header {
  background-color: #333;
  color: white;
  text-align: center;
  padding: 1em;
}

h1 {
  font-size: 3em;
}

main {
  display: flex;
  justify-content: space-around;
  margin: 2em;
}

section {
  border: 1px solid #333;
  padding: 1em;
  width: 40%;
}

h2 {
  font-size: 2em;
  margin-bottom: 1em;
}

form label {
  display: inline-block;
  width: 100px;
}

form input {
  margin-bottom: 1em;
}

button {
  background-color: #333;
  color: white;
  padding: 0.5em 1em;
  border: none;
  border-radius: 4px;
}

.hidden {
  display: none;
}

#login-error {
  color: red;
}

#register-error {
  color: red;
}