#clrscr {
  background-color: gray;
  margin: 0;
  padding: 10%;
  width: 50%;
  vertical-align: middle;
  text-align: center;
  color: white;
  border-radius: 10px;
  margin-bottom: 1%;
}
.cinza {
  background-color: gray;
  margin: 0;
  padding: 10%;
  width: 50%;
  vertical-align: middle;
  text-align: center;
  color: white;
  border-radius: 10px;
  margin-bottom: 1%;
}
#it {
  background-color: gray;
  margin: 0;
  padding: 10%;
  width: 50%;
  vertical-align: middle;
  text-align: center;
  color: white;
  border-radius: 10px;
  margin-bottom: 1%;
}
#sqr {
  background-color: gray;
  margin: 0;
  padding: 10%;
  width: 50%;
  vertical-align: middle;
  text-align: center;
  color: white;
  border-radius: 10px;
  margin-bottom: 1%;
}
#sqrt {
  background-color: gray;
  margin: 0;
  padding: 10%;
  width: 50%;
  vertical-align: middle;
  text-align: center;
  color: white;
  border-radius: 10px;
  margin-bottom: 1%;
}