.course-switch{display:flex;gap:10px;margin:0 0 22px;flex-wrap:wrap}.course-switch button{display:flex;gap:12px;align-items:center;min-height:44px}.course-switch small{font-size:11px;color:var(--muted)}.course-switch .selected{background:#dce5e4;border-color:#9eb8bd}.course-switch .selected:before{content:'✓';font-size:13px}.string-index-strip{display:flex;gap:8px;flex-wrap:wrap;margin:22px 0}.string-index-strip>span{display:flex;flex-direction:column;align-items:center;border:1px solid var(--line);min-width:48px;border-radius:5px;background:var(--paper);overflow:hidden;transition:background .2s,border-color .2s}.string-index-strip small{width:100%;text-align:center;background:var(--soft);padding:4px;font-size:11px}.string-index-strip b{font:24px Georgia,serif;padding:10px 14px}.string-index-strip .selected{background:#dce5e4;border-color:#718f90}.string-index-strip .selected b{text-decoration:underline;text-underline-offset:5px}@media(max-width:650px){.course-switch{gap:6px}.course-switch button{flex:1;flex-direction:column;gap:3px}.course-switch .selected:before{display:none}.string-index-strip{gap:5px}.string-index-strip>span{min-width:38px}.string-index-strip b{padding:8px 10px}}@media(prefers-reduced-motion:reduce){.string-index-strip>span{transition:none}}

.unit2-active .learn-intro,.unit2-active .home-strip{display:none}.unit2-active .study-grid{margin-top:0}@media(min-width:901px){.unit2-active .trace-layout{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,1fr);gap:16px}.unit2-active .trace-inspector{display:block}.unit2-active .trace-code{min-width:0}.unit2-active .trace-line code{white-space:pre-wrap;overflow-wrap:anywhere}}