* {
  box-sizing: border-box;
  font-family: "Poppins", sans-serif;
}

body {
  background: linear-gradient(135deg, #2c3e50, #3498db);
  height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
}

.calculator {
  background-color: #222;
  padding: 20px;
  border-radius: 20px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.3);
}

#display {
  width: 100%;
  height: 60px;
  font-size: 24px;
  text-align: right;
  border: none;
  outline: none;
  margin-bottom: 20px;
  border-radius: 10px;
  padding-right: 10px;
  background-color: #333;
  color: white;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 70px);
  grid-gap: 10px;
  justify-content: center;
}

button {
  height: 80px;
  font-size: 20px;
  border: none;
  border-radius: 10px;
  background-color: #444;
  color: white;
  cursor: pointer;
  transition: 0.2s;
}

button:hover {
  background-color: #555;
}

.operator {
  background-color: #de9115;
}

.operator:hover {
  background-color: #e67e22;
}

#equal {
  background-color: #25bc64;
  grid-row: span 2;
}

#equal:hover {
  background-color: #2ecc71;
}

.zero {
  grid-column: span 2;
}

#clear {
  background-color: #e74c3c;
}

#clear:hover {
  background-color: #c0392b;
}

#del {
  background-color: #9b59b6;
}

#del:hover {
  background-color: #775e82;
}