/* Quiet index. Shared desktop rail and mobile disclosure. */
.final-preview .case-layout{grid-template-columns:200px minmax(0,1fr);gap:48px}
.chapter-nav{position:sticky;top:112px;align-self:start;min-width:0;font-size:var(--ds-type-nav);color:var(--ink);z-index:19}
.chapter-eyebrow{font-size:var(--ds-type-meta);line-height:1.5;color:var(--muted);margin-bottom:20px}
.chapter-list{display:flex;flex-direction:column;gap:4px;border-left:1px solid var(--line)}
.chapter-list a{display:flex;align-items:center;min-height:44px;padding:10px 16px;line-height:1.5;color:var(--muted);position:relative;touch-action:manipulation}
.chapter-list a.is-current{color:var(--ink);font-weight:600}
.chapter-list a.is-current:before{content:'';position:absolute;left:-1px;top:10px;bottom:10px;width:2px;background:var(--ink)}
.chapter-list a:hover{color:var(--ink);background:#eeeef0}
.chapter-current{display:none}
.chapter-toggle{display:flex;align-items:center;gap:12px;min-height:48px;width:100%;text-align:left;padding:8px 0;font-size:var(--ds-type-nav);touch-action:manipulation}
.chapter-toggle svg{width:20px;height:20px;flex:none;margin-left:auto;transition:transform .18s}
.chapter-nav.is-open .chapter-toggle svg{transform:rotate(180deg)}
.chapter-current-label{font-weight:550;flex:1}
.chapter-nav button:focus-visible,.chapter-nav a:focus-visible{outline:2px solid var(--ink);outline-offset:-2px}
.final-preview .pm3{--pm3-top:var(--ds-anchor-offset)}
@media(max-width:760px){
  .final-preview .case-layout{display:block}
  .chapter-nav{top:var(--ds-header-height,68px);margin-bottom:32px;margin-inline:calc(-1 * var(--gutter));padding-inline:var(--gutter);background:color-mix(in srgb,var(--bg) 96%,transparent);backdrop-filter:blur(16px);border-bottom:1px solid var(--line)}
  .chapter-eyebrow{display:none}
  .chapter-current{display:block}
  .chapter-list{display:none;border-left:0;gap:8px}
  .chapter-list a{padding:10px 14px}
  .chapter-list a.is-current:before{left:0}
  .chapter-nav.is-open .chapter-list{display:flex;position:absolute;left:var(--gutter);right:var(--gutter);top:100%;padding:12px;background:var(--bg);border:1px solid var(--ds-edge);border-radius:0 0 var(--ds-radius) var(--ds-radius);box-shadow:0 12px 28px #0000000a;max-height:60dvh;overflow:auto}
}