:root{
  --bg:#f5f5fb; --card:#ffffff; --ink:#1c2130; --muted:#6b7180; --line:#e7e7f0;
  --accent:#7c3aed; --accent-2:#6d28d9; --accent-3:#2563eb; --accent-soft:#f2eeff;
  --side:#0a0e19; --side-2:#121731; --side-ink:#9aa4c0; --side-line:#202a4d;
  --radius:16px; --shadow:0 1px 2px rgba(20,20,50,.04),0 10px 30px -14px rgba(20,20,60,.22);
  --maxw:830px; --side-w:304px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0; background:var(--bg); color:var(--ink);
  font-family:system-ui,-apple-system,"Segoe UI",Roboto,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  font-size:16px; line-height:1.75; -webkit-font-smoothing:antialiased;
}
a{color:var(--accent-2); text-decoration:none}
a:hover{text-decoration:underline}

/* ---------- progress ---------- */
.progress{position:fixed;top:0;left:0;height:3px;width:0;background:linear-gradient(90deg,#7c3aed,#2563eb,#06b6d4);z-index:60;transition:width .1s linear}

/* ---------- sidebar ---------- */
.sidebar{
  position:fixed;top:0;left:0;bottom:0;width:var(--side-w);z-index:40;
  background:linear-gradient(185deg,var(--side-2),var(--side) 45%);
  color:var(--side-ink); display:flex; flex-direction:column; border-right:1px solid #060911;
}
.sidebar:before{content:"";position:absolute;top:0;left:0;right:0;height:3px;background:linear-gradient(90deg,#7c3aed,#2563eb,#06b6d4)}
.brand{display:flex;align-items:center;gap:12px;padding:22px 18px 14px;position:relative;overflow:hidden}
.brand:after{content:"";position:absolute;right:-10px;bottom:-18px;width:110px;height:110px;
  background:url("logo-white.png") no-repeat center/contain;opacity:.17;pointer-events:none}
.brand-mark{width:40px;height:40px;flex:0 0 40px;border-radius:13px;background:#fff7ed;
  display:flex;align-items:center;justify-content:center;box-shadow:0 6px 16px -6px rgba(0,0,0,.55);overflow:hidden}
.brand-mark img{width:100%;height:100%;object-fit:contain;display:block}
.brand-text{display:flex;flex-direction:column;line-height:1.25}
.brand-title{color:#fff;font-weight:700;font-size:16px}
.brand-title:hover{text-decoration:none}
.brand-sub{color:#68719a;font-size:11.5px}
.search-wrap{padding:4px 14px 12px}
#nav-search,.hero-search input{
  width:100%;padding:10px 13px;border-radius:11px;border:1px solid var(--side-line);
  background:#0e142c;color:#e4e8f5;font-size:14px;outline:none}
#nav-search::placeholder{color:#5b6489}
#nav-search:focus{border-color:var(--accent);box-shadow:0 0 0 3px rgba(124,58,237,.3)}
.nav{overflow-y:auto;padding:4px 12px 20px;flex:1;scrollbar-width:thin;scrollbar-color:#8b5cf6 #0d1230}
.nav::-webkit-scrollbar{width:10px}
.nav::-webkit-scrollbar-track{background:#0d1230;border-radius:8px}
.nav::-webkit-scrollbar-thumb{background:linear-gradient(180deg,#8b5cf6,#6366f1);border-radius:8px;border:2px solid #0d1230;background-clip:padding-box}
.nav::-webkit-scrollbar-thumb:hover{background:linear-gradient(180deg,#a78bfa,#818cf8);background-clip:padding-box}
/* ---------- sidebar accordion (大分类/小分类) ---------- */
.nav-part{margin:0}
.nav-part-title,.nav-cat-title{display:flex;align-items:center;gap:8px;width:100%;text-align:left;
  background:none;border:0;font:inherit;border-radius:10px}
/* 大分类：灰色小标签 + ◤ 色块前缀，不可点击 */
.nav-part-title{padding:15px 10px 7px;font-size:10.5px;font-weight:800;letter-spacing:.11em;color:#8590ad;
  text-transform:uppercase;border-bottom:1px solid var(--side-line);cursor:default}
.nav-part-title::before{content:"";flex:none;width:10px;height:10px;
  background:linear-gradient(135deg,#a78bfa,#4f46e5);clip-path:polygon(0 0,100% 0,0 100%)}
.nav-part-title>span:first-child{flex:1}
/* 小分类：淡紫柔和底按钮 */
.nav-cat{margin:3px 6px}
.nav-cat-title{position:relative;overflow:hidden;padding:9px 12px;font-size:14px;font-weight:700;color:#d9d2fb;cursor:pointer;
  background:rgba(139,92,246,.16);border:1px solid rgba(139,92,246,.26)}
.nav-cat-title:hover{background:rgba(139,92,246,.28);color:#fff;border-color:rgba(167,139,250,.5)}
.nav-cat.open>.nav-cat-title{background:rgba(124,58,237,.30);color:#fff;border-color:rgba(167,139,250,.62)}
.nav-cat-title>span:first-child{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.nav-cat-title::after{content:"";flex:none;width:0;height:0;
  border-left:6px solid #b9a9f7;border-top:5px solid transparent;border-bottom:5px solid transparent;
  transition:transform .15s ease;opacity:.95}
.nav-cat.open>.nav-cat-title::after{transform:rotate(90deg);border-left-color:#fff}
/* 悬停提示 */
.nav-cat-title::before{content:"点击展开 ▾";position:absolute;right:28px;top:50%;transform:translateY(-50%);
  font-size:11px;font-weight:700;color:rgba(255,255,255,.88);white-space:nowrap;
  opacity:0;transition:opacity .12s ease;pointer-events:none}
.nav-cat-title:hover::before{opacity:1}
.nav-cat.open>.nav-cat-title::before{content:"点击收起 ▴"}
.nav-cat-title:hover .nav-n{opacity:0}
.nav-part-body{display:block}
.nav-list{display:none;margin:4px 0 8px}
.nav-cat.open>.nav-list{display:block}
.nav-n{flex:none;font-size:11.5px;font-weight:700;color:rgba(216,208,250,.8);transition:opacity .12s ease}
.nav-part-title .nav-n{color:#6b76a0;font-weight:600}
.nav.searching .nav-part-body,.nav.searching .nav-list{display:block}
.nav-list{list-style:none;margin:5px 0 8px;padding:0 0 0 8px}
.nav-link{display:block;padding:6px 12px;border-radius:9px;color:#aab3cf;font-size:14px;border-left:2px solid transparent}
.nav-link:hover{background:#161d3a;color:#fff;text-decoration:none}
.nav-link.active{background:linear-gradient(90deg,rgba(124,58,237,.32),rgba(37,99,235,.16));color:#fff;border-left-color:#a78bfa;font-weight:600}
.nav-link.hide{display:none}
.side-foot{padding:12px 18px;border-top:1px solid var(--side-line);color:#4d5779;font-size:12px}

/* ---------- mobile ---------- */
.nav-toggle{display:none}
.nav-btn{display:none}
@media (max-width:1000px){
  .sidebar{transform:translateX(-100%);transition:transform .25s ease;box-shadow:0 0 50px rgba(0,0,0,.5)}
  .nav-toggle:checked ~ .sidebar{transform:translateX(0)}
  .nav-btn{display:flex;flex-direction:column;gap:4px;position:fixed;top:14px;left:14px;z-index:50;
    width:44px;height:44px;border-radius:13px;background:#121731;align-items:center;justify-content:center;cursor:pointer;box-shadow:var(--shadow)}
  .nav-btn span{display:block;width:20px;height:2px;background:#dbe0f0;border-radius:2px}
  .content{margin-left:0 !important;padding:60px 18px 50px}
}

/* ---------- content ---------- */
.content{margin-left:var(--side-w);padding:36px 40px 64px 28px;min-height:100vh}
.article,.hero,.chapters,.allterms,footer.site-foot,.pager,.related,.crumbs{max-width:var(--maxw);margin-left:0;margin-right:auto}
.crumbs{margin-bottom:16px;color:var(--muted);font-size:13.5px}
.crumbs a{color:var(--muted)}
.crumbs em{font-style:normal;color:var(--ink)}
h1{font-size:31px;line-height:1.35;margin:0 0 14px;letter-spacing:-.015em}
.meta{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:14px}
.tag{display:inline-block;background:var(--accent-soft);color:var(--accent-2);font-size:12.5px;font-weight:600;padding:4px 11px;border-radius:999px}
.tag-q{background:#eaf1ff;color:var(--accent-3)}
.lead{font-size:18px;color:#3a4152;background:var(--card);border:1px solid var(--line);border-left:4px solid var(--accent);
  padding:16px 18px;border-radius:12px;margin:0 0 26px}

/* ---------- TOC ---------- */
.toc{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px 18px;margin:0 0 28px;box-shadow:var(--shadow)}
.toc-title{font-weight:700;font-size:13.5px;color:var(--muted);letter-spacing:.05em;margin-bottom:8px}
.toc ul{list-style:none;margin:0;padding:0}
.toc li{margin:3px 0}
.toc li.toc-h3{padding-left:16px;font-size:14.5px}
.toc a{color:#3a4152}
.toc a:hover{color:var(--accent-2)}

/* ---------- prose ---------- */
.prose{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);
  padding:30px 36px;font-size:16.5px;line-height:1.92;color:#242a38}
.prose h2{font-size:23px;margin:2em 0 .7em;padding-bottom:.35em;border-bottom:1px solid var(--line);letter-spacing:-.01em;scroll-margin-top:24px}
.prose h3{font-size:19px;margin:1.7em 0 .55em;scroll-margin-top:24px}
.prose h4{font-size:16.5px;margin:1.3em 0 .5em;color:#3a4152;scroll-margin-top:24px}
.prose h2:first-child,.prose h3:first-child{margin-top:0}
.prose p{margin:0 0 1.15em}
.prose ul,.prose ol{margin:0 0 1.2em;padding-left:1.4em}
.prose li{margin:.4em 0}
.prose strong{color:#111827}
.prose a{border-bottom:1px solid rgba(124,58,237,.4)}
.prose a:hover{text-decoration:none;background:var(--accent-soft)}
.prose blockquote{margin:1.4em 0;padding:14px 20px;background:#f8f7fd;border-left:4px solid #c4b5fd;border-radius:0 12px 12px 0;color:#4a4f61}
.prose blockquote p{margin:0}
.prose code{background:#f4f2fb;border:1px solid #e6e2f5;border-radius:6px;padding:2px 6px;font-size:.9em;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;color:#9333ea}
.table-wrap{overflow-x:auto;margin:1.4em 0}
.prose table{border-collapse:collapse;width:100%;font-size:15px}
.prose th,.prose td{border:1px solid var(--line);padding:9px 12px;text-align:left}
.prose th{background:#f8f7fd;font-weight:700}
.fig{margin:1.6em 0;text-align:center}
.fig img{max-width:100%;height:auto;border:1px solid var(--line);border-radius:12px;box-shadow:var(--shadow);background:#fff}
.fig figcaption{margin-top:8px;color:var(--muted);font-size:13.5px}

/* ---------- pager / related ---------- */
.pager{display:flex;justify-content:space-between;gap:14px;margin:34px 0}
.pg{flex:1;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:14px 18px;box-shadow:var(--shadow)}
.pg:hover{text-decoration:none;border-color:#c4b5fd}
.pg span{display:block;font-size:12.5px;color:var(--muted);margin-bottom:3px}
.pg strong{font-size:15.5px;color:var(--ink)}
.pg.next{text-align:right}
.related{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px 18px;margin:0 0 30px}
.related-title{font-weight:700;font-size:13.5px;color:var(--muted);margin-bottom:10px}
.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{display:inline-block;background:#f4f4fb;border:1px solid var(--line);color:#3a4152;padding:6px 12px;border-radius:999px;font-size:13.5px}
.chip:hover{background:var(--accent-soft);border-color:#ddd6fe;color:var(--accent-2);text-decoration:none}

/* ---------- index hero ---------- */
.hero{background:radial-gradient(120% 140% at 85% -10%,#3b1d78 0,#141a3a 45%,#0a0e19 100%);color:#fff;border-radius:22px;padding:48px 44px;margin-bottom:30px;position:relative;overflow:hidden}
.hero:after{content:"";position:absolute;right:-90px;top:-90px;width:300px;height:300px;border-radius:50%;background:radial-gradient(circle,rgba(124,58,237,.6),transparent 68%)}
.hero-kicker{font-size:12.5px;letter-spacing:.16em;text-transform:uppercase;color:#a5b4fc;font-weight:700;margin-bottom:12px}
.hero-title{font-size:42px;margin:0 0 12px;letter-spacing:-.02em}
.hero-sub{color:#c3cbe4;max-width:660px;margin:0 0 20px;font-size:16.5px}
.hero-stats{display:flex;gap:22px;flex-wrap:wrap;color:#9fb0d4;font-size:14px;margin-bottom:22px}
.hero-stats b{color:#fff;font-size:18px}
.hero-search{position:relative;max-width:560px}
.hero-search input{background:#fff;color:#12172b;border:none;padding:14px 16px;border-radius:12px;font-size:15px;width:100%}
.hero-results{position:absolute;z-index:20;left:0;right:0;top:60px;background:#fff;border-radius:12px;box-shadow:0 24px 60px -14px rgba(2,8,23,.55);overflow:hidden;display:none}
.hero-results.show{display:block}
.hero-results a{display:flex;justify-content:space-between;gap:10px;padding:11px 15px;color:#1c2130;border-bottom:1px solid #f1f1f7}
.hero-results a:last-child{border-bottom:none}
.hero-results a:hover{background:var(--accent-soft);text-decoration:none}
.hero-results .hr-ch{color:var(--muted);font-size:12.5px}

/* ---------- chapters ---------- */
.chapters{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:16px;margin-bottom:34px}
.chapter-card{display:block;background:var(--card);border:1px solid var(--line);border-radius:18px;padding:20px;box-shadow:var(--shadow);color:inherit;transition:transform .15s ease,border-color .15s ease}
.chapter-card:hover{transform:translateY(-3px);border-color:#c4b5fd;text-decoration:none}
.cc-head{display:flex;justify-content:flex-end}
.cc-count{font-size:12px;color:var(--accent-2);background:var(--accent-soft);padding:3px 10px;border-radius:999px;font-weight:600}
.cc-title{font-size:19px;font-weight:700;margin:6px 0 6px}
.cc-desc{color:var(--muted);font-size:13.5px;margin-bottom:12px}
.cc-terms{color:#666e85;font-size:13px;border-top:1px dashed var(--line);padding-top:10px}

/* ---------- all terms ---------- */
.sec-title{font-size:24px;margin:0 0 18px}
.at-group{margin-bottom:22px}
.at-group h3{font-size:16px;margin:0 0 10px;color:#3a4152;display:flex;align-items:center;gap:10px}
.at-group h3:before{content:"";width:6px;height:18px;background:linear-gradient(180deg,#7c3aed,#2563eb);border-radius:3px;display:inline-block}
.at-n{font-size:12px;color:#8a90a6;font-weight:600}

/* ---------- footer ---------- */
.site-foot{margin:40px 0 0;padding-top:22px;border-top:1px solid var(--line);color:var(--muted);font-size:13px;text-align:left}
.site-foot p{margin:4px 0}

/* ---------- ads ---------- */
.ad{display:block;max-width:830px;margin:0 0 22px;line-height:0;border-radius:14px;transition:opacity .15s}
.ad img{width:100%;height:auto;display:block;border-radius:14px}
.ad:hover{opacity:.94}
.ad-bottom{margin:34px 0 0}
.ad-slot{display:block;max-width:830px;line-height:0;border-radius:14px}
.ad-slot[data-pos="top"]{min-height:90px;margin:0 0 22px}
.ad-slot[data-pos="bottom"]{min-height:120px;margin:34px 0 0}
.ad-slot a{display:block;line-height:0}
.ad-slot img{width:100%;height:auto;display:block;border-radius:14px;transition:opacity .15s}
.ad-slot a:hover img{opacity:.94}

/* ---------- category page ---------- */
.catgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(248px,1fr));gap:14px;margin-top:6px}
.catcard{display:block;background:var(--card);border:1px solid var(--line);border-radius:14px;padding:16px 18px;box-shadow:var(--shadow);color:inherit}
.catcard:hover{transform:translateY(-2px);border-color:#c4b5fd;text-decoration:none}
.cc-title2{font-size:16.5px;font-weight:700;margin-bottom:6px}
.cc-sum{color:var(--muted);font-size:13px;line-height:1.6}

/* ---------- index：大分类标题 ---------- */
.chapters .part-line{grid-column:1/-1;margin:22px 0 2px;font-size:13.5px;font-weight:800;color:var(--accent-2);
  border-left:3px solid var(--accent);padding-left:10px;letter-spacing:.02em}
.chapters .part-line:first-child{margin-top:0}
.part-h2{font-size:19px;margin:30px 0 14px;padding-left:10px;border-left:4px solid var(--accent)}