:root {
    --bg: #f4f6fb;
    --bg-soft: #ffffff;
    --panel: rgba(15, 23, 42, 0.04);
    --panel-2: rgba(15, 23, 42, 0.07);
    --line: rgba(15, 23, 42, 0.1);
    --line-strong: rgba(15, 23, 42, 0.2);
    --txt: #0f172a;
    --txt-soft: #334155;
    --muted: #64748b;
    --cyan: #0891b2;
    --blue: #2563eb;
    --indigo: #4f46e5;
    --violet: #7c3aed;
    --green: #059669;
    --amber: #d97706;
    --red: #dc2626;
    --grad: linear-gradient(100deg, #06b6d4 0%, #2563eb 55%, #4f46e5 100%);
    --radius: 16px;
    --mono: ui-monospace, SFMono-Regular, 'Cascadia Code', Consolas, Menlo, monospace;
  }
  * { margin: 0; padding: 0; box-sizing: border-box; }
  html { scroll-behavior: smooth; }
  body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC',
      'Hiragino Sans GB', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
    background: var(--bg);
    color: var(--txt);
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
  }
  /* 科技背景：网格 + 光晕 */
  body::before {
    content: '';
    position: fixed; inset: 0; z-index: -2; pointer-events: none;
    background:
      radial-gradient(60rem 40rem at 8% -10%, rgba(6, 182, 212, 0.14), transparent 60%),
      radial-gradient(50rem 36rem at 95% 5%, rgba(79, 70, 229, 0.14), transparent 60%),
      radial-gradient(46rem 42rem at 50% 110%, rgba(6, 182, 212, 0.08), transparent 60%);
  }
  body::after {
    content: '';
    position: fixed; inset: 0; z-index: -1; pointer-events: none;
    background-image:
      linear-gradient(rgba(15, 23, 42, 0.05) 1px, transparent 1px),
      linear-gradient(90deg, rgba(15, 23, 42, 0.05) 1px, transparent 1px);
    background-size: 44px 44px;
    mask-image: radial-gradient(ellipse 90% 70% at 50% 0%, #000 20%, transparent 78%);
    -webkit-mask-image: radial-gradient(ellipse 90% 70% at 50% 0%, #000 20%, transparent 78%);
  }
  a { text-decoration: none; color: inherit; }
  img { max-width: 100%; }
  .wrap { max-width: 1180px; margin: 0 auto; padding: 0 24px; }

  /* ===== 顶部滚动进度条 ===== */
  .scroll-progress {
    position: fixed; top: 0; left: 0; height: 3px; width: 0%;
    background: var(--grad); z-index: 200;
    box-shadow: 0 0 12px rgba(34, 211, 238, 0.6);
  }

  /* ===== 导航 ===== */
  /* sticky 挂在 header 上：挂 .nav-bar 会被 .site-nav 的高度限制住，滚出父元素即失效 */
  .site-nav {
    position: sticky; top: 0; z-index: 120;
    background: transparent;
    transition: background 0.28s, box-shadow 0.28s, backdrop-filter 0.28s;
  }
  /* 滚动后浮现毛玻璃：避免正文穿过时出现重影、看不清 */
  .site-nav.is-solid {
    background: rgba(255, 255, 255, 0.72);
    -webkit-backdrop-filter: blur(14px);
    backdrop-filter: blur(14px);
    box-shadow: 0 1px 0 var(--line);
  }
  .site-nav.is-solid .cat-bar { border-bottom-color: transparent; }
  .nav-bar {
    display: flex; align-items: center; justify-content: space-between; gap: 20px;
    padding: 14px 24px;
  }
  .brand {
    font-size: 19px; font-weight: 800; letter-spacing: 0.2px;
    display: inline-flex; align-items: center; gap: 8px; white-space: nowrap;
  }
  .brand .bolt {
    width: 30px; height: 30px; border-radius: 9px;
    display: inline-flex; align-items: center; justify-content: center;
    background: var(--grad); color: #fff; font-size: 15px;
    box-shadow: 0 0 16px rgba(6, 182, 212, 0.4);
  }
  .brand b { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
  .nav-links { display: flex; align-items: center; gap: 4px; flex-wrap: wrap; }
  .nav-links a {
    font-size: 14px; color: var(--muted); padding: 7px 13px; border-radius: 9px;
    transition: color 0.2s, background 0.2s;
  }
  .nav-links a:hover { color: var(--txt); background: var(--panel-2); }
  .nav-links a.on { color: var(--cyan); }

  /* 分类导航条 */
  .cat-bar {
    border-bottom: 1px solid var(--line);
    background: transparent;
  }
  .cat-bar .wrap {
    display: flex; align-items: center; gap: 8px;
    padding-top: 10px; padding-bottom: 10px; overflow-x: auto;
    scrollbar-width: none;
  }
  .cat-bar .wrap::-webkit-scrollbar { display: none; }
  .cat-chip {
    flex: 0 0 auto; display: inline-flex; align-items: center; gap: 6px;
    font-size: 13px; color: var(--muted);
    border: 1px solid var(--line); border-radius: 999px;
    padding: 5px 14px;
    transition: all 0.2s;
    background: transparent;
  }
  .cat-chip:hover { color: var(--txt); border-color: var(--line-strong); background: var(--panel-2); }
  .cat-chip.is-active {
    color: #fff; font-weight: 600;
    background: var(--grad); border-color: transparent;
    box-shadow: 0 0 18px rgba(37, 99, 235, 0.3);
  }

  /* ===== Hero ===== */
  .hero {
    position: relative; text-align: center;
    padding: 92px 24px 76px;
  }
  .hero .hero-glow {
    position: absolute; left: 50%; top: 40px; transform: translateX(-50%);
    width: 620px; height: 340px; z-index: -1; pointer-events: none;
    background: radial-gradient(closest-side, rgba(6, 182, 212, 0.2), transparent);
    filter: blur(10px);
    animation: heroPulse 6s ease-in-out infinite;
  }
  .hero h1 { color: #0f172a; }
  @keyframes heroPulse { 0%,100% { opacity: 0.65; } 50% { opacity: 1; } }
  .hero-eyebrow {
    font-family: var(--mono); font-size: 13px; letter-spacing: 3px;
    color: var(--cyan);
    display: inline-flex; align-items: center; gap: 10px;
    margin-bottom: 22px;
  }
  .hero-eyebrow::before, .hero-eyebrow::after {
    content: ''; width: 34px; height: 1px;
    background: linear-gradient(90deg, transparent, rgba(34, 211, 238, 0.7), transparent);
  }
  .hero h1 {
    font-size: clamp(32px, 5.4vw, 58px);
    font-weight: 800; line-height: 1.25; letter-spacing: 1px;
    margin: 0 auto 20px; max-width: 880px;
  }
  .hero h1 .grad {
    background: var(--grad);
    -webkit-background-clip: text; background-clip: text; color: transparent;
  }
  .hero-sub {
    max-width: 660px; margin: 0 auto 30px;
    font-size: 16.5px; color: var(--muted);
  }
  .hero-actions { display: flex; justify-content: center; gap: 14px; flex-wrap: wrap; }
  .btn {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 12px 26px; border-radius: 12px;
    font-size: 15px; font-weight: 600;
    transition: all 0.2s; border: 1px solid transparent; cursor: pointer;
  }
  .btn-primary {
    background: var(--grad); color: #fff;
    box-shadow: 0 4px 24px rgba(37, 99, 235, 0.26);
  }
  .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 32px rgba(37, 99, 235, 0.4); }
  .btn-ghost { color: var(--txt-soft); border-color: var(--line-strong); background: rgba(255, 255, 255, 0.6); }
  .btn-ghost:hover { border-color: var(--cyan); color: var(--cyan); transform: translateY(-2px); }
  .hero-stats {
    margin-top: 46px; display: flex; justify-content: center; gap: 44px; flex-wrap: wrap;
  }
  .hstat { text-align: center; }
  .hstat .num {
    font-family: var(--mono); font-size: 26px; font-weight: 700;
    background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent;
  }
  .hstat .lab { font-size: 12.5px; color: var(--muted); letter-spacing: 1px; }
  .hero .scroll-hint {
    margin-top: 52px; font-family: var(--mono); font-size: 12px; color: var(--muted);
    letter-spacing: 2px; display: inline-flex; align-items: center; gap: 8px;
  }
  .hero .scroll-hint::after {
    content: ''; width: 1px; height: 30px; display: inline-block;
    background: linear-gradient(var(--cyan), transparent);
    animation: dropHint 1.8s ease-in-out infinite;
  }
  @keyframes dropHint { 0% { transform: scaleY(0.4); opacity: 0.6; } 60% { transform: scaleY(1); opacity: 1; } 100% { transform: translateY(6px) scaleY(0.3); opacity: 0.2; } }

  /* ===== 内容区通用 ===== */
  .feed { max-width: 1180px; margin: 0 auto; padding: 18px 24px 70px; }
  .cat-section { scroll-margin-top: 128px; margin-bottom: 54px; }
  .s-head { display: flex; align-items: flex-end; gap: 14px; margin-bottom: 26px; flex-wrap: wrap; }
  .s-head .icon {
    width: 52px; height: 52px; border-radius: 14px; flex: 0 0 auto;
    display: inline-flex; align-items: center; justify-content: center; font-size: 25px;
    border: 1px solid var(--line-strong);
    background: linear-gradient(150deg, rgba(6, 182, 212, 0.18), rgba(79, 70, 229, 0.1));
    box-shadow: inset 0 0 18px rgba(6, 182, 212, 0.12);
  }
  .s-head .s-title { font-size: 26px; font-weight: 800; letter-spacing: 0.5px; }
  .s-head .s-title .grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
  .s-head .s-desc { font-size: 14px; color: var(--muted); margin-top: 3px; max-width: 640px; }
  .s-head .s-tag {
    margin-left: auto; align-self: center; font-family: var(--mono); font-size: 12.5px;
    color: var(--muted); border: 1px dashed var(--line-strong); border-radius: 999px; padding: 4px 13px;
    white-space: nowrap;
  }

  .card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
  }
  /* 单篇文章的分类：卡片限宽，避免 auto-fit 拉满整行 */
  .cat-section.is-single .card-grid { grid-template-columns: minmax(0, 480px); }

  .post-card {
    min-width: 0;
    position: relative;
    display: flex; flex-direction: column;
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    overflow: hidden;
    transition: transform 0.25s, border-color 0.25s, box-shadow 0.25s;
    box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04), 0 10px 28px -18px rgba(15, 23, 42, 0.18);
  }
  .post-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0; height: 2px;
    background: var(--grad); opacity: 0; transition: opacity 0.25s;
  }
  .post-card:hover {
    transform: translateY(-5px);
    border-color: rgba(6, 182, 212, 0.5);
    box-shadow: 0 16px 44px -14px rgba(37, 99, 235, 0.28), 0 4px 14px -6px rgba(15, 23, 42, 0.1);
  }
  .post-card:hover::before { opacity: 1; }
  .post-card .p-icon {
    width: 100%; height: 140px; flex: 0 0 auto;
    display: inline-flex; align-items: center; justify-content: center; font-size: 48px;
    border-radius: 0;
  }
  .cover-1 { background: linear-gradient(150deg, rgba(6, 182, 212, 0.2), rgba(37, 99, 235, 0.08)); box-shadow: inset 0 0 20px rgba(6, 182, 212, 0.12); }
  .cover-2 { background: linear-gradient(150deg, rgba(37, 99, 235, 0.22), rgba(79, 70, 229, 0.1)); box-shadow: inset 0 0 20px rgba(37, 99, 235, 0.16); }
  .cover-3 { background: linear-gradient(150deg, rgba(5, 150, 105, 0.2), rgba(6, 182, 212, 0.08)); box-shadow: inset 0 0 20px rgba(5, 150, 105, 0.14); }
  .cover-4 { background: linear-gradient(150deg, rgba(124, 58, 237, 0.22), rgba(79, 70, 229, 0.12)); box-shadow: inset 0 0 20px rgba(124, 58, 237, 0.18); }
  .p-body { padding: 20px 24px 24px; display: flex; flex-direction: column; flex: 1 1 auto; gap: 10px; }
  .p-meta { display: flex; align-items: center; gap: 12px; font-family: var(--mono); font-size: 12px; color: var(--muted); }
  .p-meta .dot { width: 3px; height: 3px; border-radius: 50%; background: var(--line-strong); }
  .p-meta .cat-pill {
    color: var(--cyan); border: 1px solid rgba(8, 145, 178, 0.35);
    padding: 0 9px; border-radius: 999px; font-size: 11.5px; line-height: 1.7;
  }
  .post-card h3 {
    font-size: 18px; font-weight: 700; line-height: 1.5; transition: color 0.2s;
    display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
    min-height: 54px;
  }
  .post-card:hover h3 { color: var(--cyan); }
  .p-body p { font-size: 14px; color: var(--muted); line-height: 1.65;
    display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden;
    min-height: 69px;
  }
  .p-tags { display: flex; flex-wrap: wrap; gap: 7px; }
  .p-tags span {
    font-size: 12px; color: var(--txt-soft);
    border: 1px solid var(--line); border-radius: 6px; padding: 1px 8px;
    background: rgba(15, 23, 42, 0.04);
  }
  .p-foot { margin-top: auto; display: flex; align-items: center; justify-content: space-between; padding-top: 6px; border-top: 1px solid var(--line); }
  .p-foot .go {
    font-family: var(--mono); font-size: 12.5px; color: var(--cyan); font-weight: 600;
    display: inline-flex; align-items: center; gap: 6px;
  }
  .p-foot .go i { font-style: normal; transition: transform 0.2s; }
  .post-card:hover .go i { transform: translateX(4px); }
  .p-foot .time { font-size: 12px; color: var(--muted); font-family: var(--mono); }

  /* 空状态 */
  .empty-tip { display: none; text-align: center; padding: 60px 0; color: var(--muted); font-size: 15px; }
  .empty-tip.show { display: block; }

  /* ===== 学习路径 ===== */
  .learn-path {
    position: relative;
    border: 1px solid var(--line);
    border-radius: 22px;
    padding: 44px 40px;
    background:
      radial-gradient(40rem 22rem at 100% 0%, rgba(79, 70, 229, 0.08), transparent 60%),
      radial-gradient(34rem 20rem at 0% 100%, rgba(6, 182, 212, 0.08), transparent 60%),
      #ffffff;
    margin: 8px 0 72px;
    overflow: hidden;
  }
  .learn-path::after {
    content: ''; position: absolute; inset: 0; pointer-events: none;
    background-image:
      linear-gradient(rgba(15, 23, 42, 0.05) 1px, transparent 1px),
      linear-gradient(90deg, rgba(15, 23, 42, 0.05) 1px, transparent 1px);
    background-size: 32px 32px;
    mask-image: radial-gradient(ellipse 70% 90% at 50% 50%, #000, transparent 75%);
    -webkit-mask-image: radial-gradient(ellipse 70% 90% at 50% 50%, #000, transparent 75%);
  }
  .learn-path .wrap-inner { position: relative; z-index: 1; }
  .learn-path .lp-title { font-size: 24px; font-weight: 800; text-align: center; }
  .learn-path .lp-title .grad { background: var(--grad); -webkit-background-clip: text; background-clip: text; color: transparent; }
  .learn-path .lp-sub { text-align: center; color: var(--muted); font-size: 14.5px; margin: 8px auto 34px; max-width: 620px; }
  .steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 18px; }
  .step {
    border: 1px solid var(--line); border-radius: 14px; padding: 22px;
    background: rgba(255, 255, 255, 0.92); box-shadow: 0 1px 2px rgba(15, 23, 42, 0.04);
    transition: transform 0.25s, border-color 0.25s;
  }
  .step:hover { transform: translateY(-4px); border-color: rgba(34, 211, 238, 0.4); }
  .step .num {
    font-family: var(--mono); font-size: 12px; letter-spacing: 2px; color: var(--cyan);
  }
  .step h4 { font-size: 17px; margin: 8px 0 6px; }
  .step p { font-size: 13.5px; color: var(--muted); margin-bottom: 14px; }
  .step a {
    font-size: 13.5px; color: var(--cyan); display: inline-flex; align-items: center; gap: 6px;
  }
  .step a i { font-style: normal; transition: transform 0.2s; }
  .step a:hover i { transform: translateX(4px); }

  /* ===== 页脚 ===== */
  .footer {
    border-top: 1px solid var(--line);
    background: rgba(255, 255, 255, 0.75);
    padding: 34px 24px 40px; text-align: center;
    font-size: 13px; color: var(--muted);
  }
  .footer .f-links { display: flex; justify-content: center; flex-wrap: wrap; gap: 6px 22px; margin-bottom: 12px; }
  .footer .f-links a { color: var(--txt-soft); transition: color 0.2s; }
  .footer .f-links a:hover { color: var(--cyan); }
  .footer .f-beian a { color: var(--muted); }
  .footer .f-beian a:hover { color: var(--cyan); }
  .footer .f-slogan { margin-top: 12px; font-family: var(--mono); font-size: 12px; letter-spacing: 2px; }

  /* ============================================================
     文章详情页
     ============================================================ */
  .article-layout {
    max-width: 1180px; margin: 0 auto;
    padding: 46px 24px 20px;
    display: flex; gap: 40px; justify-content: center; align-items: flex-start;
  }
  .article-main { flex: 1 1 0; max-width: 860px; min-width: 0; }
  .article-hero { margin-bottom: 34px; }
  .article-route {
    font-family: var(--mono); font-size: 12.5px; color: var(--muted);
    letter-spacing: 1.5px; margin-bottom: 16px;
    display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  }
  .article-route a { color: var(--cyan); }
  .article-route a:hover { text-decoration: underline; }
  .article-hero h1 {
    font-size: clamp(26px, 4vw, 40px);
    font-weight: 800; line-height: 1.35; letter-spacing: 0.3px;
    margin-bottom: 18px;
  }
  .article-hero h1 .grad {
    background: var(--grad);
    -webkit-background-clip: text; background-clip: text; color: transparent;
  }
  .article-meta {
    display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
    font-family: var(--mono); font-size: 13px; color: var(--muted);
    margin-bottom: 18px;
  }
  .article-meta .cat {
    color: var(--cyan); border: 1px solid rgba(34, 211, 238, 0.35);
    padding: 0 11px; border-radius: 999px; font-size: 12px;
  }
  .article-meta .dot { width: 3px; height: 3px; border-radius: 50%; background: var(--line-strong); }
  .article-tags { display: flex; flex-wrap: wrap; gap: 8px; }
  .article-tags span {
    font-size: 12.5px; color: var(--txt-soft);
    border: 1px solid var(--line); border-radius: 7px;
    padding: 2px 11px; background: var(--panel);
  }

  .prose {
    background: #ffffff;
    border: 1px solid var(--line);
    border-radius: 20px;
    padding: 42px 46px 50px;
    font-size: 16.5px; color: var(--txt-soft); line-height: 1.95;
  }
  .prose > *:first-child { margin-top: 0; }
  .prose p { margin: 0 0 18px; }
  .prose h2 {
    font-size: 25px; font-weight: 800; color: var(--txt);
    margin: 48px 0 18px; padding: 4px 0 4px 16px;
    border-left: 3px solid transparent;
    border-image: linear-gradient(180deg, var(--cyan), var(--indigo)) 1;
    scroll-margin-top: 96px;
  }
  .prose h3 {
    font-size: 19.5px; font-weight: 700; color: var(--txt);
    margin: 34px 0 12px;
  }
  .prose h3::before { content: '◆ '; color: var(--cyan); font-size: 13px; vertical-align: 2px; }
  .prose ul, .prose ol { margin: 0 0 20px; padding-left: 24px; }
  .prose li { margin-bottom: 9px; }
  .prose li::marker { color: var(--cyan); }
  .prose strong { color: #0f172a; font-weight: 700; }
  .prose a {
    color: var(--cyan); border-bottom: 1px dashed rgba(8, 145, 178, 0.5);
    transition: border-color 0.2s;
  }
  .prose a:hover { border-bottom-style: solid; }
  .prose table {
    width: 100%; border-collapse: collapse; margin: 22px 0; font-size: 14.5px;
    display: block; overflow-x: auto;
  }
  .prose th, .prose td {
    border: 1px solid var(--line); padding: 10px 14px; text-align: left;
    white-space: nowrap;
  }
  .prose td { color: var(--txt-soft); }
  .prose th {
    background: linear-gradient(180deg, rgba(6, 182, 212, 0.12), rgba(6, 182, 212, 0.04));
    color: #0e7490; font-weight: 600; letter-spacing: 0.3px;
  }
  .prose tr:nth-child(even) td { background: rgba(15, 23, 42, 0.03); }
  .prose pre {
    background: #f8fafc; border: 1px solid #e2e8f0;
    border-radius: 12px; padding: 18px 20px; margin: 20px 0;
    overflow-x: auto; position: relative;
  }
  .prose pre code {
    font-family: var(--mono); font-size: 13.5px; line-height: 1.8; color: #334155;
  }
  .prose code {
    font-family: var(--mono); font-size: 13.5px;
    background: rgba(8, 145, 178, 0.08); border: 1px solid rgba(8, 145, 178, 0.15);
    border-radius: 5px; padding: 1px 6px; color: #0e7490;
  }
  .prose pre code { background: none; border: 0; padding: 0; color: inherit; }
  .prose blockquote {
    border-left: 3px solid var(--cyan);
    background: rgba(6, 182, 212, 0.04);
    padding: 14px 20px; margin: 20px 0; border-radius: 0 10px 10px 0;
    color: var(--txt-soft);
  }
  .tip, .warn, .info {
    border-radius: 12px; padding: 15px 19px; margin: 22px 0; font-size: 15px;
    display: flex; gap: 11px; align-items: flex-start;
  }
  .tip { background: rgba(6, 182, 212, 0.06); border: 1px solid rgba(6, 182, 212, 0.25); }
  .tip::before { content: '💡'; flex: 0 0 auto; }
  .info { background: rgba(79, 70, 229, 0.05); border: 1px solid rgba(79, 70, 229, 0.2); }
  .info::before { content: '📌'; flex: 0 0 auto; }
  .warn { background: rgba(217, 119, 6, 0.05); border: 1px solid rgba(217, 119, 6, 0.2); }
  .warn::before { content: '⚠️'; flex: 0 0 auto; }
  .quiz {
    background: rgba(15, 23, 42, 0.03); border: 1px dashed rgba(15, 23, 42, 0.15);
    border-radius: 12px; padding: 14px 19px; margin: 14px 0;
  }
  .quiz p { margin-bottom: 6px; }
  .quiz p:last-child { margin-bottom: 0; }
  .quiz .ans { color: var(--green); }
  .prose .divider {
    display: block; height: 1px; margin: 34px 0; border: 0;
    background: linear-gradient(90deg, transparent, var(--line-strong), transparent);
  }
  .prose .lead {
    font-size: 17.5px; color: #1e293b;
    border-bottom: 1px solid var(--line); padding-bottom: 20px; margin-bottom: 26px;
  }
  .prose .kbd {
    font-family: var(--mono); font-size: 13px; color: #0e7490;
    background: rgba(8, 145, 178, 0.08); border: 1px solid rgba(8, 145, 178, 0.2);
    border-bottom-width: 3px; border-radius: 6px; padding: 1px 7px; white-space: nowrap;
  }

  /* 侧栏目录 */
  .article-side {
    position: sticky; top: 150px;
    flex: 0 0 240px; min-width: 0;
    display: none;
  }
  .toc-box {
    border: 1px solid var(--line); border-radius: 14px;
    background: rgba(255, 255, 255, 0.8);
    padding: 18px 16px; font-size: 13.5px;
  }
  .toc-box .toc-title {
    font-family: var(--mono); font-size: 11.5px; letter-spacing: 2px; color: var(--muted);
    margin-bottom: 10px; display: flex; align-items: center; gap: 8px;
  }
  .toc-box .toc-title::after { content: ''; flex: 1; height: 1px; background: var(--line); }
  .toc-box nav { display: flex; flex-direction: column; gap: 3px; max-height: 56vh; overflow-y: auto; scrollbar-width: thin; }
  .toc-box nav a {
    padding: 5px 9px; border-radius: 7px; color: var(--muted);
    border-left: 2px solid transparent;
    line-height: 1.55; transition: all 0.18s;
  }
  .toc-box nav a:hover { color: var(--txt); background: var(--panel-2); }
  .toc-box nav a.is-active { color: var(--cyan); border-left-color: var(--cyan); background: rgba(34, 211, 238, 0.07); }
  .toc-box .toc-lv2 { padding-left: 8px; }

  /* 文章底部：相关阅读 */
  .article-foot { margin-top: 34px; }
  .article-foot .af-title {
    font-family: var(--mono); font-size: 12.5px; letter-spacing: 2.5px;
    color: var(--muted); margin-bottom: 16px; display: flex; align-items: center; gap: 12px;
  }
  .article-foot .af-title::after { content: ''; flex: 1; height: 1px; background: var(--line); }
  .rel-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
  .rel-card {
    border: 1px solid var(--line); border-radius: 14px; padding: 18px 20px;
    background: #ffffff;
    transition: all 0.22s; display: flex; flex-direction: column;
  }
  .rel-card:hover { transform: translateY(-3px); border-color: rgba(34, 211, 238, 0.4); }
  .rel-card .r-meta { font-family: var(--mono); font-size: 11.5px; color: var(--muted); margin-bottom: 8px; }
  .rel-card .r-meta span { color: var(--cyan); }
  .rel-card h4 { font-size: 15.5px; line-height: 1.55; margin-bottom: 8px; }
  .rel-card p { font-size: 13px; color: var(--muted); }
  .rel-card .r-go { margin-top: auto; padding-top: 10px; font-family: var(--mono); font-size: 12.5px; color: var(--cyan); }
  .article-back {
    margin-top: 26px; display: inline-flex; align-items: center; gap: 8px;
    font-size: 14px; color: var(--muted); transition: color 0.2s;
  }
  .article-back:hover { color: var(--cyan); }

  /* ===== 响应式 ===== */
  @media (min-width: 1120px) {
    .article-side { display: block; }
  }
  @media (max-width: 900px) {
    .nav-links a { padding: 6px 9px; font-size: 13px; }
    .prose { padding: 28px 22px 34px; }
    .learn-path { padding: 32px 22px; margin-left: 0; margin-right: 0; }
    .hero { padding: 64px 20px 52px; }
    .card-grid.wide .post-card { flex-direction: column; align-items: stretch; }
    .card-grid.wide .post-card .p-icon { width: 64px; height: 64px; font-size: 30px; }
  }
  @media (max-width: 640px) {
    .nav-links { display: none; }
    .article-layout { padding-top: 26px; }
    .article-hero h1 { font-size: 24px; }
    .s-head .s-tag { margin-left: 0; }
    .hero-stats { gap: 26px; }
    .learn-path { margin-bottom: 56px; }
  }

  /* 备案号：徽标 + 文字（全站适用） */
  .f-icp { display: flex; justify-content: center; align-items: center; }
  .f-icp a {
    display: inline-flex; align-items: center; gap: 6px;
    color: var(--muted); transition: color 0.2s;
  }
  .f-icp a:hover { color: var(--cyan); }
  .f-icp svg { flex: 0 0 auto; }