:root {
    color-scheme: dark;
    --paper:#0a0f1c; --surface:#111a2d; --surface-2:#16223a;
    --ink:#e8edf9; --ink-soft:#b9c4da; --muted:#8b9aba;
    --line:#22304b; --line-strong:#2e3f61;
    --brand:#6d94ff; --brand-2:#9db8ff; --brand-ink:#c7d6ff;
  }

  *, *::before, *::after { box-sizing: border-box; }
  html { -webkit-text-size-adjust: 100%; }
  body {
    margin: 0;
    background: var(--paper);
    color: var(--ink);
    font-family: "IBM Plex Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
    font-size: 16px;
    line-height: 1.72;
    -webkit-font-smoothing: antialiased;
  }
  a { color: var(--brand); }
  ::selection { background: var(--brand); color: #fff; }

  .wrap { width: 100%; max-width: 760px; margin-inline: auto; padding-inline: clamp(1.25rem, 5vw, 2rem); }

  header {
    position: sticky; top: 0; z-index: 20;
    background: color-mix(in srgb, var(--paper) 85%, transparent);
    backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--line);
  }
  .nav { display: flex; align-items: center; gap: 1rem; height: 64px; }
  .brand {
    display: inline-flex;
    align-items: center;
    text-decoration: none;
    flex: none;
  }
  .brand-logo { height: 34px; width: auto; display: block; }
  .brand-logo--light { display: none; }
  .brand-logo--dark { display: block; }
  .back {
    margin-left: auto; text-decoration: none; color: var(--muted);
    font-family: "IBM Plex Mono", monospace; font-size: 0.78rem; letter-spacing: 0.04em;
  }
  .back:hover { color: var(--ink); }
  .lang {
    display: inline-flex; border: 1px solid var(--line-strong); border-radius: 999px;
    overflow: hidden; font-family: "IBM Plex Mono", monospace; font-size: 0.72rem; letter-spacing: 0.06em;
  }
  .lang button {
    appearance: none; border: 0; background: transparent; color: var(--muted);
    padding: 0.3rem 0.62rem; cursor: pointer; font: inherit;
    transition: background .2s ease, color .2s ease;
  }
  .lang button[aria-pressed="true"] { background: var(--brand); color: #fff; }

  main { padding-block: clamp(2.5rem, 7vw, 4.5rem) 5rem; }

  .doc-head { margin-bottom: 2.5rem; }
  .doc-head .eyebrow {
    font-family: "IBM Plex Mono", monospace; font-size: 0.72rem; letter-spacing: 0.16em;
    text-transform: uppercase; color: var(--brand); display: block; margin-bottom: 0.9rem;
  }
  h1 {
    font-family: "Bricolage Grotesque", sans-serif; font-weight: 700;
    font-size: clamp(1.8rem, 4.5vw, 2.6rem); line-height: 1.1; letter-spacing: -0.02em;
    margin: 0 0 0.6rem; text-wrap: balance;
  }
  .updated { color: var(--muted); font-size: 0.88rem; font-family: "IBM Plex Mono", monospace; }


  .prose h2 {
    font-family: "Bricolage Grotesque", sans-serif; font-weight: 700;
    font-size: 1.18rem; letter-spacing: -0.01em; line-height: 1.25;
    margin: 2.6rem 0 0.7rem; padding-top: 1.4rem; border-top: 1px solid var(--line);
    scroll-margin-top: 84px;
  }
  .prose h2:first-of-type { border-top: 0; padding-top: 0; margin-top: 0; }
  .prose p { margin: 0 0 1rem; }
  .prose ul { margin: 0 0 1rem; padding-left: 1.2rem; }
  .prose li { margin-bottom: 0.4rem; }
  .prose strong { color: var(--ink); font-weight: 600; }
  .prose .ph { color: var(--brand); font-family: "IBM Plex Mono", monospace; font-size: 0.92em; }

  .contact-card {
    margin: 1rem 0 0; padding: 1.1rem 1.25rem;
    border: 1px solid var(--line); border-radius: 10px; background: var(--surface);
    font-size: 0.94rem;
  }
  .contact-card div { display: flex; gap: 0.6rem; flex-wrap: wrap; }
  .contact-card span { color: var(--muted); min-width: 92px; display: inline-block; }

  footer {
    border-top: 1px solid var(--line); padding-block: 2rem 2.5rem;
    color: var(--muted); font-size: 0.82rem;
  }
  footer a { color: var(--muted); text-decoration: none; }
  footer a:hover { color: var(--ink); }

  [data-lang-block] { display: none; }
  [data-lang-block].active { display: block; }

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