/* 容器基础布局 */
.gnuradio_main_container {
    display: flex;
    gap: 30px;
    margin: 16px 56px 0px 8px;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: #333;
}

/* 左侧主内容约束 */
.gnuradio_main_container .tutorial-main-container {
    flex: 3;
    min-width: 0; /* 防止 flex 子元素溢出 */
}

.gnuradio_main_container .tutorial-main-container .chapter_card {
    margin-bottom: 30px;
    background: #fff;
}

.gnuradio_main_container .tutorial-main-container .chapter_title {
    border-left: 4px solid #0073e6;
    padding-left: 10px;
    margin-block-start: 16px;
    margin-block-end: 8px;
}

.gnuradio_main_container .tutorial-main-container .lesson_list {
    list-style: none;
    padding: 0;
    margin: 0;
    overflow: hidden;
}

.gnuradio_main_container .tutorial-main-container .lesson_item {
    position: relative;
    cursor: pointer;
    padding-left: 1px;
    height: 32px;
    display: flex;
    align-items: center;
    border-bottom: 1px solid #eee;
}

.gnuradio_main_container .tutorial-main-container .lesson_item:last-child {
    /*border-bottom: none;*/
}

.gnuradio_main_container .tutorial-main-container .lesson_item:hover {
    background: #f8f9fa;
}

.gnuradio_main_container .tutorial-main-container .lesson_link {
    /*flex: 1;*/
    text-decoration: none;
    color: #0073e6;
    font-weight: bold;
}

.gnuradio_main_container .tutorial-main-container .icon_links {
    display: flex;
    gap: 15px;
    color: #888;
    align-items: center;
}

.gnuradio_main_container .tutorial-main-container .icon_links i {
    color: black;
}

.gnuradio_main_container .tutorial-main-container .icon_links i:hover {
    color: {{ topic.color or '#007bff' }};
}

 /* 仅约束主课与其子课程的折叠逻辑 */
.gnuradio_main_container .tutorial-main-container .lesson_item_container.collapsed .sub_lesson_list { display: none; }

.gnuradio_main_container .tutorial-main-container .lesson_link_wrapper { cursor: pointer; user-select: none; }

/* 子课程列表样式微调 */
.gnuradio_main_container .tutorial-main-container .sub_lesson_list { 
    list-style: none; 
    padding: 0 0 0 25px; 
    background: #fafafa; 
    border-top: 1px solid #eee; 
}
.gnuradio_main_container .tutorial-main-container .sub_lesson_item { 
    padding: 10px 18px; 
    border-bottom: 1px dashed #eee; 
    display: flex; 
    justify-content: space-between; 
    align-items: center; 
}
.gnuradio_main_container .tutorial-main-container .sub_lesson_item:last-child { border-bottom: none; }

/* 展开状态的指示图标旋转 */
.gnuradio_main_container .tutorial-main-container .fa-caret-down { transition: transform 0.2s; }
.gnuradio_main_container .tutorial-main-container .lesson_item_container:not(.collapsed) .fa-caret-down { transform: rotate(180deg); }


/* 右侧侧边栏约束 */
.gnuradio_main_container .tutorial-side-container {
    width: 300px;
    background: #f8f9fa;
    padding: 25px;
    border-radius: 12px;
    height: fit-content;
    position: sticky;
    top: 20px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
}

/* 移动端适配 */
@media (max-width: 768px) {
    .gnuradio_main_container {
        flex-direction: column;
    }
    .gnuradio_main_container .tutorial-side-container {
        width: 100%;
        order: -1; /* 小屏幕下侧边栏显示在上方 */
        position: static;
        box-sizing: border-box;
    }
    .gnuradio_main_container .tutorial-main-container {
        width: 100%;
    }
}