.nav_list {
    position: fixed;
    top: 100px;

    display: none;
    background-color: #488a63;

    padding: 8px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);


    max-height: calc(100vh - 380px);
    overflow-y: hidden;
    overflow-x: hidden;

    z-index: 100;
}


.nav_list ul {
    list-style: none;
    margin: 0;
    padding: 0;
    background-color: white;
    padding: 8px;
    border-radius: 5px;

    max-height: calc(100vh - 350px);
    overflow-y: auto;
    overflow-x: hidden;
}


.nav_list a {
    text-decoration: none;
    color: #333;
    display: block;
    width: 100%;
    height: 100%;
}

.nav_list li ul li {
    margin-bottom: 5px;
}

.nav_list .first_level_link {
    font-size: 16px;
    font-weight: bold;
    transition: all 0.5s;
    margin: 5px 0;
}

.nav_list .second_level_link {
    padding-left: 15px;
    border-left: 2px solid #eee;
    font-size: 15px;
    transition: all 0.5s;
}


.nav_list .first_level_link.active {
    color: #2E8B57;
}

.nav_list .second_level_link.active {
    color: #2E8B57;
    font-weight: bold;
    border-left: 2px solid #2E8B57;

    /* color: white;
    background-color: #2E8B57;
    border-left: 2px solid #2E8B57;
    border-radius: 5px; */
}



.content h2 {
    font-size: 30px;
    color: #2E8B57;
}

.content h2:not(:first-of-type) {
    margin-top: 40px;
}

.content h3 {
    font-size: 24px;
    color: #4682B4;
    /* 蓝色 */
    margin-top: 10px;
}

.content .h2_p {
    font-size: 18px;
    line-height: 1.5;
}

.content .h3_p {
    font-size: 16px;
    line-height: 1.5;
    list-style-type: disc;
    margin-left: 20px;
}

.content .h3_p ul {
    font-size: 16px;
    line-height: 1.5;
    list-style-type: square;
    margin-left: 20px;
}

.content .h3_p strong {
    font-weight: bold;
}

.content .h3_p .italic {
    font-style: italic;
}

.content .qna_question {
    font-size: 18px;
    color: #4682B4;
}

.content .qna_answer {
    font-size: 16px;
    line-height: 1.5;
    margin-top: 10px;
    list-style-type: none;
}

.content .qna_answer .code_span {
    font-family: Consolas, monospace;
    font-size: 16px;
    background-color: #f0f0f0;
    padding: 2px 5px;
    border-radius: 5px;
    color: brown;
    box-shadow: 0 0 5px rgba(0, 0, 0, 0.1);
}

.content .title_container {
    display: flex;
    justify-content: flex-start;
    align-items: center;
}

.content .title_link {
    color: inherit;
    text-decoration: none;
}

.content .title_link_icon {
    /* 链接图标 */
    opacity: 0;
    transition: all 0.5s;
    width: 20px;
    margin: 5px 0 0 10px;
}

.content .image_container {
    position: relative;
    text-align: center;
    margin: 20px 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    /* height: 400px; */
    /* 可根据需求调整 */
}

.content .image_container .clickable_image {
    max-height: 380px;
    max-width: 980px;
    padding: 10px;
    cursor: pointer;
    transition: transform 0.3s ease;
    border-radius: 10px;
    box-shadow: 0px 4px 15px 8px rgba(0, 0, 0, 0.1);
}


.content .image_container .image_caption {
    margin-top: 15px;
    font-size: 15px;
    color: #555;
}


/* 放大图片时的遮罩层 */
.content .image_modal {
    display: none;
    /* 默认隐藏 */
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    /* 半透明黑色遮罩层 */
    z-index: 9999;
    justify-content: center;
    align-items: center;
    flex-direction: column;
}

/* 关闭按钮 */
.content .image_modal .close_button {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 30px;
    color: white;
    cursor: pointer;
}

.content .image_modal .image_modal_content {
    position: relative;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.content .image_modal .image_modal_content .zoomed_image {
    max-width: 90%;
    max-height: 80%;
    transition: transform 0.3s ease;
}

.content .image_modal .image_modal_content .zoomed_caption {
    margin-top: 10px;
    font-size: 16px;
    color: #ddd;
    text-align: center;
}



.title_link:hover {
    text-decoration: underline;
}

.title_link:hover+.title_link_icon {
    opacity: 1;
}

.expand_list_button {
    position: fixed;
    top: 100px;
    right: 20px;
    border: 5px solid #488a63;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    transition: all 0.5s;
    cursor: pointer;
    z-index: 99;
}


.expand_list_button img {
    width: 35px;
}

.expand_list_button:active {
    transform: scale(0.9);
}

.expand_list_button:hover {
    background-color: #f0f0f0;
}


.click_to_close2 {
    display: none;
    position: fixed;
    top: 120px;
    right: 40px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    transition: all 0.5s;
    cursor: pointer;
    z-index: 101;
}

.click_to_close2 .close_icon {
    width: 25px;
}

.click_to_close2:hover {
    transform: rotate(90deg);
}


/* 下列的响应式布局只是在页面初始化时生效，JavaScript控制着后续的屏幕动态变化的样式 */
/* 屏幕宽度不够大的时候，导航列表将隐藏，只有一个展开按钮 */
@media (max-width: 1440px) {
    .content {
        padding: 20px 40px 20px 20px;
    }

    .nav_list {
        display: none;
        right: 20px;
    }

    .expand_list_button {
        display: block;
    }
}

/* 屏幕宽度足够大的时候，导航列表将一直位于内容区右侧 */
@media (min-width: 1440px) {
    .content {
        padding: 20px 360px 20px 35px;
    }

    .nav_list {
        display: flex;
        right: calc((100vw - 1440px) / 2 + 20px);
    }

    .expand_list_button {
        display: none;
    }
}