:root{
    --bg:#f5f7fb; --panel:#ffffff; --ink:#1f2937; --muted:#6b7280;
    --line:#e5e7eb; --shadow:0 6px 24px rgba(31,41,55,.08);
    --c-root:#0f172a; --c-hub:#475569; --c-core:#dc2626; --c-layer:#ea580c; --c-wing:#d97706;
    --c-lit:#7c3aed; --c-mod:#2563eb; --c-point:#0d9488;
  }
  *{box-sizing:border-box;}
  html,body{margin:0;height:100%;font-family:"PingFang SC","Microsoft YaHei",system-ui,-apple-system,Segoe UI,Roboto,sans-serif;color:var(--ink);background:var(--bg);}
  #app{display:flex;height:100vh;overflow:hidden;}
  #side{width:330px;flex:0 0 330px;background:var(--panel);border-right:1px solid var(--line);display:flex;flex-direction:column;box-shadow:var(--shadow);z-index:5;}
  #side header{padding:16px 18px 10px;border-bottom:1px solid var(--line);}
  #side h1{font-size:16px;margin:0 0 4px;letter-spacing:.3px;}
  #side .sub{font-size:11.5px;color:var(--muted);line-height:1.5;}
  .search{margin:12px 16px 4px;}
  .search input{width:100%;padding:8px 11px;border:1px solid var(--line);border-radius:10px;font-size:13px;outline:none;transition:.15s;}
  .search input:focus{border-color:var(--c-mod);box-shadow:0 0 0 3px rgba(37,99,235,.12);}
  .tree{padding:6px 10px 10px;overflow:auto;flex:1;font-size:13px;}
  .tree .row{display:flex;align-items:center;gap:6px;padding:5px 6px;border-radius:8px;cursor:pointer;user-select:none;line-height:1.3;}
  .tree .row:hover{background:#f1f5f9;}
  .tree .chev{width:14px;flex:0 0 14px;text-align:center;color:var(--muted);font-size:10px;transition:transform .15s;}
  .tree .chev.open{transform:rotate(90deg);}
  .tree .chev.leaf{visibility:hidden;}
  .tree .swatch{width:10px;height:10px;border-radius:3px;flex:0 0 10px;}
  .tree .lbl{flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
  .tree .cnt{font-size:10.5px;color:var(--muted);background:#f1f5f9;padding:1px 6px;border-radius:20px;}
  .tree .children{margin-left:14px;border-left:1px dashed var(--line);padding-left:4px;}
  .tip{padding:10px 16px;border-top:1px solid var(--line);font-size:10.5px;color:var(--muted);line-height:1.6;}
  #main{flex:1;position:relative;overflow:hidden;background:
    radial-gradient(circle at 18% 18%,#eef2ff 0,transparent 40%),
    radial-gradient(circle at 82% 82%,#ecfeff 0,transparent 42%),
    var(--bg);}
  svg{width:100%;height:100%;display:block;cursor:grab;}
  svg:active{cursor:grabbing;}
  .link{stroke:#cbd5e1;stroke-opacity:.5;}
  .node circle{cursor:pointer;stroke:#fff;stroke-width:2px;transition:opacity .15s;}
  .node text{pointer-events:none;font-size:11px;fill:var(--ink);paint-order:stroke;stroke:#fff;stroke-width:3px;stroke-linejoin:round;}
  .node.dim{opacity:.1;}
  .link.dim{stroke-opacity:.05;}
  .node.hi circle{stroke:#0f172a;stroke-width:3px;}
  #detail{position:absolute;top:16px;right:16px;width:320px;max-height:calc(100% - 32px);overflow:auto;background:var(--panel);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);padding:18px;display:none;z-index:6;}
  #detail h2{margin:0 0 4px;font-size:16px;}
  #detail .tag{display:inline-block;font-size:11px;color:#fff;padding:2px 9px;border-radius:20px;margin:2px 4px 8px 0;}
  #detail p{font-size:12.5px;line-height:1.6;color:#374151;margin:7px 0;}
  #detail .meta{border-top:1px dashed var(--line);padding-top:9px;margin-top:9px;}
  #detail .rel span{display:inline-block;background:#f1f5f9;border-radius:6px;padding:2px 8px;font-size:11px;margin:3px 4px 0 0;color:#334155;}
  #detail .close{position:absolute;top:10px;right:14px;cursor:pointer;color:var(--muted);font-size:18px;line-height:1;}
  #detail .exam{background:#f8fafc;border:1px solid #e2e8f0;border-left:3px solid var(--c-mod);border-radius:8px;padding:9px 11px;margin:8px 0;font-size:12px;line-height:1.6;}
  #detail .exam b{color:#0f172a;}
  #detail .qnum{color:#b45309;font-weight:600;}
  .ctrl{position:absolute;left:16px;bottom:16px;display:flex;gap:8px;z-index:6;}
  .ctrl button{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:8px 12px;font-size:13px;cursor:pointer;box-shadow:var(--shadow);color:var(--ink);}
  .ctrl button:hover{border-color:var(--c-mod);}
  .hint{position:absolute;left:16px;top:14px;font-size:12px;color:var(--muted);background:rgba(255,255,255,.8);padding:6px 12px;border-radius:20px;backdrop-filter:blur(4px);}
  @media (max-width:860px){#side{width:0;flex-basis:0;display:none;}#detail{width:calc(100% - 32px);}}
  /* ===== 考频相关 ===== */
  .ctrl button.active{background:var(--c-mod);color:#fff;border-color:var(--c-mod);}
  #detail .freqbox{display:flex;align-items:center;gap:8px;margin:6px 0 2px;}
  #detail .freqbox .lab{font-size:12px;color:#475569;white-space:nowrap;}
  #detail .freqbox .fbar{flex:1;height:9px;background:#eef2f7;border-radius:5px;overflow:hidden;min-width:60px;}
  #detail .freqbox .fbar i{display:block;height:100%;background:linear-gradient(90deg,#f59e0b,#ef4444);}
  #detail .freqbox .fval{font-size:15px;font-weight:700;color:#b45309;}
  #rank{position:absolute;right:16px;bottom:16px;width:236px;max-height:48vh;overflow:auto;background:rgba(255,255,255,.97);border:1px solid var(--line);border-radius:14px;box-shadow:var(--shadow);padding:12px 12px 10px;display:none;z-index:6;}
  #rank h3{margin:0 0 8px;font-size:13px;display:flex;justify-content:space-between;align-items:center;}
  #rank .x{cursor:pointer;color:var(--muted);font-size:16px;line-height:1;}
  .rk{display:flex;align-items:center;gap:6px;padding:3px 2px;cursor:pointer;border-radius:6px;}
  .rk:hover{background:#f1f5f9;}
  .rk .no{width:18px;font-size:11px;color:var(--muted);text-align:right;flex:0 0 18px;}
  .rk .nm{flex:1;font-size:11.5px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;}
  .rk .bar{width:50px;height:7px;background:#eef2f7;border-radius:4px;overflow:hidden;flex:0 0 50px;}
  .rk .bar i{display:block;height:100%;background:linear-gradient(90deg,#0d9488,#2563eb);}
  .rk .vv{width:20px;text-align:right;font-size:11px;color:#0f172a;flex:0 0 20px;font-weight:600;}
  .legend{position:absolute;right:16px;top:14px;background:rgba(255,255,255,.86);border:1px solid var(--line);border-radius:12px;padding:10px 12px;font-size:11px;color:#475569;box-shadow:var(--shadow);backdrop-filter:blur(4px);max-width:210px;line-height:1.7;z-index:6;}
  .legend b{color:#0f172a;}
  .legend .dot{display:inline-block;width:10px;height:10px;border-radius:50%;vertical-align:middle;margin-right:4px;}
  /* ===== 视角切换 ===== */
  .viewbar{position:absolute;left:50%;top:12px;transform:translateX(-50%);display:flex;gap:0;background:#fff;border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);overflow:hidden;z-index:7;}
  .viewbar button{background:#fff;border:none;padding:8px 16px;font-size:13px;cursor:pointer;color:var(--muted);font-weight:600;}
  .viewbar button+button{border-left:1px solid var(--line);}
  .viewbar button.active{background:var(--c-mod);color:#fff;}
  #svg2{width:100%;height:100%;display:none;cursor:grab;}
  #svg2:active{cursor:grabbing;}
  /* 学习视角控制/图例隐藏切换 */
  #ctrlLearn{display:none;}
  #legend2{display:none;}
  /* 学习视角节点 */
  #svg2 .tk circle{cursor:pointer;stroke:#fff;stroke-width:2px;transition:opacity .15s;}
  #svg2 .tk text{pointer-events:none;font-size:10.5px;fill:var(--ink);paint-order:stroke;stroke:#fff;stroke-width:3px;stroke-linejoin:round;}
  #svg2 .tk.dim{opacity:.08;}
  #svg2 .link{stroke:#cbd5e1;stroke-opacity:.5;}
  #svg2 .link.dim{stroke-opacity:.04;}
  #svg2 .tk.anchor circle{stroke:#0f172a;stroke-width:3px;}
  #svg2 .tk.hi circle{stroke:#ef4444;stroke-width:3.5px;}
  /* 学习路径弹窗 */
  #learnModal{position:absolute;inset:0;background:rgba(15,23,42,.45);display:none;z-index:20;align-items:center;justify-content:center;}
  #learnModal .box{width:min(560px,92vw);max-height:82vh;overflow:auto;background:#fff;border-radius:16px;box-shadow:0 20px 60px rgba(0,0,0,.3);padding:22px 24px;}
  #learnModal h3{margin:0 0 4px;font-size:16px;}
  #learnModal .sub{font-size:12px;color:var(--muted);margin-bottom:12px;line-height:1.5;}
  #learnModal .x{float:right;cursor:pointer;color:var(--muted);font-size:20px;line-height:1;}
  .lp-band{font-size:12px;font-weight:700;color:#0f172a;margin:14px 0 6px;padding-left:8px;border-left:3px solid var(--c-mod);}
  .lp-step{display:flex;gap:10px;align-items:flex-start;padding:7px 10px;border-radius:10px;background:#f8fafc;margin-bottom:6px;cursor:pointer;border:1px solid #eef2f7;}
  .lp-step:hover{background:#eef2ff;border-color:#c7d2fe;}
  .lp-step .no{width:22px;height:22px;flex:0 0 22px;border-radius:50%;background:var(--c-mod);color:#fff;font-size:12px;display:flex;align-items:center;justify-content:center;font-weight:700;}
  .lp-step .t{font-size:13px;color:#1f2937;font-weight:600;}
  .lp-step .c{font-size:11px;color:var(--muted);margin-top:1px;}
  .lp-step.final{background:#fff7ed;border-color:#fed7aa;}
  .lp-step.final .no{background:#ea580c;}
  #detail .tksec{border-top:1px dashed var(--line);padding-top:9px;margin-top:9px;}
  #detail .tksec h4{margin:0 0 6px;font-size:12.5px;color:#0f766e;}
  #detail .tksec .tkn{font-size:12px;line-height:1.55;color:#374151;margin:5px 0;}
  #detail .tksec .std{font-size:11.5px;color:#475569;background:#f1f5f9;border-left:3px solid #14b8a6;border-radius:6px;padding:5px 9px;margin:4px 0;}
  #detail .tksec .pre{display:inline-block;background:#eef2ff;border:1px solid #c7d2fe;border-radius:6px;padding:2px 8px;font-size:11px;margin:3px 4px 0 0;color:#3730a3;cursor:pointer;}
  #detail .tksec .pre:hover{background:#dbeafe;}
  #detail .lkbtn{display:block;width:100%;margin-top:10px;background:var(--c-mod);color:#fff;border:none;border-radius:9px;padding:9px;font-size:13px;cursor:pointer;font-weight:600;}
  #detail .lkbtn:hover{background:#1d4ed8;}
  .anchortag{display:inline-block;font-size:10.5px;color:#fff;background:#ef4444;border-radius:20px;padding:1px 8px;margin:2px 4px 6px 0;}