nav.chapter-nav{--marker:6px;--marker-pad:8px;--chapter-gap:24px;--chapter-inset:max(var(--frame-edge),calc((100% - var(--frame-max)) / 2 + var(--frame-edge)));--rail-color:var(--line-strong);position:sticky;top:0;z-index:20;padding:0;overflow:visible;border-bottom:1px solid var(--line);background:color-mix(in srgb,var(--paper) 95%,transparent);backdrop-filter:blur(12px)}nav.chapter-nav ol{position:relative;display:flex;gap:0;width:100%;min-width:0;max-width:none;margin:0;padding:6px var(--chapter-inset);list-style:none;overflow-x:auto;overflow-y:hidden;overscroll-behavior-x:contain;scroll-padding-inline:var(--chapter-inset) max(44px,var(--chapter-inset));scrollbar-width:none}nav.chapter-nav ol::-webkit-scrollbar{display:none}nav.chapter-nav li{position:relative;display:flex;flex:none;margin:0;padding:0 var(--chapter-gap) 0 0}nav.chapter-nav li:last-child{padding-right:0}nav.chapter-nav li[data-rail=passed]{--rail-color:var(--accent)}nav.chapter-nav li:before{content:"";position:absolute;left:calc(var(--marker) / 2);right:calc(var(--marker) / -2);bottom:calc(var(--marker-pad) + var(--marker) / 2 - 1px);height:2px;background:repeating-linear-gradient(90deg,var(--rail-color) 0 3px,transparent 3px 4px)}nav.chapter-nav li:last-child:before{content:none}nav.chapter-nav a{position:relative;z-index:1;display:flex;flex-direction:column;align-items:flex-start;justify-content:flex-start;gap:8px;min-height:44px;margin:0;padding:6px 0 var(--marker-pad);color:var(--muted);font:400 var(--step--1)/16px var(--font-body),sans-serif;letter-spacing:0;white-space:nowrap;text-decoration:none;transition:color .2s var(--ease-out)}nav.chapter-nav a:after{content:"";flex:none;width:var(--marker);height:var(--marker);background:var(--line-strong)}nav.chapter-nav a[aria-current=location]:after,nav.chapter-nav li[data-rail=passed] a:after{background:var(--accent)}nav.chapter-nav a[aria-current=location]{color:var(--ink)}nav.chapter-nav a[aria-current=location]:after{box-shadow:0 0 0 2px color-mix(in srgb,var(--accent) 32%,var(--paper))}@media (hover:hover) and (pointer:fine){nav.chapter-nav a:hover{color:var(--ink);text-decoration:none}nav.chapter-nav li:not([data-rail]) a:hover:after{background:var(--muted)}}nav.chapter-nav a:focus-visible{color:var(--ink)}nav.chapter-nav:after,nav.chapter-nav:before{content:"";position:absolute;z-index:2;top:0;bottom:0;width:32px;opacity:0;pointer-events:none;transition:opacity .2s var(--ease-out)}nav.chapter-nav:before{left:0;background:linear-gradient(to left,transparent,var(--paper))}nav.chapter-nav:after{right:0;background:linear-gradient(to right,transparent,var(--paper))}nav.chapter-nav[data-less=true]:before,nav.chapter-nav[data-more=true]:after{opacity:1}@media (max-width:1099px){nav.chapter-nav:not([data-more]):after{opacity:1}}@media (prefers-reduced-motion:reduce){nav.chapter-nav a,nav.chapter-nav:after,nav.chapter-nav:before{transition:none}}@media print{nav.chapter-nav{display:none}}