.ak-cluster-banner {
    background: var(--cluster-accent-soft);
    border-bottom: 1px solid var(--color-rule);
    padding: 14px 0;
  }
  .ak-cluster-banner .inner {
    max-width: 1240px; margin: 0 auto; padding: 0 40px;
    display: flex; justify-content: space-between; align-items: center;
    gap: 24px;
    font-family: var(--font-mono);
    font-size: 11px; letter-spacing: 0.14em; text-transform: uppercase;
    color: var(--cluster-accent);
  }
  .ak-cluster-banner .inner .nav { display: flex; gap: 28px; }
  .ak-cluster-banner .inner .nav a {
    color: inherit; text-decoration: none;
    opacity: 0.65; transition: opacity 150ms ease;
  }
  .ak-cluster-banner .inner .nav a:hover,
  .ak-cluster-banner .inner .nav a.active { opacity: 1; }

  /* Pillar lead — headline + CTA side by side; paragraph never collides with button */
  .pillar-lead {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    gap: 40px;
    align-items: end;
    border-bottom: 1px solid var(--color-rule);
    padding-bottom: 28px;
    margin: 48px 0 8px;
  }
  .pillar-lead .lead-text { min-width: 0; }
  .pillar-lead .kicker {
    font-family: var(--font-mono);
    font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase;
    color: var(--cluster-accent);
    display: block; margin-bottom: 14px;
  }
  .pillar-lead h1 {
    font-family: var(--font-display);
    font-variation-settings: "opsz" 144;
    font-size: clamp(40px, 5vw, 60px);
    font-weight: 500; line-height: 1.02;
    letter-spacing: -0.02em;
    margin: 0;
  }
  .pillar-lead .dek {
    margin: 18px 0 0;
    max-width: 58ch;
    font-family: var(--font-body);
    font-size: 15.5px; line-height: 1.55;
    color: var(--color-text-secondary);
  }
  .pillar-lead .lead-cta {
    font-family: var(--font-mono);
    font-size: 11px; letter-spacing: 0.1em; text-transform: uppercase;
    color: var(--cluster-accent-ink);
    background: var(--cluster-accent);
    padding: 14px 22px;
    white-space: nowrap;
    text-decoration: none;
    align-self: end;
    transition: filter 150ms ease;
  }
  .pillar-lead .lead-cta:hover { filter: brightness(0.92); }

  /* Philosophy — full-width principles, compact mono label up top (no wasted column) */
  .ak-philosophy {
    margin: 56px 0 8px;
  }
  .ak-philosophy .philosophy-head {
    display: grid;
    grid-template-columns: auto 1fr;
    align-items: center;
    gap: 20px;
    margin-bottom: 28px;
  }
  .ak-philosophy .lbl {
    font-family: var(--font-mono);
    font-size: 10.5px; letter-spacing: 0.14em; text-transform: uppercase;
    color: var(--color-text-muted);
    display: inline-block;
  }
  .ak-philosophy .philosophy-head .rule {
    display: block; height: 1px;
    background: var(--color-rule);
  }
  .ak-philosophy .principles {
    display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 40px;
  }
  .ak-philosophy .principle .num {
    font-family: var(--font-display);
    font-variation-settings: "opsz" 144;
    font-size: 40px; line-height: 1;
    color: var(--cluster-accent);
    font-weight: 400; font-style: italic;
    display: block; margin-bottom: 14px;
  }
  .ak-philosophy .principle .ttl {
    font-family: var(--font-display);
    font-size: 19px; font-weight: 500; line-height: 1.25;
    margin: 0 0 8px; letter-spacing: -0.005em;
  }
  .ak-philosophy .principle p {
    font-family: var(--font-body);
    font-size: 14px; line-height: 1.55;
    color: var(--color-text-secondary); margin: 0;
  }

  /* Section header for tier rows */
  #tranchen { margin-top: 24px; }
  .ak-tier-header {
    display: grid;
    grid-template-columns: 140px 1fr;
    gap: 28px;
    align-items: baseline;
    margin: 64px 0 20px;
    padding-top: 16px;
    border-top: 1px solid var(--color-text-primary);
    position: relative;
  }
  #tranchen > :first-child.ak-tier-header { margin-top: 48px; }
  .ak-tier-header::before {
    content: "";
    position: absolute; left: 0; top: -1px;
    width: 140px; height: 3px;
    background: var(--sev, var(--cluster-accent));
  }
  .ak-tier-header .age {
    font-family: var(--font-display);
    font-variation-settings: "opsz" 144;
    font-size: 72px; line-height: 0.95;
    color: var(--sev, var(--color-text-primary));
    font-weight: 600; letter-spacing: -0.02em;
    margin: 0;
  }
  .ak-tier-header .text h2 {
    font-family: var(--font-display);
    font-variation-settings: "opsz" 72;
    font-size: clamp(22px, 2.2vw, 28px);
    font-weight: 500; margin: 0 0 8px;
    line-height: 1.2; letter-spacing: -0.005em;
  }
  .ak-tier-header .text .tag {
    font-family: var(--font-mono);
    font-size: 10.5px; letter-spacing: 0.12em; text-transform: uppercase;
    color: var(--sev, var(--cluster-accent));
    margin-bottom: 8px; display: block;
  }
  .ak-tier-header .text p {
    font-family: var(--font-body);
    font-size: 14.5px; line-height: 1.55;
    color: var(--color-text-secondary);
    margin: 0; max-width: 62ch;
  }

  /* FAQ */
  .ak-faq { margin: 80px 0 40px; }
  .ak-faq > header {
    display: grid; grid-template-columns: 1fr auto; align-items: baseline;
    border-top: 1px solid var(--color-text-primary);
    padding-top: 16px; margin-bottom: 24px;
  }
  .ak-faq > header h2 {
    font-family: var(--font-display);
    font-variation-settings: "opsz" 144;
    font-size: clamp(28px, 3vw, 36px);
    font-weight: 500; margin: 0;
    letter-spacing: -0.01em; line-height: 1.1;
  }
  .ak-faq > header .lbl {
    font-family: var(--font-mono);
    font-size: 10.5px; letter-spacing: 0.12em; text-transform: uppercase;
    color: var(--cluster-accent);
  }
  .ak-faq .list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 0 48px; }
  .ak-faq details {
    border-top: 1px solid var(--color-rule);
    padding: 18px 0;
  }
  .ak-faq details:last-child { border-bottom: 1px solid var(--color-rule); }
  .ak-faq summary {
    list-style: none;
    cursor: pointer;
    display: flex; justify-content: space-between; align-items: baseline;
    gap: 16px;
    font-family: var(--font-display);
    font-variation-settings: "opsz" 72;
    font-size: 17px; font-weight: 500; line-height: 1.35;
    color: var(--color-text-primary);
  }
  .ak-faq summary::-webkit-details-marker { display: none; }
  .ak-faq summary::after {
    content: "+";
    font-family: var(--font-mono);
    font-size: 18px; color: var(--cluster-accent);
    flex: 0 0 auto;
    transition: transform 150ms ease;
  }
  .ak-faq details[open] summary::after { content: "—"; }
  .ak-faq details p {
    font-family: var(--font-body);
    font-size: 14px; line-height: 1.6;
    color: var(--color-text-secondary);
    margin: 12px 0 0; max-width: 58ch;
  }

  @media (max-width: 960px) {
    .pillar-lead { grid-template-columns: 1fr; gap: 20px; align-items: start; }
    .pillar-lead .lead-cta { justify-self: start; align-self: start; }
    .ak-philosophy .principles { gap: 28px; }
    .ak-tier-header { grid-template-columns: 1fr; gap: 12px; }
    .ak-tier-header .age { font-size: 52px; }
    .ak-faq .list { grid-template-columns: 1fr; gap: 0; }
  }
  @media (max-width: 720px) {
    .ak-philosophy .principles { grid-template-columns: 1fr; }
  }
  @media (max-width: 560px) {
    .pillar-lead { margin: 28px 0 4px; padding-bottom: 20px; gap: 16px; }
    .pillar-lead h1 { font-size: clamp(32px, 9vw, 44px); line-height: 1.05; }
    .pillar-lead .dek { font-size: 15px; }
    .pillar-lead .lead-cta { padding: 12px 18px; font-size: 10.5px; }
    .ak-philosophy { margin: 36px 0 4px; }
    .ak-philosophy .philosophy-head { margin-bottom: 18px; gap: 14px; }
    #tranchen > :first-child.ak-tier-header { margin-top: 28px; }
  }