body {
  font-family: Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  background-color: #f0f0f0;
}

.calculadora {
  background-color: #333;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
}

.pantalla {
  width: 100%;
  height: 80px;
  font-size: 2em;
  text-align: right;
  padding: 0 15px;
  margin-bottom: 15px;
  border: none;
  border-radius: 5px;
  background-color: #000;
  color: white;
  box-sizing: border-box;
}

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

.boton {
  width: 70px;
  height: 70px;
  font-size: 1.5em;
  border: none;
  border-radius: 5px;
  cursor: pointer;
  transition: background-color 0.2s;
}

.numero {
  background-color: #666;
  color: white;
}

.numero:hover {
  background-color: #777;
}

.operacion {
  background-color: #ff9500;
  color: white;
}

.operacion:hover {
  background-color: #ffad33;
}

.limpiar {
  background-color: #a6a6a6;
  color: black;
  grid-column: 3 / 4;
}

.limpiar:hover {
  background-color: #b8b8b8;
}

.cero {
  grid-column: 2 / 4;
}