body {
  padding: 0;
  margin: 0;
  background: linear-gradient(to right, #00aaff, #00ff6c);
}
.calculadora-grilla {
  display: grid;
  justify-content: center;
  align-content: center;
  min-height: 100vh;
  grid-template-columns: repeat(4, 100px);
  grid-template-rows: minmax(120px, auto) repeat(5, 100px);
}
.calculadora-grilla > button {
  cursor: pointer;
  font-size: 2rem;
  border: 1px solid #fff;
  outline: none;
  background-color: rgba(255, 255, 255, 0.75);
}
.output {
  grid-column: 1 / -1;
  background-color: rgba(0, 0, 0, 0.75);
  display: flex;
  justify-content: space-around;
  align-items: flex-center;
  flex-direction: column;
  padding: 10px;
  word-wrap: break-word;
  word-break: break-all;
}
.output .display {
  color: black;
  font-size: 1.85rem;
  text-align: right;
  width: auto;
}
.calculadora-grilla > button:hover {
  background-color: rgba(255, 255, 255, 0.9);
}