/* R152: keep a natural Library return available throughout the original text. */
.book-page .campus-header{position:sticky;top:0;z-index:20;max-width:none;padding:8px 24px;background:#10232cf5;box-shadow:0 3px 14px #0004;gap:10px 24px;backdrop-filter:blur(8px)}
.book-page .campus-brand{font-size:21px}.book-page .campus-brand span{font-size:11px;margin-top:3px}
.book-page .campus-header nav{gap:8px 24px}.book-page .campus-header nav a{font-size:15px;text-decoration:underline;text-underline-offset:4px}
.book-page .book-page-text,.book-page .page-index,.book-page #book-text{scroll-margin-top:var(--reader-clearance,90px)}
.book-page .page-index:focus-visible{outline:3px solid #ffe2a3;outline-offset:4px}
@media(max-width:600px){.book-page .campus-header{padding:4px 16px}.book-page .campus-header>.campus-brand{display:none}.book-page .campus-header nav{width:100%;justify-content:space-between;gap:4px 12px}.book-page .campus-header nav a{font-size:14px}}
@media(max-height:420px){.book-page .campus-header>.campus-brand{display:none}.book-page .campus-header{padding-block:3px}}
@media(forced-colors:active){.book-page .campus-header{background:Canvas;border-bottom:1px solid CanvasText;box-shadow:none}}
@media print{.book-page .campus-header{position:static;box-shadow:none;backdrop-filter:none}}
/* Chapter labels use the existing page anchors and remain readable at phone width. */
.chapter-index nav{grid-template-columns:repeat(auto-fit,minmax(min(100%,170px),1fr))}
.chapter-index a{padding:12px;gap:3px;flex-direction:column;align-items:flex-start;justify-content:center;text-align:left;line-height:1.35}.chapter-index a small{opacity:.85}