/* 全局样式 */
body {
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    color: #333;
    background-color: #f5f5f5;
}

/* 头部样式 */
header {
    background-color: #1a1a1a;
    color: white;
    padding: 20px;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 2.5rem;
}

/* 导航栏样式 */
nav ul {
    list-style: none;
    padding: 0;
    margin: 20px 0 0;
    display: flex;
    justify-content: center;
    gap: 20px;
}

nav a {
    color: white;
    text-decoration: none;
    font-weight: bold;
    transition: color 0.3s;
}

nav a:hover {
    color: #ffcc00;
}

nav a.active {
    color: #ffcc00;
    text-decoration: underline;
}

/* 主要内容样式 */
main {
    max-width: 1200px;
    margin: 20px auto;
    padding: 20px;
    background-color: white;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

section {
    margin-bottom: 40px;
}

h2 {
    color: #1a1a1a;
    border-bottom: 2px solid #ffcc00;
    padding-bottom: 10px;
    margin-bottom: 20px;
}

/* 列表样式 */
ul {
    padding-left: 20px;
}

ul li {
    margin-bottom: 10px;
}

/* 链接样式 */
a {
    color: #0077cc;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

/* 页脚样式 */
footer {
    background-color: #1a1a1a;
    color: white;
    text-align: center;
    padding: 15px;
    margin-top: 40px;
}

/* 视频居中样式 */
#about {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

/* 响应式设计 */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    nav ul {
        flex-direction: column;
        gap: 10px;
    }

    main {
        padding: 15px;
    }
}