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.notes{position:fixed;right:16px;bottom:92px;z-index:80;width:min(360px,calc(100vw - 32px));padding:18px;border:1px solid var(--line);border-radius:18px;background:var(--surface);box-shadow:var(--shadow)}.notes textarea{width:100%;padding:10px;border:1px solid var(--line)}.player{position:fixed;z-index:60;left:0;right:0;bottom:0;height:68px;display:grid;grid-template-columns:auto minmax(0,1fr) auto;align-items:center;gap:14px;padding:9px clamp(14px,3vw,32px);background:var(--deep);color:white}.player button{width:44px;height:44px;border:0;border-radius:50%;background:var(--accent);color:white;cursor:pointer}.player div{overflow:hidden}.player b,.player small{display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.player small{color:#aac1b8}.player a{color:white;text-decoration:none;font-weight:800}
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@media(max-width:620px){.crumb{display:none}.topbar{grid-template-columns:1fr auto}.hero{min-height:auto;padding-top:30px}.hero h1{font-size:clamp(2.55rem,11vw,3.25rem)}.hero-card{min-height:330px}.heading h2,.assignment h2,.next-chapter h2{font-size:clamp(2rem,9vw,2.65rem)}.divider{padding-block:55px}.divider h2{font-size:clamp(2.1rem,9.5vw,2.8rem)}.viewer-wrap{min-height:390px}.learning-viewer-wrap{min-height:430px}.compare-viewer{height:300px}.content{padding-bottom:95px}.player{grid-template-columns:auto 1fr}.player a{display:none}.lesson-tab{min-width:168px}.lesson-detail{min-height:0}.next-chapter{padding:38px 28px}.learning-tabs button{font-size:12px}.view-controls button{flex-basis:calc(50% - 5px)}}
@media(pointer:coarse){.learning-lab button,.learning-lab input[type=range]{min-height:48px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*{transition:none!important}}