/* =========================================================
   We-Math · OpenBook (kb-openbook.css)
   统一风格：与 .nav-side 一致的淡蓝/薄荷系、柔和阴影
   兼容现有 HTML + JS（kb-openbook.js）
   ========================================================= */

/* -------- 根容器（书封） -------- */
.kb-openbook{
    max-width: 1200px;
    margin: 16px auto;
    position: relative;
    padding: 12px 14px 18px;
    background: #f8fbff;
    border-radius: 20px;
    border: 1.8px solid #e6eef7;
    box-shadow: 0 6px 32px 0 #d0d8e81e;
  }
  
  /* -------- 顶部：语言切换 + 章节 pill 条（可共用容器）-------- */
  .kb-openbook-topbar{
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 10px;
    margin-bottom: 8px;
  }
  
  /* 语言切换（你可在 HTML 中放两个按钮 id=kbLangEn / kbLangCn） */
  .kb-lang-switch{
    display: inline-flex;
    background: #fff;
    border: 1.7px solid #e7eef7;
    border-radius: 999px;
    padding: 4px;
    box-shadow: 0 1px 6px #e6edfa24;
    gap: 6px;
  }
  .kb-lang-switch button{
    border: none;
    background: #fff;
    color: #4b5b73;
    font-weight: 600;
    padding: 6px 12px;
    border-radius: 999px;
    cursor: pointer;
    transition: background .12s, color .12s, box-shadow .12s;
  }
  .kb-lang-switch button:hover{
    background: #f1f6fd;
    color: #1766c2;
    box-shadow: 0 2px 8px #aec7fd2a;
  }
  .kb-lang-switch button.active{
    background: #e8f6f3;
    color: #197676;
    box-shadow: 0 2px 8px #a2d5c61f;
    border: 1px solid #cfeae4;
  }
  
  /* 顶部超薄章节 pill 条 */
  .kb-openbook-toc{
    display:flex;
    gap:8px;
    justify-content:center;
    align-items:center;
    padding:8px;
    border-radius:12px;
    background:#fff;
    border:1.7px solid #e7eef7;
    box-shadow: inset 0 1px 6px #ecf2f9;
    margin: 10px 0 12px;
    overflow:auto;
  }
  .kb-openbook-toc .pill{
    padding:6px 12px;
    border-radius:999px;
    white-space:nowrap;
    cursor:pointer;
    user-select:none;
    font-weight:600;
    color:#4d5770;
    border:1px solid #eef4fb;
    background:#fafdff;
    transition:transform .12s, background .12s, color .12s, box-shadow .12s, border-left-width .18s;
  }
  .kb-openbook-toc .pill:hover{
    background: #f1f6fd;
    color: #1766c2;
    box-shadow: 0 3px 12px #aec7fd23;
  }
  .kb-openbook-toc .pill.active{
    color:#197676;
    background:#e8f6f3;
    border-color:#cfeae4;
    box-shadow: 0 2px 8px #a2d5c61f;
  }
  
  /* -------- 舞台（书内页） -------- */
  .kb-openbook-stage{
    position:relative;
    background: linear-gradient(#f5f8fd,#f8fbff);
    border-radius:16px;
    padding:18px;
    min-height: 540px;
  }
  
  /* 桌面光晕 */
  .kb-openbook-cover-shadow{
    position:absolute;
    inset:12px 18px auto 18px;
    height:20px;
    border-radius:12px;
    background: radial-gradient(40% 80% at 50% 0%, #b6cde617, transparent 70%);
    pointer-events:none;
  }
  
  /* 展开画面：左页 / 书脊 / 右页 */
  .kb-openbook-spread{
    position:relative;
    display:flex;
    align-items:stretch;
    justify-content:center;
    gap:0;
    max-width: 1100px;
    margin:0 auto;
    filter: drop-shadow(0 6px 16px rgba(176,196,222,.18));
  }
  
  /* 左右页（纸张感） */
  .kb-openbook-page{
    flex:1; min-width:0;
    background: radial-gradient(120% 120% at 50% 10%, #ffffff 0%, #fefefe 55%, #f6f8fb 100%);
    border:1.5px solid #e6edf6;
    padding:14px 16px;
    border-radius:12px;
    position:relative;
    box-shadow: inset 0 1px 10px #f0f5fb;
  }
  .kb-openbook-page.left  { border-top-right-radius:0; border-bottom-right-radius:0; }
  .kb-openbook-page.right { border-top-left-radius:0;  border-bottom-left-radius:0; }
  
  /* 书脊 */
  .kb-openbook-spine{
    width:22px;
    background: linear-gradient(90deg,#e9eef7 0%,#dfe6f1 50%,#e9eef7 100%);
    border-top:1px solid #dfe6f1;
    border-bottom:1px solid #dfe6f1;
    box-shadow: inset -6px 0 10px #d3deee66, inset 6px 0 10px #d3deee66;
  }
  
  /* 页眉：标题 + 搜索/提示 */
  .kb-openbook-page-head{
    display:flex; align-items:center; justify-content:space-between; gap:12px;
    margin-bottom:10px;
  }
  .kb-openbook-page-title{
    font-weight:800; color:#223c52; letter-spacing:.02em;
  }
  .kb-openbook-mini-hint{
    color:#7aa6be; font-size:.92em;
  }
  
  /* 搜索框 */
  .kb-openbook-search{
    border:1.6px solid #b5d5e9;
    border-radius:10px;
    padding:8px 12px;
    width:320px;
    outline:none;
    color:#295266;
    background:#fcfdff;
    box-shadow:0 2px 8px #e0e9f721;
    transition: border-color .12s, box-shadow .12s;
  }
  .kb-openbook-search:focus{
    border-color:#197676;
    box-shadow:0 2px 10px #a2d5c62a;
  }
  
  /* -------- 左页：树 -------- */
  .kb-openbook-tree{
    max-height: 430px;
    overflow:auto;
    padding-right:4px;
  }
  .kb-ob-tree{ list-style:none; margin:0; padding-left:0; }
  
  .kb-ob-node{
    position:relative;
    padding:7px 10px 7px 28px;
    margin:2px 0;
    border-radius:10px;
    transition: background .12s, box-shadow .12s, border-left-width .18s;
    background:#fff;
    border: 1px solid #f3f7fd;
    box-shadow: 0 1px 6px #e6edfa11;
  }
  .kb-ob-node:hover{
    background:#f1f6fd; 
    box-shadow:0 3px 12px #aec7fd23;
  }
  .kb-ob-toggle{
    position:absolute;
    left:6px; top:9px;
    width:16px; height:16px;
    border-radius:4px;
    display:flex; align-items:center; justify-content:center;
    font-size:12px; cursor:pointer; user-select:none;
    color:#356690;
    background:#eaf3fb;
    border:1px solid #d4e5f3;
    box-shadow: 0 1px 5px #dde7f31a;
  }
  .kb-ob-toggle.is-leaf{ visibility:hidden; }
  .kb-ob-label{
    color:#49566e;
    font-weight:600;
    letter-spacing:.02em;
    cursor:pointer;
  }
  .kb-ob-label.hit{
    background:linear-gradient(transparent 70%, #fff3b0 0);
    border-radius:5px;
    padding:0 2px;
  }
  .kb-ob-children{
    margin-left:12px;
    padding-left:12px;
    border-left:2px dotted #e6eef7;
    margin-top:6px;
  }
  
  /* 左页滚动条 */
  .kb-openbook-tree::-webkit-scrollbar{ width:8px; height:8px; }
  .kb-openbook-tree::-webkit-scrollbar-thumb{
    background:#dbe7f5; border-radius:8px;
  }
  .kb-openbook-tree::-webkit-scrollbar-thumb:hover{ background:#cbdcf3; }
  
  /* -------- 右页：知识点卡片网格 -------- */
  .kb-openbook-detail{
    max-height: 430px;
    overflow:auto;
    padding-right:4px;
  }
  
  /* 卡片网格（知识点为单位） */
  .kb-ob-grid{
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
  }
  @media (max-width: 1100px){
    .kb-ob-grid{ grid-template-columns: repeat(2, 1fr); }
  }
  @media (max-width: 720px){
    .kb-ob-grid{ grid-template-columns: 1fr; }
  }
  
  /* 单个知识点卡片 */
  .kb-ob-kp-block{
    background:#fff;
    border: 1.6px solid #e7eef7;
    border-radius: 14px;
    box-shadow: 0 6px 22px 0 #d0d8e81a, 0 1px 6px #e6edfa14;
    padding: 12px 12px 10px;
    transition: box-shadow .16s, border-color .14s, transform .12s;
  }
  .kb-ob-kp-block:hover{
    border-color:#cfe0f1;
    transform: translateY(-1px);
    box-shadow: 0 10px 28px 0 #cfd9ec28, 0 2px 8px #e6edfa20;
  }
  
  /* 卡片标题（知识点名称） */
  .kb-ob-kp-title{
    color:#223c52;
    font-weight: 800;
    margin-bottom: 8px;
    letter-spacing:.01em;
  }
  
  /* 卡片头（当显示“当前知识点名”时用） */
  .kb-ob-kp-head{
    color:#223c52;
    font-weight:800;
    font-size: 1.02em;
    margin: 2px 0 10px;
  }
  
  /* 考点胶囊 chips 区域 */
  .kb-ob-chips{
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
  }
  
  /* 单个考点 chip（点击展开） */
  .kb-ob-chip{
    display:inline-flex;
    align-items:center;
    gap: 8px;
    padding: 6px 12px;
    border-radius: 999px;
    font-size: 0.95em;
    color: #197676;
    background: #e8f6f3;
    border: 1px solid #cfeae4;
    box-shadow: 0 1px 6px #d4efea30;
    cursor: pointer;
    transition: background .12s, color .12s, box-shadow .12s, transform .1s;
  }
  .kb-ob-chip .dot{
    width: 7px; height: 7px; border-radius:50%;
    background: #7fc7b9; display:inline-block;
  }
  .kb-ob-chip:hover{
    background: #f1f6fd;
    color: #1766c2;
    box-shadow: 0 3px 12px #aec7fd25;
    transform: translateY(-1px);
  }
  .kb-ob-chip.active{
    background: #fff;
    color: #164e4b;
    border-color: #a2d5c6;
  }
  
  /* 考点描述（折叠区域） */
/* 描述贴在 chip 下：更紧凑但有分隔感 */
.kb-ob-desc{
    margin:6px 0 10px 22px;
    padding:8px 10px;
    border-radius:8px;
    border:1px dashed #cfe0ee;
    color:#335d7a;
    background:#f7fbff;
  }
  .kb-ob-chip.active{ box-shadow:0 1px 6px #dce9f5; }
  
  /* 当右页是“聚合列表”时，给块之间留点节奏 */
  .kb-openbook-detail .kb-ob-kp-block + .kb-ob-kp-block{
    margin-top: 8px;
  }
  
  /* 让“聚合视图”更像网格卡片：JS 里可以给 detail 包一层 .kb-ob-grid（聚合模式）
     — 如果你在 JS 中使用 kbRenderRightFromList，可在渲染前：
     detail.classList.add('kb-ob-grid');
     结束后再移除或保持。这里兼容块本身即网格项。 */
  .kb-openbook-detail.kb-ob-grid .kb-ob-kp-block{
    margin: 0;  /* 网格里由 gap 控制 */
  }
  
  /* 右页提示的弱化样式 */
  #kbObHint{
    color:#7aa6be;
  }
  
  /* -------- 翻页按钮 -------- */
  .kb-openbook-nav{
    position:absolute; top:50%; transform:translateY(-50%);
    border:none; width:40px; height:40px; border-radius:50%;
    background: linear-gradient(90deg,#a2d5c6,#e6eef8);
    color:#164e4b; font-weight:800;
    box-shadow: 0 1px 6px #d4efea44;
    cursor:pointer;
    transition: transform .12s, box-shadow .12s, filter .12s;
  }
  .kb-openbook-nav:hover{
    transform: translateY(-50%) scale(1.03);
    box-shadow: 0 3px 12px #aec7fd2b;
    filter: saturate(1.02);
  }
  .kb-openbook-nav.prev{ left:6px; }
  .kb-openbook-nav.next{ right:6px; }
  .kb-openbook-nav:disabled{ opacity:.35; cursor:not-allowed; }
  
  /* -------- 滚动条（右页） -------- */
  .kb-openbook-detail::-webkit-scrollbar{ width:8px; height:8px; }
  .kb-openbook-detail::-webkit-scrollbar-thumb{
    background:#dbe7f5; border-radius:8px;
  }
  .kb-openbook-detail::-webkit-scrollbar-thumb:hover{ background:#cbdcf3; }
  
  /* -------- 响应式 -------- */
  @media (max-width: 1100px){
    .kb-openbook{ padding:10px 10px 14px; }
    .kb-openbook-search{ width: 46vw; }
  }


  /* —— 聚合视图：纵向一列 —— */
.kb-openbook-detail.kb-ob-list {
    display: block;           /* 不用 grid 了 */
    padding-right: 4px;
  }
  .kb-openbook-detail.kb-ob-list .kb-ob-kp-block {
    margin: 12px 0;           /* 每个知识点卡片一行 */
  }
  
  /* —— 知识点卡片里的“考点”从胶囊改成整行条目 —— */
  .kb-openbook-detail .kb-ob-chips {
    display: flex;
    flex-direction: column;   /* 垂直排列每个考点 */
    gap: 8px;
  }
  
  .kb-openbook-detail .kb-ob-chip {
    width: 100%;
    justify-content: space-between;
    padding: 10px 12px;
    border-radius: 10px;
    font-size: 0.96em;
    background: #fff;
    color: #315a78;
    border: 1.6px solid #e7eef7;
    box-shadow: 0 1px 6px #e6edfa1f;
  }
  
  .kb-openbook-detail .kb-ob-chip:hover {
    background: #f7fbff;
    color: #1766c2;
    box-shadow: 0 3px 12px #aec7fd25;
  }
  
  .kb-openbook-detail .kb-ob-chip .dot {  /* 左侧小圆点保留一下节奏 */
    width: 7px; height: 7px; border-radius:50%;
    background: #7fc7b9; display:inline-block;
  }
  
  .kb-openbook-detail .kb-ob-chip::after { /* 右侧小箭头 */
    content: '⌄';
    font-size: 12px;
    opacity: 0.7;
    margin-left: 8px;
    transition: transform .12s ease;
  }
  .kb-openbook-detail .kb-ob-chip.active::after {
    transform: rotate(180deg);
  }
  
  /* 描述区域改成靠近条目，边距收紧一点 */
  .kb-openbook-detail .kb-ob-desc {
    margin: 6px 0 2px 0;
    padding: 10px 12px;
    border-radius: 10px;
    border: 1.4px dashed #cfe0ee;
    background: #f7fbff;
  }

  /* ============== 字体与语言态 ============== */
.kb-openbook {
    --font-ui-en: "Google Sans", "Inter", system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", Arial, sans-serif;
    --font-ui-cn: "Noto Sans", "PingFang SC", "Microsoft YaHei", system-ui, Arial, sans-serif;
    --font-display-en: "Castoro", "Playfair Display", Georgia, serif;
    --font-display-cn: "Noto Serif SC", "Songti SC", "Source Han Serif SC", "SimSun", serif;
  
    --font-ui: var(--font-ui-en);
    --font-display: var(--font-display-en);
  }
  
  .kb-openbook[data-lang="cn"] {
    --font-ui: var(--font-ui-cn);
    --font-display: var(--font-display-cn);
  }
  
  /* 页面内应用 */
  .kb-openbook, .kb-openbook * {
    font-family: var(--font-ui);
  }
  
  /* 右页主标题（更有展示感） */
  #kbObRightTitle {
    font-family: var(--font-display);
    font-weight: 800;
    letter-spacing: .02em;
    font-size: 1.15rem;
    color: #1f3750;
  }
  
  /* 左页标题稍弱一点，仍有层次 */
  #kbObLeftTitle {
    font-family: var(--font-display);
    font-weight: 700;
    color: #223c52;
  }
  
  /* ============== 顶部工具条 ============== */
  .kb-openbook-toolbar{
    display:flex;
    align-items:center;
    justify-content:space-between;
    gap:12px;
    padding:8px 10px;
    margin:8px 0 12px;
    background:#fff;
    border:1px solid #e8eef7;
    border-radius:12px;
    box-shadow: inset 0 1px 6px #ecf2f9;
  }
  
  /* 语言切换按钮组 */
  .kb-lang-switch{
    display:flex;
    gap:8px;
    align-items:center;
  }
  
  .kb-lang-btn{
    position:relative;
    appearance:none;
    border:none;
    padding:7px 14px;
    border-radius:999px;
    cursor:pointer;
    font-weight:700;
    font-size:.94rem;
    letter-spacing:.01em;
    color:#2b5167;
    background: linear-gradient(180deg,#fafdff 0%, #eef5fb 100%);
    border:1.5px solid #d7e6f5;
    box-shadow: 0 1px 6px #dfeaf81c;
    transition: transform .12s, box-shadow .12s, background .12s, color .12s, border-color .12s;
  }
  
  .kb-lang-btn:hover{
    transform: translateY(-1px);
    box-shadow: 0 3px 12px #cddff633;
    background: linear-gradient(180deg,#ffffff 0%, #eef5fb 100%);
  }
  
  .kb-lang-btn.active{
    color:#155e5a;
    background: linear-gradient(180deg,#e8f6f3 0%, #f1fbf8 100%);
    border-color:#bfe8df;
    box-shadow: 0 2px 10px #b9e7dc55, inset 0 1px 0 #ffffff;
  }
  
  /* 指引行（英文） */
  .kb-openbook-guide{
    flex:1;
    text-align:right;
    color:#6a87a0;
    font-size:.92rem;
    user-select:none;
    white-space:nowrap;
    overflow:hidden;
    text-overflow:ellipsis;
  }
  
  /* ============== 右页卡片/原理描述的细节打磨 ============== */
  .kb-ob-kp-block{
    border-radius:14px;
    background:#ffffff;
    border:1px solid #e7eef7;
    box-shadow: 0 1px 8px #e9f1fb5c;
  }
  
  .kb-ob-kp-title{
    font-family: var(--font-display);
    font-weight: 700;
    color:#244a66;
    margin-bottom:8px;
  }
  
  .kb-ob-chips .kb-ob-chip{
    border:1px solid #cfeae4;
    background:#f6fbff;
  }
  .kb-ob-chip.active{
    background:#e8f6f3;
    border-color:#bfe8df;
  }
  
  /* 描述块 */
  .kb-ob-desc{
    margin:6px 0 2px 0;
    padding:10px 12px;
    border-radius:10px;
    border:1px dashed #cfe0ee;
    color:#335d7a;
    background:#f7fbff;
    line-height:1.65;
  }