
}