.section-stack{position:relative}.section-stack__viewport{min-height:200px}.section-stack__separator{display:block}.chapter-strip{display:flex;width:100%;align-items:stretch;gap:0;padding:0;border-bottom:1px solid var(--color-border-subtle)}.chapter-strip__cell{position:relative;flex:1 1;display:inline-flex;align-items:center;justify-content:center;gap:var(--space-xs);height:60px;padding:0;border:none;background:transparent;color:var(--color-text-subtle);font-family:var(--font-display);font-size:var(--text-body-lg);font-weight:500;letter-spacing:-.005em;line-height:1;cursor:pointer;transition:color .2s ease}.chapter-strip__cell:hover{color:var(--color-text-primary)}.chapter-strip__cell:focus-visible{outline:var(--focus-ring-outline);outline-offset:4px}.chapter-strip__count{font-family:var(--font-mono);font-size:var(--text-body-sm);font-weight:500;letter-spacing:0;color:var(--color-text-subtle);transition:color .2s ease;transform:translateY(-1px)}.chapter-strip__cell .chapter-strip__count:before{content:"\00B7";margin-right:var(--space-xs);color:var(--color-text-disabled)}.chapter-strip__cell--active{font-weight:600}.chapter-strip__cell--active,.chapter-strip__cell--active .chapter-strip__count{color:var(--color-text-primary)}.chapter-strip__cell--active:before{content:"";position:absolute;left:0;right:0;bottom:-1px;height:2px;background:var(--color-text-primary)}@media (max-width:768px){.chapter-strip__cell{height:56px;font-size:var(--text-body-md)}.chapter-strip__count{font-size:var(--text-label-md)}}