.rectangle {
  width: 650px;
  height: 1000px;
  border: 2px solid black;
  margin: auto;
}
#ecran {
    width: 550px;
    height: 150px;
    text-align: right;
    background-color: white;
    margin-left: 50px;
    margin-top: 50px;
    font-size: 100px;
}
button{
    background-color: white;
    width: 100px;
    height: 100px;
    font-size: 75px;
    margin-left: 50px;
    margin-top: 50px;
    color: rgb(0,0,0);
}
body{
    background-color: rgb(240,240,240)
}