/* 导航栏样式 */
nav {
    background-color: #333;
    color: white;
    height: 50px;
}

nav ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

nav li {
    float: left;
}

nav a {
    display: block;
    color: white;
    text-align: center;
    padding: 16px;
    text-decoration: none;
}

nav a:hover {
    background-color: #ddd;
    color: black;
}

/* 页眉样式 */
header {
    background-color: #eee;
    padding: 20px;
}

header h1 {
    margin-top: 0;
}

/* 主体内容样式 */
main {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

section {
    margin-bottom: 20px;
}

section h2 {
    font-size: 24px;
    margin-top: 0;
}

/* 页脚样式 */
footer {
    background-color: #333;
    color: white;
    padding: 20px;
    text-align: center;
}

footer a {
    color: white;
}

footer a:hover {
    color: #ddd;
}