body {
  font-family: system-ui, sans-serif;
  margin: 0;
  padding: 0;
  line-height: 1.6;
  color: #222;
  background: #fafafa;
}
header {
  background: #111;
  color: #fff;
  padding: 2rem;
  text-align: center;
}
header h1 { margin: 0; font-size: 2.5rem; }
header nav a {
  color: #fff;
  margin: 0 10px;
  text-decoration: none;
}
section {
  max-width: 800px;
  margin: 2rem auto;
  padding: 1rem;
  background: #fff;
  border-radius: 10px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
h2 { border-bottom: 2px solid #ddd; padding-bottom: 5px; }
ul { padding-left: 20px; }
.btn {
  display: inline-block;
  padding: 10px 15px;
  background: #111;
  color: #fff;
  border-radius: 5px;
  text-decoration: none;
}
footer {
  text-align: center;
  padding: 1rem;
  margin-top: 2rem;
  background: #111;
  color: #fff;
}
.profile-img {
  width: 140px;
  height: 140px;
  border-radius: 50%;
  object-fit: cover;
  display: block;
  margin: 0 auto 1rem auto;
  border: 3px solid #ddd;
}