* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #f0f0f0;
}

.calculator {
  background-color: white;
  border-radius: 8px;
  box-shadow: 0 0 15px rgba(0, 0, 0, 0.1);
  padding: 20px;
  width: 300px;
}

.display {
  width: 100%;
  height: 50px;
  text-align: right;
  font-size: 1.5em;
  margin-bottom: 10px;
  padding: 10px;
  border: 1px solid #ccc;
  border-radius: 5px;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.button {
  background-color: #f0f0f0;
  padding: 20px;
  font-size: 1.2em;
  border: 1px solid #ccc;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.3s;
}

.button:hover {
  background-color: #ddd;
}

.operator {
  background-color: #f9a825;
  color: white;
}

.operator:hover {
  background-color: #f57f17;
}

.equal {
  background-color: #388e3c;
  color: white;
}

.equal:hover {
  background-color: #2c6f3b;
}

button:active {
  transform: scale(0.98);
}