body {
  text-align: center;
  background-color: black;
  font-family: 'Helvetica', 'Arial', sans-serif;
  font-weight: bold;
  font-size: 175%;
  color: white;
}

.display {
  width: 294px;
  height: 80px;
  margin: 0 auto;
  font-size: 200%;
  text-align: right;
}

.container {
  width: 294px;
  margin: 0 auto;
  text-align: center;
  display: grid;
  grid-template-columns: 73.5px 73.5px 73.5px 73.5px;
}

.button {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 60px;
  height: 60px;
  margin-top: 5px;
  margin-bottom: 5px;
  margin-left: 5px;
  margin-right: 5px;
  background-color: #B3B3B3;
  font-size: 125%;
  cursor: pointer;
  border: solid 3px #B3B3B3;
  border-radius: 10px;
  color: rgb(40, 40, 40);
  font-weight: lighter;
}

#expon, #chs, #invert, #clear {
  background-color: rgb(40, 40, 40);
  border-color: rgb(40, 40, 40);
  color: rgb(228, 230, 235);
  font-size: 75%;
  font-weight: bold;
}

#divide, #multiply, #minus, #plus, #enter {
  background-color: orange;
  border-color: orange;
  color: rgb(40, 40, 40);
  font-weight: bold;
}