.contenitore {
  width: 350px;
 margin-left: auto;
 margin-right: auto;
 margin-top:50px;
 background-color: #101010;
 border-style: solid;
 border-radius: 14px;
 border-color: green;
 box-shadow: 5px 5px 5px 6px grey;
 border-width: 7px;
}
.display{
  margin-left: 85px;
  margin-right: auto;
  margin-top:10px;
  margin-bottom: 10px;
}
.pulsante{
  width: 70px;
  height: 70px;
  border-style: solid;
  border-radius: 5px;
  border-color: white;
  color: white;
  margin: 5px;
  text-align: center;
}
.tastiera{
  display: flex;
  flex-wrap: wrap;
  text-align: center;
  }

  #diviso {
    background-color: orange;
  }

  #per{
    background-color: lightblue;
  }

#meno {
  background-color: red;
}

#piu {
  background-color: violet;
}