body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #f0f0f0;
  margin: 0;
}
 
.calculadora {
  background-color: yellow;
  padding: 20px;
  border-radius: 10px;
  box-shadow: 0px 4px 10px rgba(0, 0, 0, 0.3);
  width: 300px; /* tamanho médio */
  text-align: center;
}
 
input {
  width: 90%;
  margin: 5px;
  padding: 10px;
  font-size: 16px;
}
 
button {
  width: 60px;
  height: 40px;
  margin: 5px;
  font-size: 18px;
  cursor: pointer;
  border: none;
  border-radius: 5px;
}
 
button:hover {
  background-color: #ffd700;
}