.course-switcher{position:sticky;top:91px;z-index:9;display:flex;align-items:stretch;gap:6px;padding:8px max(4.5%,calc((100vw - 1274px)/2));border-bottom:1px solid #dce1ec;background:#f5f6faf7;min-height:62px;overflow-x:auto;scrollbar-width:thin}.course-label{align-self:center;font-size:10px;font-weight:700;letter-spacing:1.6px;color:#66728a;margin-right:20px;white-space:nowrap}.course-switcher a{display:flex;align-items:center;gap:10px;white-space:nowrap;border-radius:7px;padding:8px 15px;text-decoration:none;color:#637086;font-size:13px;border:1px solid transparent}.course-switcher a strong{font-size:13px;font-weight:500}.course-switcher a:hover{background:#e8edf8}.course-switcher a[aria-current=page]{color:#2e43c4;background:#e7ebfc;border-color:#d1d9f5}.course-switcher a[aria-current=page] span{font-weight:700}.sidebar{top:188px;max-height:calc(100dvh - 208px)}html{scroll-padding-top:177px}.archive{position:relative;z-index:8}.archive-entry+.archive-entry{margin-top:12px}.archive-entry[aria-current=page]{border-color:#8b9cef;background:#f5f7ff}.lesson-navigation{display:grid;grid-template-columns:1fr 1fr;gap:18px;border-top:1px solid var(--line);padding:30px 0}.lesson-navigation>a,.lesson-navigation>div{display:block;border:1px solid #dce2ef;padding:22px;border-radius:12px;text-decoration:none;background:#fff}.lesson-navigation>a{transition:background .2s,transform .2s,border-color .2s}.lesson-navigation>a:hover{background:#eaf0ff;transform:translateY(-2px);border-color:#aebeea}.lesson-navigation span{display:block;font-size:10px;letter-spacing:1.5px;color:#66728a;margin-bottom:10px}.lesson-navigation strong{font:500 22px/1.3 var(--display);color:#26386d}.lesson-navigation>div{background:transparent;border-style:dashed}.lesson-navigation>div strong{color:#67718a;font-size:18px}@media(max-width:800px){.course-switcher{top:76px;padding:8px 5%}.course-label{display:none}.course-switcher a{flex:1;justify-content:center;padding:7px 10px;font-size:12px}.course-switcher a strong{font-size:12px}html{scroll-padding-top:153px}}@media(max-width:480px){.course-switcher a{flex-direction:column;gap:1px;font-size:12px}.course-switcher a strong{font-size:11px}.lesson-navigation{grid-template-columns:1fr;gap:12px}.lesson-navigation>a,.lesson-navigation>div{padding:19px}}@media print{.course-switcher,.lesson-navigation{display:none}}

/* Keep the numbered class choices visible on a narrow screen. */
@media(max-width:480px){.course-switcher{gap:4px}.course-switcher a{flex:1 1 0;min-width:0;padding:7px 5px}.course-switcher a strong{font-size:10px;max-width:100%;overflow:hidden;text-overflow:ellipsis}.course-switcher a span{font-size:11px}}
@media(max-width:480px){.course-switcher a .class-word{display:none}.course-switcher a>span{font-weight:700}.course-switcher a{padding-inline:3px}}