/* 简单的全局样式 */
body {
    font-family: Arial, Helvetica, sans-serif;
    margin: 0; padding: 0;
    background-color: #f9f9f9;
    color: #333;
    line-height: 1.6;
}
header {
    background-color: #4a90e2;
    color: #fff;
    padding: 1rem;
    text-align: center;
}
nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    gap: 1rem;
    padding: 0;
    margin: 0;
}
nav a {
    color: #fff;
    text-decoration: none;
}
main { padding: 2rem; }
footer { text-align: center; padding: 1rem; background: #eee; }
<!-- ping -->