:root {
      --paper: #eef3f6; --sheet: #ffffff; --ink: #16222e; --ink-soft: #52616f; --ink-faint: #93a1ad;
      --grid: rgba(29, 95, 191, 0.07); --line: #d5dee6; --line-blue: #b9cde8;
      --blue: #1d5fbf; --blue-deep: #123d7d; --blue-wash: #e8f0fb;
      --orange: #e8641f; --orange-wash: #fdeadd; --green: #218a5b; --green-wash: #e6f3ec; --red: #d64545;
      --font-body: "Noto Sans SC", sans-serif; --font-mono: "JetBrains Mono", monospace;
    }
    * { margin: 0; padding: 0; box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body { background: var(--paper); color: var(--ink); font-family: var(--font-body); font-size: 16px; line-height: 1.8; overflow-x: hidden; }
    body::before {
      content: ""; position: fixed; inset: 0;
      background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px);
      background-size: 28px 28px; pointer-events: none; z-index: 0;
    }
    ::selection { background: var(--blue); color: #fff; }
    a { color: inherit; text-decoration: none; }
    ul, ol { list-style: none; }

    .wrap { max-width: 1220px; margin: 0 auto; padding: 0 28px; position: relative; z-index: 1; }
    .wrap--article { max-width: 760px; }

    .topbar { position: sticky; top: 0; z-index: 50; background: rgba(255, 255, 255, 0.92); backdrop-filter: blur(10px); border-bottom: 1px solid var(--line-blue); }
    .topbar__inner { display: flex; align-items: center; gap: 26px; height: 62px; }
    .brand { display: flex; align-items: center; gap: 11px; font-weight: 900; font-size: 20px; letter-spacing: 0.04em; }
    .brand__mark { width: 36px; height: 36px; border: 1.5px dashed var(--blue); border-radius: 8px; display: grid; place-items: center; background: var(--blue-wash); overflow: hidden; }
    .brand__mark img { width: 27px; height: 27px; object-fit: contain; display: block; }
    .brand__sheet { font-family: var(--font-mono); font-size: 10px; color: var(--blue); border: 1px solid var(--line-blue); background: var(--blue-wash); padding: 2px 8px; border-radius: 3px; letter-spacing: 0.14em; }
    .main-nav { display: flex; align-items: center; gap: 2px; margin-left: 8px; }
    .main-nav a { font-size: 14px; padding: 6px 16px; color: var(--ink-soft); border-radius: 4px; transition: color 0.2s, background 0.2s; font-weight: 500; }
    .main-nav a .no { font-family: var(--font-mono); font-size: 10px; color: var(--ink-faint); margin-right: 6px; }
    .main-nav a:hover { color: var(--blue); background: var(--blue-wash); }
    .main-nav a.is-active { color: var(--blue); font-weight: 700; }
    .main-nav a.is-active .no { color: var(--orange); }
    .topbar__right { margin-left: auto; display: flex; align-items: center; gap: 12px; }
    .lang-switch { position: relative; }
    .lang-switch__btn { display: flex; align-items: center; gap: 7px; background: transparent; border: 1px solid var(--line); color: var(--ink-soft); font-size: 12.5px; font-family: var(--font-mono); cursor: pointer; padding: 7px 13px; border-radius: 4px; transition: border-color 0.2s, color 0.2s; }
    .lang-switch__btn:hover { border-color: var(--blue); color: var(--blue); }
    .lang-switch__menu { position: absolute; top: calc(100% + 8px); right: 0; min-width: 142px; background: var(--sheet); border: 1px solid var(--line-blue); border-radius: 6px; box-shadow: 0 12px 28px rgba(18, 61, 125, 0.14); padding: 6px; display: none; z-index: 60; }
    .lang-switch__menu.is-open { display: block; }
    .lang-switch__menu li { border-radius: 4px; overflow: hidden; }
    .lang-switch__menu li > a, .lang-switch__menu li.is-current { padding: 8px 12px; font-size: 13px; color: var(--ink-soft); cursor: pointer; border-radius: 4px; display: flex; justify-content: space-between; align-items: center; text-decoration: none; }
    .lang-switch__menu li > a:hover { background: var(--blue-wash); color: var(--ink); }
    .lang-switch__menu li.is-current { color: var(--blue); font-weight: 700; }
    .lang-switch__menu li.is-current::after { content: "✓"; font-size: 11px; }
    .nav-burger { display: none; background: var(--sheet); border: 1px solid var(--line); color: var(--ink); width: 38px; height: 38px; border-radius: 6px; font-size: 15px; cursor: pointer; }

    .art-hero { padding: 46px 0 0; }
    .breadcrumb { font-family: var(--font-mono); font-size: 12px; color: var(--ink-faint); margin-bottom: 18px; display: flex; gap: 8px; align-items: center; }
    .breadcrumb a { color: var(--blue); }
    .art-meta { display: flex; align-items: center; gap: 14px; font-family: var(--font-mono); font-size: 11.5px; color: var(--ink-faint); margin-bottom: 16px; flex-wrap: wrap; }
    .art-meta .tag { color: var(--blue); background: var(--blue-wash); border: 1px solid var(--line-blue); border-radius: 4px; padding: 2px 9px; }
    .art-hero h1 { font-weight: 900; font-size: clamp(28px, 4vw, 42px); line-height: 1.4; }
    .art-lead { margin-top: 16px; font-size: 16px; color: var(--ink-soft); border-left: 3px solid var(--blue); padding-left: 18px; }

    .art-body { padding: 40px 0 90px; }
    .art-body h2 { font-size: 22px; font-weight: 900; margin: 44px 0 14px; padding-top: 8px; border-top: 1px solid var(--line); }
    .art-body h2:first-child { border-top: none; margin-top: 0; }
    .art-body h3 { font-size: 17px; font-weight: 700; margin: 26px 0 10px; color: var(--blue-deep); }
    .art-body p { font-size: 15.5px; color: var(--ink-soft); margin-bottom: 14px; }
    .art-body p strong { color: var(--ink); }
    .art-body ul, .art-body ol { margin: 0 0 16px; padding-left: 4px; }
    .art-body ul li, .art-body ol li { font-size: 15px; color: var(--ink-soft); margin-bottom: 8px; padding-left: 22px; position: relative; }
    .art-body ul li::before { content: "▸"; color: var(--blue); position: absolute; left: 0; }
    .art-body code { font-family: var(--font-mono); font-size: 13px; background: var(--blue-wash); color: var(--blue-deep); padding: 2px 7px; border-radius: 4px; }
    .code-card {
      background: var(--blue-deep); color: #d9e6f7; font-family: var(--font-mono); font-size: 13px; line-height: 1.9;
      padding: 22px 24px; border-radius: 8px; box-shadow: 0 18px 40px rgba(18, 61, 125, 0.24);
      overflow-x: auto; white-space: pre; margin: 18px 0 22px;
    }
    .code-card .cm { color: #6d89ad; }
    .code-card .kw { color: #ffc38a; }
    .code-card .st { color: #8fc1ff; }
    .code-card .nu { color: #a4e3b6; }
    .callout {
      border: 1px solid var(--line-blue); background: var(--blue-wash); border-left: 3px solid var(--blue);
      padding: 16px 20px; font-size: 14px; color: var(--ink-soft); margin: 18px 0 22px; border-radius: 0 4px 4px 0;
    }
    .callout b { color: var(--ink); }

    .cmp-table { width: 100%; border-collapse: collapse; margin: 18px 0 26px; font-size: 13.5px; background: var(--sheet); border: 1px solid var(--line-blue); }
    .cmp-table th, .cmp-table td { padding: 12px 14px; border-bottom: 1px solid var(--line); text-align: left; }
    .cmp-table th { background: var(--blue-wash); font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.08em; color: var(--blue-deep); }
    .cmp-table td:first-child, .cmp-table th:first-child { font-weight: 700; color: var(--ink); }
    .cmp-table tr:last-child td { border-bottom: none; }
    .table-hint { display: none; }

    .art-foot { border-top: 1.5px solid var(--blue); padding-top: 28px; margin-top: 50px; display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 16px; }
    .art-foot a.back { display: inline-flex; align-items: center; gap: 8px; font-weight: 700; color: var(--blue); font-size: 14px; }
    .art-foot .share { font-family: var(--font-mono); font-size: 11.5px; color: var(--ink-faint); }

    /* ============ Buttons ============ */
    .btn {
      display: inline-flex; align-items: center; gap: 10px; font-size: 15px; font-weight: 700;
      padding: 13px 26px; border-radius: 6px; cursor: pointer; border: 1.5px solid transparent;
      transition: transform 0.18s, box-shadow 0.18s, background 0.18s, color 0.18s; white-space: nowrap;
    }
    .btn--primary { background: var(--blue); color: #fff; box-shadow: 0 10px 24px rgba(29, 95, 191, 0.3); }
    .btn--primary:hover { transform: translateY(-3px); box-shadow: 0 16px 30px rgba(29, 95, 191, 0.38); background: var(--blue-deep); }

    /* ============ In-article download CTA ============ */
    .art-cta {
      border: 1.5px dashed var(--blue);
      background: var(--blue-wash);
      padding: 30px 32px;
      margin: 48px 0 6px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 22px;
      flex-wrap: wrap;
    }
    .art-cta h3 { font-weight: 900; font-size: 19px; margin-bottom: 6px; }
    .art-cta p { font-size: 13.5px; color: var(--ink-soft); max-width: 420px; margin: 0; }

    /* ============ Floating download widget ============ */
    .float-dl {
      position: fixed; right: 22px; bottom: 22px; z-index: 80;
      background: var(--sheet); border: 1.5px solid var(--blue); border-radius: 10px;
      box-shadow: 0 16px 40px rgba(18, 61, 125, 0.24); padding: 12px 16px 12px 12px;
      max-width: 250px; opacity: 0; transform: translateY(16px); pointer-events: none;
      transition: opacity 0.3s, transform 0.3s;
    }
    .float-dl.is-visible { opacity: 1; transform: none; pointer-events: auto; }
    .float-dl__link { display: flex; align-items: center; gap: 12px; color: inherit; }
    .float-dl__icon {
      width: 40px; height: 40px; border-radius: 8px; background: var(--blue-wash);
      display: grid; place-items: center; color: var(--blue); font-size: 17px; flex-shrink: 0;
    }
    .float-dl__text b { display: block; font-size: 13.5px; font-weight: 900; color: var(--ink); }
    .float-dl__text span { font-size: 11.5px; color: var(--ink-soft); }
    .float-dl__close {
      position: absolute; top: -8px; right: -8px; width: 20px; height: 20px; border-radius: 50%;
      background: var(--ink); color: #fff; font-size: 9px; border: none; cursor: pointer;
      display: grid; place-items: center;
    }

    .site-foot { border-top: 1.5px solid var(--blue); background: var(--sheet); padding: 62px 0 0; position: relative; z-index: 1; }
    .foot-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1.1fr; gap: 44px; padding-bottom: 50px; }
    .foot-brand p { color: var(--ink-soft); font-size: 13.5px; margin-top: 16px; max-width: 300px; }
    .foot-col h4 { font-family: var(--font-mono); font-size: 10.5px; letter-spacing: 0.26em; color: var(--blue); margin-bottom: 18px; font-weight: 400; display: flex; align-items: center; gap: 10px; }
    .foot-col h4::after { content: ""; flex: 1; height: 1px; background: var(--line); }
    .foot-col ul li { margin-bottom: 11px; }
    .foot-col ul a { font-size: 14px; color: var(--ink-soft); transition: color 0.2s, padding-left 0.2s; }
    .foot-col ul a:hover { color: var(--blue); padding-left: 6px; }
    .foot-col ul a i { font-size: 11px; margin-right: 8px; color: var(--ink-faint); }
    .foot-langs { display: flex; flex-wrap: wrap; gap: 8px; }
    .foot-langs span { font-family: var(--font-mono); font-size: 11.5px; border: 1px solid var(--line); border-radius: 4px; padding: 5px 13px; color: var(--ink-soft); cursor: pointer; transition: all 0.2s; background: var(--paper); }
    .foot-langs span:hover, .foot-langs span.on { color: #fff; background: var(--blue); border-color: var(--blue); }
    .foot-word { font-weight: 900; font-size: clamp(70px, 12.5vw, 172px); line-height: 1; text-align: center; color: transparent; -webkit-text-stroke: 1px var(--line-blue); user-select: none; letter-spacing: 0.08em; transform: translateY(8px); }
    .foot-base { border-top: 1px solid var(--line); padding: 20px 0; display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; font-family: var(--font-mono); font-size: 11.5px; color: var(--ink-faint); }
    .foot-base a { color: var(--ink-soft); }
    .foot-base a:hover { color: var(--blue); }

    @media (max-width: 720px) {
      .wrap { padding: 0 18px; }
      .brand__sheet { display: none; }
      .main-nav { display: none; position: absolute; top: 62px; left: 0; right: 0; flex-direction: column; align-items: stretch; background: var(--sheet); border-bottom: 1.5px solid var(--blue); padding: 10px 20px 18px; margin-left: 0; }
      .main-nav.is-open { display: flex; }
      .main-nav a { padding: 12px 8px; font-size: 16px; }
      .nav-burger { display: block; }
      .cmp-table { display: block; overflow-x: auto; white-space: nowrap; }
      .table-hint { display: block; text-align: center; font-size: 12px; color: var(--ink-faint); margin: -14px 0 20px; }
      .foot-grid { grid-template-columns: 1fr; gap: 32px; }
      .foot-base { justify-content: center; text-align: center; }
      .float-dl { right: 14px; bottom: 14px; max-width: 210px; padding: 10px 14px 10px 10px; }
      .art-cta { padding: 26px 22px; }
    }
    @media (prefers-reduced-motion: reduce) {
      *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
      html { scroll-behavior: auto; }
    }