body {
  font-family: '微软雅黑', sans-serif;
  background: #f5f6fa;
  color: #333;
  margin: 0;
  padding: 0;
}
 
header {
  background: #222;
  color: #fff;
  padding: 20px 0;
  text-align: center;
}
 
nav a {
  color: #fff;
  margin: 0 15px;
  text-decoration: none;
  transition: color 0.3s;
}
 
nav a:hover {
  color: #ff9800;
}
 
.intro {
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 40px 0;
}
 
.intro img {
  width: 120px;
  border-radius: 50%;
  margin-right: 30px;
}
