body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 2rem;
  background-color: #f4f4f4;
  color: #111;
  transition: background-color 0.4s, color 0.4s;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
}

button {
  padding: 0.75rem 1.5rem;
  background-color: #00cc99;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.3s;
}

button:hover {
  background-color: #009977;
}

.hidden {
  display: none;
}

.login-container {
  max-width: 300px;
  margin: 5rem auto;
  background-color: #eee;
  padding: 2rem;
  border-radius: 8px;
}

.progress-container {
  background-color: #ccc;
  width: 100%;
  height: 20px;
  border-radius: 10px;
  overflow: hidden;
  margin-top: 1rem;
}

#progressBar {
  background-color: #00cc99;
  height: 100%;
  width: 0%;
  transition: width 1s;
}

body.dark {
  background-color: #111;
  color: #eee;
}