body {
  font-family: 'Microsoft JhengHei', sans-serif;
  background: url('bg.png') no-repeat center center fixed;
  background-size: cover;
  margin: 0;
  padding: 0;
  color: #333;
}
nav a {
  margin: 0 5px;
  color: #2c3e50;
  text-decoration: none;
  font-weight: bold;
}
nav a:hover {
  color: #e67e22;
}
main {
  padding: 40px 20px;
}
header {
  position: relative;
}


header img { 
    padding-right: 400px;
    height: 80px;
    margin: 10px auto;
    margin-bottom: -30px;
    display: block;
}