body {
  font-family: sans-serif;
  background: #e9f4ee;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.calculator {
  background: white;
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

input {
  width: 100%;
  height: 50px;
  font-size: 24px;
  margin-bottom: 10px;
  text-align: right;
  padding-right: 10px;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 60px);
  gap: 10px;
}

button {
  padding: 15px;
  font-size: 18px;
  border: none;
  border-radius: 8px;
  background: #c0e2d0;
  cursor: pointer;
}

button:hover {
  background: #a4d1b9;
}