body {
    font-family: Arial, sans-serif;
    margin: 0;
    margin-top: 20px;
    margin-left: 0px;
    padding: 0;
    display: flex;
    flex-direction: column;
    height: 100vh;
    background-color: #18416f;
}

header {
    color: white;
    text-align: center;
    margin: 0px auto;
    top: 0px;
    align-items: center;
    justify-content: center;
    position: relative;
}

header img {
    max-width: 80%;
    height: auto;
    border-radius: 8px; /* 圆角 */
    padding: 0px; /* 内边距 */
}

main {
    display: flex;
    flex: 1;
    padding: 20px; /* 四周边距 */
}

.lnav {
    width: 200px;
    background: linear-gradient(to bottom, #082342, #18416f); /* 渐变背景 */
    padding: 1em;
    margin-right: 40px; /* 右边距 */
    margin-left: 80px;
    overflow-y: auto;
    border-radius: 36px; /* 圆角 */
    position: sticky;
    top: 20px; /* 距离顶部20px */
    max-height: calc(100vh - 80px); /* 减去上下边距，增加底部间距 */
    display: flex;
    flex-direction: column;
}

.lnav ul {
    list-style-type: none;
    padding: 0;
    margin-bottom: 60px; /* 底部留出一定间距 */
}

.lnav ul li {
    margin: 0.5em 0;
}

.lnav ul li a {
    text-decoration: none;
    color: #87abcf;
    display: block;
    padding: 0.5em;
    border-radius: 4px;
}

.lnav ul li a.active {
    font-weight: bold;
    font-size: larger;
    color: white;
}

section {
    flex: 1;
    padding: 3em;
    margin-right: 120px;
    background-color: #faf9e6;
    border-radius: 36px; /* 圆角 */
    position: relative; /* 为了定位右下角的框框 */
    margin-bottom: 50px;
}

section::after {
    content: '';
    position: absolute;
    bottom: -30px; /* 向下偏移 */
    right: -15px; /* 向右偏移 */
    width: calc(100% + 10px); /* 宽度增加10px */
    height: calc(100% + 10px); /* 高度增加10px */
    background-color: #799cbe; /* 黑色背景 */
    border-radius: 36px; /* 圆角 */
    z-index: -1; /* 置于底层 */
    
}

h2 {
    padding-top: 20px; /* 给标题留出空间 */
}

.collapsible {
    background-color: #06377c;
    color: white;
    cursor: pointer;
    padding: 10px;
    width: 100%;
    border: none;
    text-align: left;
    outline: none;
    font-size: 15px;
    border-radius: 8px;
    margin-top: 10px;
}

.content {
    padding: 0 18px;
    display: none;
    overflow: hidden;
    background-color: #b4d4dc;
    border-radius: 8px;
    margin-top: 10px;
    border: 2px solid #06377c; /* 美化边框 */
    padding: 10px; /* 内边距 */
}

.justified-paragraph {
    text-align: justify;
    text-align-last: left;
}

.image-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px; /* 图片之间的间距 */
}

.centered-image {
    max-width: 100%;
    height: auto;
    border-radius: 8px; /* 圆角 */
    padding: 0px; /* 内边距 */
}

.two-images{
    max-width: calc(50% - 20px); /* 两张图片占一半，减去间距 */
    height: auto;
    border-radius: 8px; /* 圆角 */
    padding: 0px; /* 内边距 */
}


.image-wrapper {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px; /* 图片和注释之间的间距 */
    margin-top: 20px;
    margin-bottom: 30px;
}
.image-caption {
    font-size: 12px; /* 减小字体大小 */
    font-family: Poppins_Light, sans-serif;
    color: #888; /* 浅灰色文字 */
    text-align: center;
    margin: 0;
    padding: 0;
}

section p {
    font-style: normal;
    font-weight: 400;
    font-family: Poppins, sans-serif;
}

section h2 {
    font-style: normal;
    font-weight: 900;
    font-family: Poppins_Bold, sans-serif;
    margin-top: 10px; /* 调整上边距 */
    margin-bottom: 10px; /* 调整下边距 */
}

section h1 {
    font-style: normal;
    font-weight: 900;
    font-family: Poppins_Bold, sans-serif;
    font-size: 40px;
    text-align: center;
    color: #305eab;
    margin-top: 40px; /* 保持较大的上边距 */
    margin-bottom: 40px; /* 保持较大的下边距 */
}

@font-face {
    font-family: 'Poppins';
    src: url('./Poppins-Regular.ttf') format('truetype');
    font-style: normal;
}

@font-face {
    font-family: 'Poppins_Light';
    src: url('./Poppins-Light.ttf') format('truetype');
    font-style: normal;
}

@font-face {
    font-family: 'Poppins_Bold';
    src: url('./Poppins-Bold.ttf') format('truetype');
    font-weight: 900;
    font-style: normal;
}

.cn_font-face {
    font-style: normal;
    font-weight: 100 400;
    font-size: 20px;
}

.reference-section {
    margin-bottom: 20px; /* 每个参考文献部分之间的间距 */
    padding: 15px; /* 内边距 */
    background-color: #f9f9f9; /* 背景颜色 */
    border-left: 4px solid #305eab; /* 左侧边框颜色 */
    border-radius: 4px; /* 圆角 */
}

.reference-section h2 {
    margin-top: 0; /* 去掉顶部边距 */
    font-size: 18px; /* 调整字体大小 */
    margin-bottom: 10px; /* 标题与内容之间的间距 */
}

.reference-list {
    list-style-type: none; /* 去掉默认的列表样式 */
    padding: 0;
    margin: 0;
}

.reference-list li {
    margin-bottom: 10px; /* 每个参考文献之间的间距 */
}

.reference-list p {
    margin: 0;
    font-size: 14px; /* 字体大小 */
    line-height: 1.6; /* 行高 */
    color: #333; /* 字体颜色 */
}

.button-container {
    display: flex;
    justify-content: space-around;
    margin: 20px 0;
}

.toggle-button {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
}

.content-container {
    border: 1px solid #ccc;
    padding: 20px;
    border-radius: 4px;
    background-color: #f9f9f9;
}

.content {
    display: none;
}
.content.active {
    display: block;
}
.vertical-sections{
    width: calc(100% - 360px);
    gap: 20px;
    display: flex;
    flex-direction: column;
}
hr.section-divider {
    border: none;
    border-top: 2px solid #ccc;
    margin: 20px 0; /* 上下间距 */
}
.button-container {
    display: flex;
    justify-content: space-around;
    margin: 20px 0;
}

.toggle-button {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s, color 0.3s, transform 0.2s, box-shadow 0.2s;
    border: none;
    border-radius: 4px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.toggle-button:hover {
    background-color: #007BFF;
    color: white;
    transform: scale(1.05);
    box-shadow: 0 6px 8px rgba(0, 0, 0, 0.15);
}

.toggle-button:active {
    transform: scale(0.95);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}
.vertical-sections section:not(:last-child) {
    border-bottom: 2px solid #ccc; /* 分隔线 */
}
.option {
    display: none;
    overflow: hidden;
    background-color: #b4d4dc;
    border-radius: 8px;
    border: 2px solid #06377c; /* 美化边框 */
    padding: 10px 10px; /* 内边距 */
    opacity: 0;
    width: 100%;
    position: absolute;
    transform: scale(0.95);
    transition: opacity 0.5s ease, transform 0.5s ease; /* 添加消失浮现效果 */
}

.option.active {
    display: block;
    opacity: 1;
    transform: scale(1);
    position: relative;
}

.option.inactive {
    display: block;
    opacity: 0;
    transform: scale(0.95);
}
.option-container {
    position: relative;
    margin-top: 10px;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

.image-container2 {
    overflow: hidden; /* 确保浮动元素不会超出容器 */
    margin: 20px 0;
}

.image-wrapper2 {
    max-width: calc(50% - 20px); /* 两张图片占一半，减去间距 */
    height: auto;
    float: left;
    margin-right: 20px;
}

.image-wrapper2 img {
    max-width: 100%;
    height: auto;
    display: block;
}

.image-caption2 {
    text-align: center;
    margin-top: 10px;
}