* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: #f5f5f5;
  color: #333;
}

nav {
  background: #fff;
  border-bottom: 1px solid #ddd;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

.nav-brand {
  font-weight: bold;
  font-size: 1.2rem;
}

.nav-links a {
  margin-left: 1.5rem;
  color: #007bff;
  text-decoration: none;
}

.nav-links a:hover {
  text-decoration: underline;
}

main {
  max-width: 600px;
  margin: 2rem auto;
  padding: 2rem;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

h1 {
  margin-bottom: 1.5rem;
  color: #222;
}

h2 {
  margin: 1rem 0;
  font-size: 1.2rem;
  color: #222;
}

p {
  margin: 1rem 0;
  line-height: 1.6;
}

a {
  color: #007bff;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.form-container {
  max-width: 400px;
}

.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

input[type='text'],
input[type='email'],
input[type='password'] {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid #ddd;
  border-radius: 4px;
  font-size: 1rem;
}

input[type='text']:focus,
input[type='email']:focus,
input[type='password']:focus {
  outline: none;
  border-color: #007bff;
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}

button {
  background: #007bff;
  color: white;
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 4px;
  font-size: 1rem;
  cursor: pointer;
  width: 100%;
  font-weight: 500;
}

button:hover {
  background: #0056b3;
}

.error-message {
  background: #f8d7da;
  color: #721c24;
  padding: 1rem;
  border-radius: 4px;
  margin-bottom: 1.5rem;
  border: 1px solid #f5c6cb;
}

.user-card {
  background: #f8f9fa;
  padding: 1.5rem;
  border-radius: 4px;
  margin: 1.5rem 0;
}

dl {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 1rem;
}

dt {
  font-weight: 600;
  color: #555;
}

dd {
  color: #333;
}