body {
  background-color: black;
  color: white;
  font-family: monospace;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
}
.error-box {
  background-color: black;
  border: 1px solid white;
  padding: 20px;
  max-width: 600px;
}
.error-box h1 {
  font-size: 2em;
  margin: 0;
  color: red;
}
.hidden {
  display: none;
}