body {
  background-color: #dbe9f4;
  font-family: Arial, sans-serif;
  text-align: center;
}

h1 {
  color: #2b4a63;
  font-size: 28px;
}

#calculadora {
  background-color: #ffffff;
  width: 240px;
  margin: 20px auto;
  padding: 15px;
  border: 3px solid #2b4a63;
  border-radius: 10px;
}

#pantalla {
  width: 95%;
  height: 40px;
  font-size: 22px;
  text-align: right;
  margin-bottom: 10px;
  border: 2px solid #999999;
  border-radius: 5px;
  background-color: #f0f0f0;
  color: #000000;
}

.fila {
  display: flex;
  justify-content: center;
  margin-bottom: 8px;
}

button {
  width: 50px;
  height: 45px;
  margin: 3px;
  font-size: 18px;
  border: 2px solid #666666;
  border-radius: 6px;
  cursor: pointer;
}

.numero {
  background-color: #ffffff;
  color: #333333;
}

.operador {
  background-color: #f7b733;
  color: #ffffff;
  font-weight: bold;
}

#btnIgual {
  background-color: #4caf50;
  color: #ffffff;
  font-weight: bold;
}

#btnLimpiar {
  background-color: #e74c3c;
  color: #ffffff;
  font-weight: bold;
}