.container {
  display: flex;
  flex-direction: row;
  margin-bottom: 20px;
}

body {
  height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

input {
  font-size: 2em;
  max-width: 100px;
}

.result {
  border: 1px solid black;
  padding-left: 20px;
  padding-right: 20px;
}

button {
  font-size: 2.2em;
}

.error {
  color: red;
  margin-bottom: 20px;
  font-size: 1em;
}

.number {
  font-size: 2em;
}