body {
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  flex-direction: column;
  background: linear-gradient(
    360deg,
    hsla(53, 69%, 90%, 0.786),
    hsl(0, 5%, 96%)
  );
}

#calculator {
  font-family: Arial, sans-serif;
  background-color: hsl(0, 0%, 15%);
  border-radius: 15px;
  overflow: hidden;
  width: 300px;
  height: 500px;
  justify-content: center;
  padding-bottom: 10px;
  padding-right: 10px;
}

#dislay,
input {
  width: 100%;
  padding: 20px;
  font-size: 5rem;
  text-align: left;
  border: none;
  background-color: hsl(0, 0%, 20%);
  color: white;
}

#keys {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 10px;
  padding: 25px;
  margin: 0 auto;
  justify-content: center;
  text-align: center;
  margin-left: 15px;
}

.title {
  max-width: 200px;
  margin: 0;
  justify-content: center;
  text-align: center;
  font-size: 50px;
  font-family: Cambria, Cochin, Georgia, Times, 'Times New Roman', serif;
  -webkit-text-stroke: 2px grey;
}

.orange {
  color: orange;
}

button {
  width: 60px;
  height: 60px;
  font-size: 2rem;
  border-radius: 50px;
  border: none;
  background-color: hsl(0, 0%, 30%);
  color: white;

  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background-color: hsl(0, 0%, 40%);
}

button:active {
  background-color: hsl(0, 0%, 50%);
}

.operator-btn {
  background-color: hsl(35, 98%, 58%);
}

.operator-btn:hover {
  background-color: hsl(35, 83%, 66%);
}

.operator-btn:active {
  background-color: hsl(35, 83%, 76%);
}

@media screen and (max-width: 500px) {
  #calculator {
    margin: 0;
    height: fit-content;
  }
  #keys {
    padding: 10px;
  }
  .title {
    font-size: 40px;
  }
  button {
    width: 60px;
    height: 60px;
    font-size: 2rem;
  }
  #dislay,
  input {
    padding: 10px;
    font-size: 3rem;
  }
}