:root {
    --ink: #12151c;
    --muted: #5b6472;
    --faint: #8891a0;
    --surface: #ffffff;
    --surface-alt: #f6f8fb;
    --border: #e6eaf0;
    --blue: #1d8bdd;
    --purple: #6d61b1;
    --gradient: linear-gradient(135deg, #1d8bdd, #6d61b1);
    --danger: #e2574c;
    --danger-bg: #fdeceb;
    --success: #1a9c72;
    --success-bg: #e9f7f1;
    --radius: 14px;
  }

  * {
    box-sizing: border-box;
  }

  html {
    scroll-behavior: smooth;
  }

  body {
    margin: 0;
    background: var(--surface-alt);
    color: var(--ink);
    font-family: 'Inter',"Inter Fallback", sans-serif;
    line-height: 1.65;
  }

  .mono {
    font-family: 'IBM Plex Mono', monospace;
  }

  .display {
    font-family: 'Space Grotesk', sans-serif;
  }

  a {
    color: var(--blue);
    text-decoration: none;
  }

  a:hover {
    text-decoration: underline;
  }

  /* top bar */
  .topbar {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .wordmark {
    font-family: 'IBM Plex Mono', monospace;
    font-weight: 600;
    font-size: 18px;
    color: var(--ink);
  }

  .wordmark span {
    color: var(--blue);
  }

  .crumb {
    font-size: 13px;
    color: var(--faint);
  }

  .crumb a {
    color: var(--faint);
  }

  /* hero */
  .hero {
    position: relative;
    overflow: hidden;
    background: var(--ink);
    padding: 64px 24px 88px;
  }

  .hero::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image: radial-gradient(rgba(255, 255, 255, .14) 1px, transparent 1px);
    background-size: 22px 22px;
    mask-image: linear-gradient(180deg, rgba(0, 0, 0, .9), transparent 85%);
  }

  .hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background: var(--gradient);
    opacity: .22;
    mix-blend-mode: screen;
  }

  .hero-inner {
    position: relative;
    max-width: 1350px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1.3fr .7fr;
    gap: 40px;
    align-items: center;
  }

  .eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 14px;
    border-radius: 999px;
    background: rgba(255, 255, 255, .08);
    border: 1px solid rgba(255, 255, 255, .16);
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    letter-spacing: .02em;
    color: #cfe0f7;
    margin-bottom: 20px;
  }

  .eyebrow .dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--danger);
  }

  h1.title {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 700;
    font-size: clamp(28px, 4vw, 42px);
    line-height: 1.15;
    color: #fff;
    margin: 0 0 18px;
  }

  .hero-sub {
    color: #c3ccdc;
    font-size: 16px;
    max-width: 52ch;
    margin: 0 0 26px;
  }

  .meta-row {
    display: flex;
    align-items: center;
    gap: 14px;
    flex-wrap: wrap;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12.5px;
    color: #9aa6ba;
  }

  .meta-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
  }

  .meta-item svg {
    flex-shrink: 0;
  }

  .meta-item a {
    color: #9aa6ba;
    text-decoration: none;
    transition: color 0.2s ease;
  }

  .meta-item a:hover {
    color: #fff;
    text-decoration: underline;
  }

  .meta-row i.sep {
    color: #6d61b1;
    font-style: normal;
  }

  /* signature lock */
  .lock-wrap {
    display: flex;
    justify-content: center;
  }

  .lock-card {
    background: rgba(255, 255, 255, .05);
    border: 1px solid rgba(255, 255, 255, .14);
    border-radius: 20px;
    padding: 24px;
    text-align: center;
    backdrop-filter: blur(2px);
  }

  .lock-state {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    letter-spacing: .06em;
    text-transform: uppercase;
    margin-top: 14px;
    transition: color .5s ease;
    color: var(--danger);
  }

  .lock-state.secure {
    color: var(--success);
  }

  #shackle {
    transform-origin: 100px 78px;
    transition: transform .7s cubic-bezier(.2, .9, .25, 1);
  }

  #warnbadge {
    transition: opacity .4s ease;
  }

  #lockbody {
    transition: fill .5s ease;
  }

  .lock-card.secure #shackle {
    transform: rotate(0deg) translateY(0);
  }

  .lock-card:not(.secure) #shackle {
    transform: rotate(-14deg) translateY(-4px);
  }

  .lock-card.secure #warnbadge {
    opacity: 0;
  }

  .lock-card.secure #lockbody {
    fill: #1a9c72;
  }

  .lock-card:not(.secure) #lockbody {
    fill: #e2574c;
  }

  /* layout */
  .layout {
    max-width: 1350px;
    margin: -48px auto 0;
    padding: 0 24px 80px;
    position: relative;
    display: grid;
    grid-template-columns: 320px 1fr;
    gap: 40px;
  }

  .toc {
    position: sticky;
    top: 80px;
    align-self: start;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 18px;
  }

  .toc-label {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    letter-spacing: .06em;
    text-transform: uppercase;
    color: var(--faint);
    margin: 0 0 12px;
  }

  .toc ol {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 9px;
  }

  .toc a {
    font-size: 13.5px;
    color: var(--muted);
  }

  .toc a:hover {
    color: var(--blue);
    text-decoration: none;
  }

  .article {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 40px 44px;
  }

  .article p {
    color: #333a45;
    font-size: 15.5px;
  }

  h2.section {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: 22px;
    margin: 40px 0 14px;
    scroll-margin-top: 24px;
  }

  h2.section:first-of-type {
    margin-top: 0;
  }

  h3.sub {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: 17px;
    margin: 26px 0 10px;
  }

  /* reason cards */
  .reason-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 14px;
    margin: 20px 0;
  }

  .reason-card {
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px 18px;
    background: var(--surface-alt);
  }

  .reason-card .tag {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    color: var(--purple);
    text-transform: uppercase;
    letter-spacing: .04em;
  }

  .reason-card h4 {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 15px;
    margin: 6px 0 6px;
  }

  .reason-card p {
    font-size: 13.5px;
    color: var(--muted);
    margin: 0;
  }

  /* callout */
  .callout {
    border-radius: 14px;
    padding: 22px 24px;
    margin: 26px 0;
    background: linear-gradient(135deg, #eef4fc, #f1eef8);
    border: 1px solid #dfe6f5;
  }

  .callout .tag {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    color: var(--blue);
    text-transform: uppercase;
    letter-spacing: .04em;
  }

  .callout h4 {
    font-family: 'Space Grotesk', sans-serif;
    font-size: 16px;
    margin: 8px 0 8px;
  }

  .callout p {
    margin: 0;
    font-size: 14.5px;
    color: #3a4150;
  }

  /* steps */
  ol.steps {
    counter-reset: step;
    list-style: none;
    margin: 18px 0;
    padding: 0;
  }

  ol.steps li {
    counter-increment: step;
    position: relative;
    padding: 0 0 20px 44px;
    border-left: 2px solid var(--border);
    margin-left: 14px;
  }

  ol.steps li:last-child {
    border-color: transparent;
    padding-bottom: 0;
  }

  ol.steps li::before {
    content: counter(step);
    position: absolute;
    left: -15px;
    top: 0;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--gradient);
    color: #fff;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12.5px;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
  }

  ol.steps strong {
    display: block;
    font-family: 'Space Grotesk', sans-serif;
    font-size: 15px;
    margin-bottom: 3px;
  }

  ol.steps span {
    font-size: 14px;
    color: var(--muted);
  }

  /* faq */
  .faq-item {
    border: 1px solid var(--border);
    border-radius: 12px;
    margin-bottom: 10px;
    overflow: hidden;
  }

  .faq-q {
    padding: 14px 18px;
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: 14.5px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--surface-alt);
  }

  .faq-q::after {
    content: "+";
    font-family: 'IBM Plex Mono', monospace;
    color: var(--purple);
    font-size: 16px;
    transition: transform .25s ease;
  }

  .faq-item.open .faq-q::after {
    transform: rotate(45deg);
  }

  .faq-a {
    max-height: 0;
    overflow: hidden;
    transition: max-height .3s ease;
  }

  .faq-item.open .faq-a {
    max-height: 200px;
  }

  .faq-a p {
    padding: 0 18px 16px;
    margin: 0;
    font-size: 14px;
    color: var(--muted);
  }

  /* related */
  .related-row {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 14px;
    margin: 18px 0;
  }

  .related-card {
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 16px;
    background: var(--surface-alt);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
  }

  .related-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  }

  .related-card .related-img-link {
    display: block;
    width: 100%;
    height: 140px;
    border-radius: 8px;
    overflow: hidden;
    margin-bottom: 12px;
  }

  .related-card .related-img-link img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    transition: transform 0.3s ease;
  }

  .related-card:hover .related-img-link img {
    transform: scale(1.05);
  }

  .related-card .tag {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 10.5px;
    color: var(--faint);
    text-transform: uppercase;
  }

  .related-card a.related-title {
    display: block;
    font-family: 'Space Grotesk', sans-serif;
    font-size: 14px;
    color: var(--ink);
    margin-top: 6px;
    font-weight: 600;
    line-height: 1.35;
  }

  .related-card a.related-title:hover {
    color: var(--blue);
  }

  /* cta */
  .cta {
    margin-top: 36px;
    border-radius: 16px;
    padding: 32px;
    background: var(--ink);
    position: relative;
    overflow: hidden;
  }

  .cta::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image: radial-gradient(rgba(255, 255, 255, .1) 1px, transparent 1px);
    background-size: 20px 20px;
  }

  .cta::after {
    content: "";
    position: absolute;
    inset: 0;
    background: var(--gradient);
    opacity: .25;
  }

  .cta-inner {
    position: relative;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap;
  }

  .cta h3 {
    font-family: 'Space Grotesk', sans-serif;
    color: #fff;
    font-size: 19px;
    margin: 0 0 4px;
  }

  .cta p {
    color: #c3ccdc;
    font-size: 14px;
    margin: 0;
  }

  .cta-btn {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 13px;
    font-weight: 600;
    background: #fff;
    color: var(--ink);
    padding: 11px 20px;
    border-radius: 999px;
    white-space: nowrap;
  }

  .cta-btn:hover {
    text-decoration: none;
    background: #e8ecf3;
  }

  footer {
    max-width: 1080px;
    margin: 0 auto;
    padding: 0 24px 60px;
    text-align: center;
    color: var(--faint);
    font-size: 12.5px;
  }

  @media (max-width:820px) {
    .hero-inner {
      grid-template-columns: 1fr;
    }

    .lock-wrap {
      order: -1;
    }

    .layout {
      grid-template-columns: 1fr;
      margin-top: -32px;
    }

    .toc {
      position: static;
    }

    .article {
      padding: 28px 22px;
    }

    .reason-grid,
    .related-row {
      grid-template-columns: 1fr;
    }

    .cta-inner {
      flex-direction: column;
      align-items: flex-start;
    }
  }

  .article h2 {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: 22px;
    margin: 40px 0 14px;
    scroll-margin-top: 24px;
  }

  .article h2:first-of-type {
    margin-top: 0;
  }

  .article h3 {
    font-family: 'Space Grotesk', sans-serif;
    font-weight: 600;
    font-size: 17px;
    margin: 26px 0 10px;
  }

  .article ul,
  .article ol {
    color: #333a45;
    font-size: 15.5px;
    margin: 18px 0;
    padding-left: 24px;
  }

  .article>img {
    max-width: 100%;
    height: auto;
    border-radius: 12px;
    margin: 16px 0;
  }

  .article blockquote {
    border-left: 4px solid var(--blue);
    margin: 20px 0;
    padding: 12px 20px;
    background: var(--surface-alt);
    border-radius: 0 10px 10px 0;
    font-style: italic;
  }

  .article pre,
  .article code {
    font-family: 'IBM Plex Mono', monospace;
    background: var(--surface-alt);
    border-radius: 6px;
  }

  .article pre {
    padding: 16px;
    overflow-x: auto;
    border: 1px solid var(--border);
  }

  .article-tags a:hover {
    background: var(--blue) !important;
    color: #fff !important;
    border-color: var(--blue) !important;
  }