body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 20px;
    color: #333;
}

h1, h2, h3, h4 {
    color: #0056b3;
    text-align: left; /* 确保标题左对齐 */
}

header h1 {
    text-align: center; /* 首页标题居中 */
}

header {
    text-align: center;
    background-color: #87CEEB; /* 天蓝色背景 */
    padding: 20px 0;
}

nav ul {
    list-style: none;
    padding: 0;
    text-align: center;
    display: flex;
    justify-content: center;
    gap: 15px; /* 调整导航链接之间的间距 */
}

nav ul li {
    display: inline;
}

nav ul li a {
    text-decoration: none;
    color: #333;
    padding: 10px;
}

nav ul li a:hover {
    background-color: #f0f0f0; /* 添加悬停效果 */
}

.profile-picture {
    text-align: center;
    margin: 20px 0;
}

.profile-picture img {
    width: 200px;
    height: auto;
}

footer {
    text-align: center;
    margin-top: 20px;
}

main {
    text-align: left;
    margin: 0 auto;
    max-width: 800px; /* 限制内容宽度 */
}

ul {
    padding-left: 20px; /* 调整列表项的缩进 */
}

main p {
    text-align: left; /* 确保段落左对齐 */
}