body{
    margin: 0;
    font-family:Arial,"微软雅黑",sans-serif;
    border-color: #f5f5f5;
}

.header{
    background-color: #333;
    color: #fff;
    padding: 20px;
}

.header h1{
    margin: 0;
}

.nav {
    margin-top: 10px;
}
.nav a{
    color: #fff;
    margin-right: 15px;
    text-decoration: none;
}

.nav a:hover {
    text-decoration: underline;
}
.main{
    padding: 20px;
}
.footer{
    text-align: center;
    padding: 10px;
    border-color: #222;
    color: #ccc;
}