.chapter-page{--chapter-accent: #98bbb0;width:min(960px,100%);margin-inline:auto;padding:24px 32px 0}.chapter-heading{margin-bottom:36px}.chapter-number{margin:0 0 12px;color:var(--muted);font-size:12px;letter-spacing:.16em}.chapter-heading h1{margin:0;font-size:clamp(26px,4.5vw,40px);font-weight:500;letter-spacing:.04em}.chapter-lead{margin:14px 0 0;color:var(--muted);line-height:1.8}.chapter-tabs{display:grid;grid-auto-flow:column;grid-auto-columns:minmax(0,1fr);border-bottom:1px solid #45464b}.chapter-tab{display:flex;align-items:center;justify-content:center;gap:14px;padding:18px 10px;border:0;border-bottom:2px solid transparent;margin-bottom:-1px;background:transparent;color:var(--muted);font:inherit;text-align:left;cursor:pointer}.tab-initial{font:38px/1 Georgia,serif}.chapter-tab small{display:block;margin-top:4px;font-size:12px}.chapter-tab:hover{background:#202227;color:var(--chapter-accent)}.chapter-tab[aria-selected=true]{border-bottom-color:var(--chapter-accent);color:var(--chapter-accent)}.chapter-tab:focus-visible,.chapter-panel:focus-visible{outline:2px solid var(--chapter-accent);outline-offset:4px}.chapter-panel{padding-top:32px}.chapter-panel[hidden]{display:none}.lesson-stage{padding:32px 0 48px}.lesson-heading{max-width:760px;margin-bottom:28px}.lesson-stage .lesson-eyebrow{margin:0 0 10px;color:var(--chapter-accent);font-size:12px;line-height:1.9;letter-spacing:.1em}.lesson-heading .lesson-title{margin:0;font-size:clamp(24px,4vw,30px);font-weight:500;line-height:1.6}.lesson-heading .lesson-description{margin:14px 0 0;color:var(--muted);font-size:15px;line-height:1.9}.lesson-details{margin-top:24px;font-size:13px;line-height:1.9}.lesson-details summary{width:fit-content;cursor:pointer;color:var(--chapter-accent);text-underline-offset:4px}.lesson-details summary:hover{text-decoration:underline}.lesson-details summary:focus-visible,.lesson-sources a:focus-visible{outline:2px solid var(--chapter-accent);outline-offset:4px}.lesson-sources a{color:var(--muted);overflow-wrap:anywhere;text-underline-offset:3px}.lesson-sources a:hover{color:var(--ink)}.lesson-sources ul{padding-left:20px}.lesson-sources li+li{margin-top:10px}.chapter-page .chapter-navigation{margin-top:auto}@media(max-width:540px){.chapter-page{padding:24px 20px 0}.chapter-heading{margin-bottom:24px}.chapter-tab{gap:8px;padding:16px 4px;font-size:14px}.tab-initial{font-size:30px}.lesson-stage{padding-top:20px}}