@charset "UTF-8";
      /* ==================================================================
         Design tokens. Every colour is annotated with its measured WCAG
         contrast ratio against the surface it is used on. Target: 2.2 AAA
         (7:1 body text). Editorial system: serif display over sans body,
         hairline rules, generous measure.
         ================================================================== */
      :root {
        --type-display: "Iowan Old Style", "Palatino Nova", Palatino, "New York", ui-serif, Georgia, serif;
        --type-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
        --type-mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;

        --bg-page: #ffffff;
        --bg-alt: #f7f5f1;      /* warm paper for alternating bands */
        --bg-card: #fdfcfa;
        --ink: #1d1d1f;         /* 16.7:1 on #fff — AAA */
        --ink-soft: #3a3a3c;    /* 11.3:1 on #fff — AAA */
        --ink-mute: #4d4d55;    /*  8.4:1 on #fff, 7.8:1 on --bg-alt — AAA */
        --rule: #e4e1da;
        --rule-strong: #c9c5bb;

        --link: #004caf;        /*  7.9:1 on #fff, 7.4:1 on --bg-alt — AAA */
        --link-hover: #003a86;
        --eyebrow: #684d00;     /*  8.0:1 on #fff — AAA */
        --btn-bg: #1d1d1f;      /* white text on it: 16.7:1 — AAA */
        --btn-text: #ffffff;
        --focus-ring: #004caf;

        --ok: #14532d;          /*  9.7:1 on #fff — AAA */
        --bad: #7f1d1d;         /*  9.9:1 on #fff — AAA */

        --code-bg: #14161c;
        --code-text: #f2f3f5;   /* 15.9:1 on #14161c — AAA */

        --shadow-sm: 0 1px 2px rgb(29 29 31 / 0.06);
        --shadow-md: 0 12px 32px -12px rgb(29 29 31 / 0.18);
        --radius-sm: 8px;
        --radius-md: 14px;
        --radius-pill: 999px;
        --measure: 68ch;
      }

      [data-theme="dark"] {
        --bg-page: #0b0e14;
        --bg-alt: #10141c;
        --bg-card: #171b24;
        --ink: #f5f5f7;         /* 17.0:1 on #0b0e14 — AAA */
        --ink-soft: #d6d9e0;    /* 13.1:1 — AAA */
        --ink-mute: #b3bac7;    /*  9.2:1 on page, 8.6:1 on card — AAA */
        --rule: #262c38;
        --rule-strong: #3a4252;

        --link: #8cc0ff;        /*  9.5:1 on page, 8.9:1 on card — AAA */
        --link-hover: #b8d8ff;
        --eyebrow: #e3c878;     /* 10.5:1 on page — AAA */
        --btn-bg: #f5f5f7;
        --btn-text: #16181d;    /* 15.9:1 on #f5f5f7 — AAA */
        --focus-ring: #8cc0ff;

        --ok: #86efac;          /* 13.6:1 on page — AAA */
        --bad: #fca5a5;         /* 10.3:1 on page — AAA */

        --code-bg: #05070b;
        --code-text: #eef0f4;

        --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.6);
        --shadow-md: 0 12px 32px -12px rgb(0 0 0 / 0.7);
      }

      /* OS dark preference when no explicit choice is stored. */
      @media (prefers-color-scheme: dark) {
        html:not([data-theme="light"]) {
          --bg-page: #0b0e14;
          --bg-alt: #10141c;
          --bg-card: #171b24;
          --ink: #f5f5f7;
          --ink-soft: #d6d9e0;
          --ink-mute: #b3bac7;
          --rule: #262c38;
          --rule-strong: #3a4252;
          --link: #8cc0ff;
          --link-hover: #b8d8ff;
          --eyebrow: #e3c878;
          --btn-bg: #f5f5f7;
          --btn-text: #16181d;
          --focus-ring: #8cc0ff;
          --ok: #86efac;
          --bad: #fca5a5;
          --code-bg: #05070b;
          --code-text: #eef0f4;
          --shadow-sm: 0 1px 2px rgb(0 0 0 / 0.6);
          --shadow-md: 0 12px 32px -12px rgb(0 0 0 / 0.7);
        }
      }

      @view-transition { navigation: auto; }

      *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

      html {
        font-family: var(--type-body);
        font-size: 16px;
        line-height: 1.65;
        color: var(--ink);
        background-color: var(--bg-page);
        scroll-behavior: smooth;
        -webkit-text-size-adjust: 100%;
        text-rendering: optimizeLegibility;
      }

      body { min-height: 100vh; display: flex; flex-direction: column; }

      ::selection { background: var(--link); color: var(--bg-page); }

      :focus-visible {
        outline: 3px solid var(--focus-ring);
        outline-offset: 3px;
        border-radius: 2px;
      }

      @media (prefers-reduced-motion: reduce) {
        html { scroll-behavior: auto; }
        *, *::before, *::after {
          animation-duration: 0.01ms !important;
          animation-iteration-count: 1 !important;
          transition-duration: 0.01ms !important;
        }
      }

      @media (prefers-contrast: more) {
        :root, [data-theme="dark"] {
          --ink-soft: var(--ink);
          --ink-mute: var(--ink);
          --rule: var(--rule-strong);
        }
      }

      /* Reading progress — scroll-driven, zero JS, aria-hidden. */
      .progress {
        position: fixed;
        top: 0; left: 0;
        height: 3px; width: 100%;
        background: var(--link);
        transform-origin: 0 50%;
        transform: scaleX(0);
        z-index: 2000;
      }
      @supports (animation-timeline: scroll()) {
        .progress { animation: grow linear both; animation-timeline: scroll(root); }
        @keyframes grow { from { transform: scaleX(0); } to { transform: scaleX(1); } }
      }

      .skip-link {
        position: absolute;
        top: -120px; left: 1rem;
        background: var(--btn-bg); color: var(--btn-text);
        padding: 0.8rem 1.6rem;
        z-index: 10000;
        border-radius: var(--radius-pill);
        font-weight: 600;
        transition: top 0.2s ease;
      }
      .skip-link:focus { top: 1rem; }
      .visually-hidden {
        position: absolute; width: 1px; height: 1px;
        overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap;
      }

      .wrap { width: 100%; max-width: 1180px; margin: 0 auto; padding: 0 1.75rem; }

      /* ==== Navigation ==== */
      .navbar {
        position: sticky; top: 0; z-index: 1000;
        background: color-mix(in srgb, var(--bg-page) 88%, transparent);
        backdrop-filter: blur(14px);
        -webkit-backdrop-filter: blur(14px);
        border-bottom: 1px solid var(--rule);
      }
      .nav-inner {
        display: flex; align-items: center; justify-content: space-between;
        gap: 1rem; min-height: 64px; flex-wrap: wrap;
      }
      .brand {
        display: inline-flex; align-items: center; gap: 0.6rem;
        font-family: var(--type-display);
        font-size: 1.3rem; font-weight: 700; letter-spacing: -0.01em;
        color: var(--ink); text-decoration: none; min-height: 44px;
      }
      .brand img { height: 30px; width: 30px; }
      .nav-toggle-input { position: absolute; opacity: 0; }
      .nav-toggle-label {
        display: none;
        min-width: 44px; min-height: 44px;
        align-items: center; justify-content: center;
        border: 1px solid var(--rule-strong); border-radius: var(--radius-sm);
        cursor: pointer; font-size: 1.25rem; color: var(--ink);
      }
      .nav-links { display: flex; align-items: center; gap: 0.1rem; list-style: none; flex-wrap: wrap; }
      .nav-links a {
        display: inline-flex; align-items: center;
        min-height: 44px; padding: 0 0.7rem;
        color: var(--ink-soft);
        font-weight: 500; font-size: 0.88rem; letter-spacing: 0.01em;
        text-decoration: none; border-radius: var(--radius-sm);
      }
      .nav-links a:hover { color: var(--ink); background: var(--bg-alt); }
      .nav-links a[aria-current="page"] {
        color: var(--ink); font-weight: 700;
        text-decoration: underline; text-underline-offset: 8px;
        text-decoration-color: var(--link); text-decoration-thickness: 2px;
      }
      .nav-right { display: flex; align-items: center; gap: 0.6rem; }
      .nav-cta {
        display: inline-flex; align-items: center;
        min-height: 40px; padding: 0 1.1rem;
        background: var(--btn-bg); color: var(--btn-text);
        border-radius: var(--radius-pill);
        font-size: 0.88rem; font-weight: 600; text-decoration: none;
        white-space: nowrap;
      }
      .nav-cta:hover { opacity: 0.85; }
      .theme-btn {
        background: transparent;
        border: 1px solid var(--rule-strong);
        color: var(--ink);
        min-height: 40px; min-width: 44px;
        padding: 0 0.8rem;
        border-radius: var(--radius-pill);
        cursor: pointer; font-size: 0.85rem; font-weight: 600;
        font-family: inherit;
      }
      .theme-btn:hover { background: var(--bg-alt); }

      @media (max-width: 1120px) {
        .nav-toggle-label { display: inline-flex; }
        .nav-links {
          display: none; flex-direction: column; align-items: stretch;
          width: 100%; padding: 0.5rem 0 1rem;
          border-top: 1px solid var(--rule); margin-top: 0.25rem;
        }
        .nav-toggle-input:checked ~ .nav-links { display: flex; }
        .nav-toggle-input:focus-visible ~ .nav-toggle-label {
          outline: 3px solid var(--focus-ring); outline-offset: 3px;
        }
        .nav-cta { display: none; }
      }

      /* ==== Page header ==== */
      .page-header { padding: 4.5rem 0 2.75rem; border-bottom: 1px solid var(--rule); }
      .breadcrumb { font-size: 0.85rem; color: var(--ink-mute); margin-bottom: 2rem; }
      .breadcrumb ol { list-style: none; display: flex; flex-wrap: wrap; gap: 0.5rem; }
      .breadcrumb li + li::before { content: "\203A"; margin-right: 0.5rem; color: var(--ink-mute); }
      .breadcrumb a { color: var(--link); text-decoration: none; }
      .breadcrumb a:hover { text-decoration: underline; }
      .eyebrow {
        font-size: 0.8rem; font-weight: 700;
        letter-spacing: 0.14em; text-transform: uppercase;
        color: var(--eyebrow);
        margin-bottom: 1.1rem;
      }
      .page-title {
        font-family: var(--type-display);
        font-size: clamp(2.3rem, 4.5vw, 3.4rem);
        font-weight: 700;
        letter-spacing: -0.015em;
        line-height: 1.12;
        max-width: 26ch;
        margin-bottom: 1.25rem;
        overflow-wrap: break-word;
        text-wrap: balance;
      }
      .deck {
        font-size: 1.25rem;
        line-height: 1.55;
        color: var(--ink-soft);
        max-width: 58ch;
      }
      .article-meta {
        display: flex; flex-wrap: wrap; gap: 0.5rem 1.25rem;
        margin-top: 1.75rem;
        font-size: 0.85rem; color: var(--ink-mute);
      }

      /* ==== Article body ==== */
      .content-shell { padding: 3rem 0 2rem; }
      .content-body { font-size: 1.06rem; line-height: 1.75; max-width: var(--measure); }
      .content-body h2 {
        font-family: var(--type-display);
        font-size: 1.7rem; font-weight: 700; letter-spacing: -0.01em;
        line-height: 1.25;
        margin: 2.75rem 0 1rem;
        overflow-wrap: break-word;
      }
      .content-body h3 {
        font-size: 1.15rem; font-weight: 700;
        margin: 2rem 0 0.75rem;
      }
      .content-body h2:first-child { margin-top: 0; }
      .content-body p { margin-bottom: 1.4rem; color: var(--ink-soft); }
      .content-body ul, .content-body ol { margin: 0 0 1.4rem 1.6rem; color: var(--ink-soft); }
      .content-body li { margin-bottom: 0.55rem; }
      .content-body li::marker { color: var(--ink-mute); }
      .content-body a { color: var(--link); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 1px; }
      .content-body a:hover { color: var(--link-hover); text-decoration-thickness: 2px; }
      .content-body strong { color: var(--ink); font-weight: 650; }
      .content-body blockquote {
        font-family: var(--type-display);
        font-size: 1.2rem; line-height: 1.55;
        border-left: 3px solid var(--eyebrow);
        padding: 0.35rem 0 0.35rem 1.5rem;
        margin: 2rem 0;
        color: var(--ink);
      }
      .content-body blockquote p { color: var(--ink); margin-bottom: 0.75rem; }
      .content-body blockquote p:last-child { margin-bottom: 0; }
      .content-body code {
        font-family: var(--type-mono);
        font-size: 0.86em;
        background: var(--bg-alt);
        color: var(--ink);
        padding: 0.15rem 0.45rem;
        border-radius: 6px;
        border: 1px solid var(--rule);
        overflow-wrap: break-word;
      }
      .content-body pre {
        background: var(--code-bg);
        color: var(--code-text);
        padding: 1.4rem 1.6rem;
        border-radius: var(--radius-md);
        overflow-x: auto;
        margin: 0 0 1.75rem;
        font-size: 0.92rem;
        line-height: 1.7;
        box-shadow: var(--shadow-sm);
      }
      .content-body pre code { background: transparent; color: inherit; padding: 0; border: none; font-size: 1em; }
      .content-body hr { border: 0; border-top: 1px solid var(--rule); margin: 3rem 0; }

      /* Tables: hairline editorial on wide screens, labelled cards on narrow. */
      .content-body .table-responsive { overflow-x: auto; margin: 2rem 0; }
      .content-body table { width: 100%; border-collapse: collapse; font-size: 0.97rem; }
      .content-body th, .content-body td {
        padding: 0.9rem 1rem;
        border-bottom: 1px solid var(--rule);
        text-align: left; vertical-align: top;
      }
      .content-body thead th {
        font-size: 0.78rem; font-weight: 700;
        letter-spacing: 0.1em; text-transform: uppercase;
        color: var(--ink-mute);
        border-bottom: 2px solid var(--rule-strong);
      }
      .content-body td { color: var(--ink-soft); }
      @media (max-width: 720px) {
        .content-body table, .content-body tbody, .content-body tr, .content-body td { display: block; width: 100%; }
        .content-body thead { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }
        .content-body tr { border: 1px solid var(--rule); border-radius: var(--radius-sm); margin-bottom: 1rem; padding: 0.5rem 0; }
        .content-body td { border-bottom: none; padding: 0.45rem 1rem; }
        .content-body td[data-label]::before {
          content: attr(data-label);
          display: block;
          font-size: 0.72rem; font-weight: 700;
          letter-spacing: 0.1em; text-transform: uppercase;
          color: var(--ink-mute);
          margin-bottom: 0.15rem;
        }
      }

      /* Contents block (injected at build for long pages). */
      .article-toc {
        border: 1px solid var(--rule);
        border-radius: var(--radius-md);
        background: var(--bg-card);
        padding: 1.4rem 1.6rem;
        margin: 0 0 2.5rem;
        max-width: var(--measure);
      }
      .article-toc h2 {
        font-family: var(--type-body);
        font-size: 0.8rem; font-weight: 700;
        letter-spacing: 0.14em; text-transform: uppercase;
        color: var(--ink-mute);
        margin: 0 0 0.75rem;
      }
      .article-toc ol { list-style: decimal-leading-zero; margin: 0 0 0 1.6rem; }
      .article-toc li { margin-bottom: 0.35rem; font-size: 0.95rem; }
      .article-toc li::marker { color: var(--ink-mute); font-size: 0.85em; }
      .article-toc a { color: var(--ink-soft); text-decoration: none; }
      .article-toc a:hover { color: var(--link); text-decoration: underline; }

      .heading-anchor {
        margin-left: 0.4rem;
        color: var(--ink-mute);
        text-decoration: none;
        opacity: 0;
        font-family: var(--type-body);
        font-size: 0.8em;
      }
      h2:hover .heading-anchor, h3:hover .heading-anchor,
      .heading-anchor:focus-visible { opacity: 1; }

      /* Back to top */
      .totop {
        position: fixed; right: 1.4rem; bottom: 1.4rem;
        min-width: 44px; min-height: 44px;
        display: inline-flex; align-items: center; justify-content: center;
        background: var(--btn-bg); color: var(--btn-text);
        border: none; border-radius: var(--radius-pill);
        font-size: 1.1rem; cursor: pointer;
        box-shadow: var(--shadow-md);
        z-index: 900;
      }
      .totop[hidden] { display: none; }

      /* ==== Footer ==== */
      .footer {
        border-top: 1px solid var(--rule);
        background: var(--bg-alt);
        margin-top: 5rem;
        padding: 3.5rem 0 2rem;
        font-size: 0.93rem;
      }
      .footer-brand {
        font-family: var(--type-display);
        font-size: 1.25rem; font-weight: 700;
        margin-bottom: 0.6rem;
      }
      .footer-tagline { color: var(--ink-mute); max-width: 34ch; }
      .footer-grid {
        display: grid;
        grid-template-columns: 1.4fr repeat(3, 1fr);
        gap: 2.5rem;
        padding-bottom: 2.5rem;
      }
      @media (max-width: 860px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
      @media (max-width: 520px) { .footer-grid { grid-template-columns: 1fr; } }
      .footer-heading {
        font-size: 0.76rem; font-weight: 700;
        letter-spacing: 0.14em; text-transform: uppercase;
        color: var(--ink-mute);
        margin-bottom: 0.9rem;
      }
      .footer-links { list-style: none; }
      .footer-links a {
        display: inline-flex; align-items: center;
        min-height: 34px;
        color: var(--ink-soft); text-decoration: none;
      }
      .footer-links a:hover { color: var(--link); text-decoration: underline; }
      .footer-legal {
        border-top: 1px solid var(--rule);
        padding-top: 1.5rem;
        display: flex; align-items: center; justify-content: space-between;
        flex-wrap: wrap; gap: 1rem;
        color: var(--ink-mute); font-size: 0.85rem;
      }
      .footer-legal ul { list-style: none; display: flex; flex-wrap: wrap; gap: 1.25rem; }
      .footer-legal a { color: var(--ink-mute); }
      .footer-legal a:hover { color: var(--link); }

      /* AAA overrides for ssg's injected search widget: its own stylesheet
         ships 6.3-6.9:1 labels; force token colours (>= 7:1 both themes). */
      #ssg-search-btn, #ssg-search-btn span { color: var(--ink-soft) !important; }
      #ssg-search-btn kbd {
        color: var(--ink) !important;
        background: var(--bg-page) !important;
        border-color: var(--rule-strong) !important;
      }