@charset "utf-8";

.calculator {
  width: 300px;
  margin: 0 auto;
  padding: 10px;
  background: #f5f5f5;
  border: 1px solid #ccc;
}

.calculator input[type="text"] {
  width: 100%;
  margin-bottom: 10px;
  padding: 5px;
  font-size: 18px;
}

.calculator .buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-gap: 5px;
}

.calculator button {
  width: 100%;
  padding: 10px;
  font-size: 18px;
}