:root{
    --bg:#f3ece0;
    --paper:#fffcf5;
    --ink:#2b2119;
    --muted:#8c7a68;
    --accent:#9a3b26;
    --accent-soft:#f3e6dc;
    --border:#e6d9c8;
    --topbar-bg:rgba(255,252,245,.92);
    --fs:19px;
    --lh:1.95;
    --reader-font:"Songti SC","STSong","SimSun","NSimSun",serif;
    --shadow:0 8px 30px rgba(60,40,20,.08);
  }
  [data-theme="dark"]{
    --bg:#14100d;
    --paper:#1e1814;
    --ink:#e9ddd0;
    --muted:#a08a76;
    --accent:#d98a6a;
    --accent-soft:#2e231c;
    --border:#342a22;
    --topbar-bg:rgba(30,24,20,.92);
    --shadow:0 8px 30px rgba(0,0,0,.35);
  }
  @media (prefers-color-scheme: dark){
    :root:not([data-theme="light"]){
      --bg:#14100d; --paper:#1e1814; --ink:#e9ddd0; --muted:#a08a76; --accent:#d98a6a; --accent-soft:#2e231c; --border:#342a22; --topbar-bg:rgba(30,24,20,.92);
    }
  }
  *{box-sizing:border-box}
  html{scroll-behavior:smooth}
  body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--reader-font);-webkit-font-smoothing:antialiased}
  /* top progress */
  #progressTrack{position:fixed;top:0;left:0;right:0;height:3px;z-index:40;background:transparent}
  #progressBar{height:100%;width:0%;background:var(--accent);transition:width .12s linear}
  /* header */
  header{position:sticky;top:0;z-index:30;background:var(--topbar-bg);backdrop-filter:blur(10px);border-bottom:1px solid var(--border)}
  .header-inner{max-width:860px;margin:0 auto;padding:6px 16px;min-height:52px;display:flex;align-items:center;gap:10px;flex-wrap:wrap;row-gap:6px}
  .book-mark{font-size:15px;letter-spacing:.08em;white-space:nowrap}
  .book-mark span{color:var(--muted);font-size:12px;letter-spacing:.14em;margin-left:6px;font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif}
  .spacer{flex:1}
  .hbtn{appearance:none;border:1px solid var(--border);background:var(--paper);color:var(--ink);height:34px;padding:0 12px;font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:13px;cursor:pointer;display:inline-flex;align-items:center;gap:6px;white-space:nowrap}
  .seg{display:flex;border:1px solid var(--border);background:var(--paper);overflow:hidden}
  .seg button{border:0;background:transparent;color:var(--muted);padding:0 10px;height:34px;font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:13px;cursor:pointer}
  .seg button.active{background:var(--ink);color:var(--paper)}
  /* toc drawer */
  #scrim{position:fixed;inset:0;background:rgba(20,12,6,.42);z-index:35;opacity:0;pointer-events:none;transition:.2s}
  #scrim.open{opacity:1;pointer-events:auto}
  #toc{position:fixed;top:0;left:0;bottom:0;width:min(320px,86vw);background:var(--paper);border-right:1px solid var(--border);z-index:36;transform:translateX(-105%);visibility:hidden;pointer-events:none;transition:transform .25s ease,visibility 0s linear .25s;display:flex;flex-direction:column}
  #toc.open{transform:translateX(0);visibility:visible;pointer-events:auto;transition:transform .25s ease,visibility 0s}
  .toc-head{padding:20px 20px 14px;border-bottom:1px solid var(--border)}
  .toc-head h2{margin:0;font-size:18px;letter-spacing:.1em}
  .toc-head p{margin:6px 0 0;color:var(--muted);font-size:12px;font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;letter-spacing:.08em}
  .toc-list{overflow:auto;padding:8px}
  .toc-item{display:flex;align-items:center;gap:12px;width:100%;text-align:left;border:0;background:transparent;padding:11px 12px;cursor:pointer;color:var(--ink)}
  .toc-item:hover{background:var(--accent-soft)}
  .toc-item.current{background:var(--accent-soft);box-shadow:inset 3px 0 0 var(--accent)}
  .toc-num{font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:11px;color:var(--muted);width:28px;letter-spacing:.06em}
  .toc-term{font-size:16px;letter-spacing:.06em}
  .toc-pct{margin-left:auto;font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:11px;color:var(--muted)}
  [hidden]{display:none!important}
  /* main */
  main{max-width:760px;margin:0 auto;padding:28px 20px 40px}
  .chapter-kicker{text-align:center;color:var(--accent);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:12px;letter-spacing:.28em;margin-top:12px}
  #chTitle{text-align:center;margin:14px 0 6px;font-size:32px;letter-spacing:.14em;font-weight:700;line-height:1.3}
  #chTermSub{text-align:center;color:var(--muted);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:13px;letter-spacing:.18em}
  .ornament{text-align:center;color:var(--accent);letter-spacing:.6em;margin:22px 0 18px;font-size:13px;opacity:.9}
  #content{font-size:var(--fs);line-height:var(--lh);letter-spacing:.02em}
  #content p{margin:0 0 1.05em;text-indent:2em;text-align:justify;word-break:break-word}
  #content p.no-indent{text-indent:0}
  .pov{display:flex;align-items:center;gap:14px;margin:30px 0 20px;color:var(--muted);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:13px;letter-spacing:.3em}
  .pov::before,.pov::after{content:"";flex:1;height:1px;background:var(--border)}
  .pov span{white-space:nowrap}
  .chapter-end{text-align:center;margin:36px 0 8px;color:var(--muted);font-size:13px;letter-spacing:.3em}
  /* cover page */
  .cover-view{display:block;padding:18px 16px 24px;overflow:visible}
  .cover-wrap{width:95%;margin:0 auto;text-align:center;display:flex;flex-direction:column;align-items:center}
  .cover-img{width:100%;height:auto;aspect-ratio:16/9;object-fit:contain;display:block;border:1px solid var(--border);box-shadow:var(--shadow)}
  .cover-cap{margin-top:14px;color:var(--ink);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:15px;letter-spacing:.18em;flex:0 0 auto}
  .cover-cap span{color:var(--muted);font-size:13px}
  .cover-actions{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:14px;flex:0 0 auto}
  .cover-actions button{appearance:none;min-height:40px;padding:0 22px;border:1px solid var(--border);background:var(--paper);color:var(--ink);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:14px;letter-spacing:.08em;cursor:pointer}
  .cover-actions .cover-primary{background:var(--ink);color:var(--paper);border-color:var(--ink)}
  /* chapter nav */
  .chap-nav{display:flex;gap:10px;margin-top:28px}
  .chap-nav button{flex:1;padding:14px 12px;border:1px solid var(--border);background:var(--paper);color:var(--ink);cursor:pointer;font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif}
  .chap-nav button:disabled{opacity:.35;cursor:not-allowed}
  .chap-nav .label{font-size:11px;color:var(--muted);letter-spacing:.14em;display:block;margin-bottom:4px}
  .chap-nav .title{font-size:15px;letter-spacing:.06em}
  .toc-jump{margin-top:10px;width:100%;padding:12px;border:1px dashed var(--border);background:transparent;color:var(--muted);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:13px;letter-spacing:.08em;cursor:pointer}
  /* bottom info */
  .reading-meta{max-width:760px;margin:0 auto;padding:0 20px 28px;display:flex;justify-content:space-between;color:var(--muted);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:12px;letter-spacing:.06em}
  /* footer */
  footer{border-top:1px solid var(--border);padding:18px 20px 28px;text-align:center;color:var(--muted);font-family:-apple-system,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;font-size:12px;letter-spacing:.08em;line-height:1.8}
  @media (max-width:560px){
    .book-mark span{display:none}
    #chTitle{font-size:26px}
    .cover-view{padding:12px 8px 18px}
    .cover-cap{margin-top:10px}
    .cover-actions{margin-top:10px}
  }