html {
  box-sizing: border-box;
}

*,
*::before,
*::after {
  box-sizing: inherit;
}

body {
  padding: 0;
  margin: 0;
}

.calculator {
  width: 400px;
  background-color: black;
  color: white;
  font-family: "Courier New", Courier, monospace;
}

.screen {
  padding: 20px 5px;
  text-align: right;
  font-size: 40px;
}

.buttons {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(5, 1fr);
  gap: 2px;
}

.grid-col-1-3 {
  grid-column: 1/3;
}

.grid-col-1-4 {
  grid-column: 1/4;
}

.button {
  height: 100px;
  font-size: 40px;
  background-color: #d8d9db;
  border: none;
  border-radius: 0;
}

.button:hover {
  background-color: #ebebeb;
}

.operator {
  background-color: #df974c;
  color: white;
}

.operator:hover {
  background-color: #dfb07e;
}