body {
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: rgb(201, 195, 195);
}
#calculator {
  font-family: sans-serif;
  background-color: rgb(34, 32, 32);
  border-radius: 15px;
  max-width: 500px;
  overflow: hidden;
}
#display {
  width: 100%;
  padding: 20px;
  font-size: 5rem;
  text-align: left;
  border: none;
  background-color: rgb(33, 31, 31);
  color: white;
}

#keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  padding: 25px;
}

button {
  width: 100px;
  height: 100px;
  border-radius: 50px;
  border: none;
  background-color: rgb(58, 34, 34);
  color: white;
  font-size: 3rem;
  font-weight: bold;
  cursor: pointer;
}
button:hover {
  background-color: rgb(51, 49, 49);
}
button:active {
  background-color: rgb(36, 34, 34);
}
.operator-btn {
  background-color: orange;
}
.operator-btn:hover {
  background-color: rgb(235, 190, 106);
}
.operator-btn:active {
  background-color: rgb(245, 220, 173);
}
input::placeholder{
  color: white;
}