*,*::before,*::after{box-sizing:border-box;}
  :root{
    --bg:#f5f7fb; --card:#ffffff; --text:#1a2033; --muted:#5c6580; --line:#e4e8f2;
    --accent:#3b6cff; --accent-soft:#eef3ff;
    --warn:#c2410c; --warn-soft:#fff4e9; --warn-line:#ffd9bd;
    --ok:#0b8a4b; --ok-soft:#e7f7ee;
    --radius:14px; --nav-h:60px;
  }
  html{scroll-behavior:smooth;}
  body{
    margin:0; background:var(--bg); color:var(--text);
    font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
    font-size:15px; line-height:1.78; -webkit-font-smoothing:antialiased;
    padding-top:var(--nav-h);
  }
  /* 顶部导航 */
  .topnav{
    position:fixed; top:0; left:0; right:0; height:var(--nav-h);
    background:rgba(255,255,255,.92); backdrop-filter:saturate(180%) blur(12px);
    -webkit-backdrop-filter:saturate(180%) blur(12px);
    border-bottom:1px solid var(--line); z-index:50;
  }
  .topnav-inner{
    max-width:1180px; height:100%; margin:0 auto; padding:0 24px;
    display:flex; align-items:center; gap:28px;
  }
  .brand{display:flex; align-items:center; gap:9px; font-size:15.5px; font-weight:700; color:var(--text); text-decoration:none; flex:0 0 auto;}
  .brand-dot{width:22px;height:22px;border-radius:7px;background:linear-gradient(135deg,#3b6cff,#7a5cff);display:grid;place-items:center;color:#fff;font-size:12px;font-weight:700;}
  .nav-links{display:flex;align-items:center;gap:4px;list-style:none;margin:0;padding:0;overflow-x:auto;scrollbar-width:none;}
  .nav-links::-webkit-scrollbar{display:none;}
  .nav-links a{display:block;padding:7px 13px;border-radius:8px;font-size:14px;color:var(--muted);text-decoration:none;white-space:nowrap;transition:background .16s,color .16s;}
  .nav-links a:hover{color:var(--accent);background:var(--accent-soft);}
  .nav-cta{margin-left:auto;flex:0 0 auto;font-size:13.5px;font-weight:600;color:#fff;background:var(--accent);padding:8px 16px;border-radius:8px;text-decoration:none;transition:opacity .16s;cursor:pointer;}
  .nav-cta:hover{opacity:.88;}
  /* 主布局 */
  .wrap{max-width:1180px;margin:0 auto;padding:40px 24px 80px;display:grid;grid-template-columns:minmax(0,1fr) 236px;gap:40px;align-items:start;}
  /* 侧边目录 */
  .toc{position:sticky;top:calc(var(--nav-h) + 24px);font-size:13.5px;justify-self:end;width:100%;}
  .toc h2{font-size:11.5px;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin:0 0 12px;font-weight:700;}
  .toc ol{list-style:none;margin:0;padding:0;border-right:2px solid var(--line);}
  .toc li a{display:block;padding:6px 14px 6px 0;margin-right:-2px;color:var(--muted);text-decoration:none;border-right:2px solid transparent;transition:color .18s,border-color .18s;}
  .toc li a:hover{color:var(--accent);border-right-color:var(--accent);}
  /* 页头 */
  main{min-width:0;}
  .page-head{margin-bottom:32px;}
  .eyebrow{display:inline-block;font-size:12px;font-weight:600;letter-spacing:.06em;color:var(--accent);background:var(--accent-soft);padding:4px 12px;border-radius:999px;}
  h1{font-size:30px;line-height:1.32;margin:16px 0 10px;letter-spacing:-.01em;}
  .lead{color:var(--muted);margin:0;font-size:15px;}
  /* 区块 */
  section{scroll-margin-top:calc(var(--nav-h) + 20px);margin-bottom:48px;}
  .sec-title{display:flex;align-items:center;gap:10px;font-size:19px;margin:0 0 18px;letter-spacing:-.01em;}
  .sec-title::before{content:"";width:4px;height:18px;border-radius:2px;background:var(--accent);flex:0 0 auto;}
  /* Loomy 介绍 */
  .intro{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px 26px;margin-bottom:48px;box-shadow:0 1px 2px rgba(20,30,60,.04);}
  .intro h2{font-size:19px;margin:0 0 14px;letter-spacing:-.01em;display:flex;align-items:center;gap:10px;}
  .intro h2::before{content:"";width:4px;height:18px;border-radius:2px;background:var(--accent);flex:0 0 auto;}
  .intro p{margin:0 0 14px;}
  .intro p:last-of-type{margin-bottom:0;}
  .intro strong{color:#0f1a36;}
  .feature-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(210px,1fr));gap:12px;margin-top:20px;}
  .feature{background:#f8f9fd;border:1px solid var(--line);border-radius:10px;padding:14px 16px;}
  .feature h4{margin:0 0 6px;font-size:14px;display:flex;align-items:center;gap:7px;}
  .feature p{margin:0;font-size:13.5px;line-height:1.65;color:var(--muted);}
  /* 步骤卡片 */
  .step{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px 24px 24px;margin-bottom:18px;scroll-margin-top:calc(var(--nav-h) + 20px);box-shadow:0 1px 2px rgba(20,30,60,.04);}
  .step-head{display:flex;align-items:center;gap:12px;margin-bottom:14px;}
  .step-num{flex:0 0 30px;height:30px;border-radius:9px;background:var(--accent);color:#fff;display:grid;place-items:center;font-size:14px;font-weight:700;}
  .step-head h3{font-size:17px;margin:0;letter-spacing:-.01em;}
  .step p{margin:0 0 12px;}
  .step p:last-child{margin-bottom:0;}
  .step ul,.step ol{margin:0 0 14px;padding-left:22px;}
  .step li{margin-bottom:7px;}
  .step li:last-child{margin-bottom:0;}
  /* PPT 示例 */
  .example{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px 26px;margin:18px 0;scroll-margin-top:calc(var(--nav-h) + 20px);box-shadow:0 1px 2px rgba(20,30,60,.04);}
  .example-head{display:flex;align-items:center;gap:12px;margin-bottom:18px;}
  .example-tag{flex:0 0 auto;font-size:11.5px;font-weight:700;letter-spacing:.05em;color:var(--ok);background:var(--ok-soft);padding:3px 10px;border-radius:999px;}
  .example-head h3{font-size:17px;margin:0;letter-spacing:-.01em;}
  .example h4{font-size:14.5px;margin:20px 0 10px;letter-spacing:-.01em;}
  .example h4:first-of-type{margin-top:0;}
  .prompt-box{background:#f8f9fd;border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:8px;padding:14px 16px;font-size:14px;line-height:1.75;margin:10px 0 14px;}
  .prompt-box .label{display:block;font-size:11.5px;font-weight:700;letter-spacing:.06em;color:var(--muted);text-transform:uppercase;margin-bottom:6px;}
  .prompt-box p{margin:0;}
  .step-flow{list-style:none;margin:10px 0 14px;padding:0;counter-reset:flow;}
  .step-flow li{counter-increment:flow;position:relative;padding:8px 0 8px 34px;font-size:14px;border-bottom:1px dashed var(--line);}
  .step-flow li:last-child{border-bottom:none;}
  .step-flow li::before{content:counter(flow);position:absolute;left:0;top:9px;width:22px;height:22px;border-radius:6px;background:var(--accent-soft);color:var(--accent);font-size:12px;font-weight:700;display:grid;place-items:center;}
  /* FAQ */
  .faq-group{display:grid;gap:10px;}
  .faq-item{background:var(--card);border:1px solid var(--line);border-radius:12px;overflow:hidden;transition:border-color .18s,box-shadow .18s;}
  .faq-item[open]{border-color:#c9d6ff;box-shadow:0 2px 10px rgba(59,108,255,.07);}
  .faq-item summary{list-style:none;cursor:pointer;padding:15px 48px 15px 18px;font-size:14.5px;font-weight:600;line-height:1.6;position:relative;color:var(--text);transition:color .16s;}
  .faq-item summary::-webkit-details-marker{display:none;}
  .faq-item summary:hover{color:var(--accent);}
  .faq-item summary::after{content:"";position:absolute;right:20px;top:50%;width:8px;height:8px;border-right:2px solid var(--muted);border-bottom:2px solid var(--muted);transform:translateY(-70%) rotate(45deg);transition:transform .2s,border-color .2s;}
  .faq-item[open] summary::after{transform:translateY(-30%) rotate(-135deg);border-color:var(--accent);}
  .faq-body{padding:0 18px 16px;font-size:14px;line-height:1.75;color:var(--text);border-top:1px solid var(--line);padding-top:14px;}
  .faq-body p{margin:0 0 10px;}
  .faq-body p:last-child{margin-bottom:0;}
  .faq-body ul{margin:8px 0 10px;padding-left:20px;}
  .faq-body li{margin-bottom:6px;}
  .faq-body li:last-child{margin-bottom:0;}
  /* 表格 */
  .table-wrap{overflow-x:auto;margin:14px 0;}
  table{width:100%;min-width:520px;border-collapse:collapse;font-size:14px;border:1px solid var(--line);border-radius:10px;overflow:hidden;background:var(--card);}
  th,td{text-align:left;padding:10px 14px;border-bottom:1px solid var(--line);vertical-align:top;}
  th{background:#f8f9fd;font-weight:600;font-size:13px;color:var(--muted);white-space:nowrap;}
  tr:last-child td{border-bottom:none;}
  /* 代码 */
  code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.87em;background:#eef1f8;color:#2b3550;padding:2px 6px;border-radius:5px;word-break:break-word;}
  /* 提示框 */
  .note{display:flex;gap:10px;padding:12px 16px;border-radius:10px;font-size:14px;line-height:1.7;margin:14px 0;}
  .note:last-child{margin-bottom:0;}
  .note .ico{flex:0 0 auto;font-size:14px;line-height:1.7;}
  .note.warn{background:var(--warn-soft);border:1px solid var(--warn-line);color:#7a350c;}
  .note.info{background:var(--accent-soft);border:1px solid #d5e0ff;color:#22357a;}
  .note.ok{background:var(--ok-soft);border:1px solid #c6ead4;color:#0b5e36;}
  /* 页脚 */
  .footnote{margin-top:40px;padding-top:20px;border-top:1px solid var(--line);font-size:13px;color:var(--muted);}
  /* 响应式 */
  @media (max-width:900px){
    .wrap{grid-template-columns:1fr;gap:24px;padding:28px 18px 60px;}
    .toc{display:none;}
    h1{font-size:25px;}
    .step,.intro,.example{padding:20px 18px;}
    .feature-grid{grid-template-columns:1fr;}
    .nav-links{display:none;}
    .nav-cta{font-size:13px;padding:7px 13px;}
  }
  @media (max-width:640px){ .nav-cta{display:none;} }