@media (prefers-color-scheme: dark) {
  body {
    background-color: #333;
    color: #fff;
  }

  textarea {
    background-color: #444;
    color: #fff;
  }
}

body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
}

div {
  display: flex;
  justify-content: center;
}

textarea {
  width: 67vw;
  height: 67vh;
}

button,
input,
label {
  margin: 5px;
}