/* Four restrained chapter marks at the left edge; no extra row in the page. */
.chapter-nav{position:fixed;left:12px;top:50%;transform:translateY(-50%);width:38px;height:auto;min-height:0;margin:0;padding:0;border:0;background:none;z-index:30;opacity:0;visibility:hidden;transition:opacity .2s ease,visibility .2s}
.chapter-nav.is-visible{opacity:1;visibility:visible}
.chapter-content-frame{display:flex;flex-direction:column;gap:8px;min-height:0;height:auto;padding:0;width:100%;margin:0}
.chapter-nav .chapter:nth-child(n){position:relative;display:flex;align-items:flex-start;justify-content:center;flex-direction:column;width:38px;height:40px;padding:0;border:0;background:none}
.chapter-nav .chapter small{display:none}
.chapter-nav .chapter::after{content:'';display:block;position:static;width:20px;height:3px;background:#939b97;transform:scaleX(1);transform-origin:left center;transition:transform .32s cubic-bezier(.2,.7,.3,1),background-color .2s}
.chapter-nav .chapter.current::after{width:20px;background:#ffd000;transform:scaleX(1.7)}
.chapter-nav .chapter-label{position:absolute;left:44px;top:50%;transform:translate(5px,-50%);padding:7px 9px;font:600 10px/1.2 Manrope,Arial,sans-serif;letter-spacing:.03em;background:#f8f8f7;color:#141b17;white-space:nowrap;opacity:0;pointer-events:none;transition:opacity .16s,transform .16s}
.chapter-nav .chapter:focus-visible{outline:1px solid #ffd000;outline-offset:2px}
.chapter-nav .chapter:focus-visible .chapter-label{opacity:1;transform:translate(0,-50%)}
@media(hover:hover){.chapter-nav .chapter:hover .chapter-label{opacity:1;transform:translate(0,-50%)}.chapter-nav .chapter:hover::after{background:#ffd000}}
@media(max-width:700px){
 .chapter-nav{display:none}
}
@media(prefers-reduced-motion:reduce){.chapter-nav,.chapter-nav .chapter::after,.chapter-nav .chapter-label{transition:none}}