:root{--navy:#173e92;--teal:#255cf4;--gold:#5888ff;--muted:#71809a;--line:#e0e7f3;background:#f7f9fd;color:#172d51;font-family:'DM Sans','Segoe UI',sans-serif}body{line-height:1.6}h1,h2,h3,h4{font-family:Manrope,'Segoe UI',sans-serif}.lesson-topbar{height:80px;padding:0 32px;position:relative;z-index:5}.lesson-topbar .wordmark{font-size:25px}.lesson-location{margin-right:auto;margin-left:18px;color:#667897;font-size:13px}.lesson-location span{color:#b9c6dc;margin:0 11px}.lesson-topbar nav{display:flex;gap:24px;align-items:center}.lesson-topbar nav a{font-size:13px;color:#7283a0}.lesson-topbar nav a:last-child{color:#255cf4}.layout{max-width:none;grid-template-columns:264px minmax(0,1fr)}.layout>aside{background:white;border-right:1px solid #e1e8f3;padding:35px 24px}.layout>aside>.eyebrow{color:#5379da;font-size:12px;letter-spacing:.14em}.layout>aside h1{font-size:23px;color:#19305a;line-height:1.3}.layout>aside .intro{font-size:13px;line-height:1.7}.layout>aside .session-note{font-size:12px;color:#96a3b7}#units{gap:6px;margin-top:25px}#units a{font-size:13px;line-height:1.4;border-radius:9px;padding:12px 10px;color:#73849d}#units a span{font-size:12px;color:#9baac1}#units a[aria-current]{background:#edf2ff;color:#255cf4;border-color:#e1e9ff;box-shadow:none}#units a[aria-current] span{color:#255cf4}#units a:hover{background:#f4f7fc}.layout>main{width:100%;max-width:1240px;margin:0 auto;padding:37px clamp(24px,3.5vw,60px) 65px}.layout>main>h2{font-size:clamp(28px,3.1vw,42px);color:#152c57;line-height:1.2;margin-top:8px}.layout>main>.eyebrow{color:#7492ca;font-size:12px;letter-spacing:.13em}.lead{font-size:16px;color:#7a8ba6;line-height:1.75}.lesson-meta{margin-bottom:27px}.pill{border-color:#dce6ff;background:#edf3ff;color:#5278d1;font-size:12px}.bridge{border-color:#7198ff;background:#edf3ff;border-radius:0 10px 10px 0}.teaching{background:white;border:1px solid #e3eaf5;border-radius:17px;padding:28px;gap:26px;box-shadow:0 4px 18px #15346a03}.explanation>.eyebrow{font-size:12px;color:#7893bd;letter-spacing:.11em}.explanation h3{font-size:23px;line-height:1.3;margin:8px 0 17px;letter-spacing:-.03em;color:#213b66}.segment-text{font-size:16px;line-height:1.85;color:#526580}.segment-nav button,.quiet{border-color:#dce5f4;border-radius:8px;background:#f7f9fd;font-size:13px}.segment-nav button:hover:not(:disabled){background:#edf2ff;color:#255cf4}.audio{background:#f6f8fd;border-radius:10px;padding:13px;margin-top:20px}.audio p{font-size:12px;margin:5px 0}.audio details{font-size:13px;color:#7486a3}.audio audio{height:36px}.visual{border-radius:12px;background:radial-gradient(ellipse at 0 0,#2255b0,#132d64 75%);padding:23px}.visual h4{font-size:16px;font-weight:600}.visual label{font-size:14px}.visual input[type=range]{accent-color:#9dc3ff}.visual output{color:#bfd8ff}.section{padding-top:30px;margin-top:30px}.section>h3{font-size:23px;color:#243b62}.exam-notes{background:#edf3ff;border:1px solid #e1e9fa;border-radius:12px;padding:23px;gap:22px;line-height:1.8;color:#526988}.exam-notes h4{font-size:15px;color:#3466d0}.worked{border:1px solid #dce7fb;border-left:3px solid #7198ff;border-radius:12px;padding:25px;background:white;box-shadow:none}.worked h4{font-size:19px}.answer-box{background:#edf3ff;border-radius:8px;color:#4a67a0}.activity{padding:26px;border-radius:14px;border-color:#e0e7f3}.activity .eyebrow{font-size:12px;color:#7892b9}.activity h4{font-size:20px;letter-spacing:-.03em;margin-top:7px}.activity .prompt{font-size:16px;color:#405779}.activity .origin{font-size:12px;font-weight:400;color:#8b9bb3}.choice{border-color:#e0e7f3;border-radius:9px;padding:14px;color:#506480}.choice:has(input:checked){border-color:#86a7ff;background:#f0f5ff}.choice input{accent-color:#255cf4}.primary{background:#255cf4;color:white;border-radius:9px;font-size:14px;padding:12px 19px}.primary:hover{background:#1749dc}.feedback{border-radius:0 10px 10px 0;background:#edf3ff;border-color:#7da2ff}.hint{color:#496795}.entry input,.entry select,textarea{border-radius:8px;border-color:#d8e1f0}.checkpoint{background:#f0f5ff;border-color:#88aafa;border-radius:0 9px 9px 0}.next-lesson{padding-top:22px;border-top:1px solid #dfe7f5}.next-lesson a{font-size:14px;color:#3b68ca}.assessment-note{background:#eaf1ff;border:1px solid #dce7fe}.lesson-topbar~footer{font-size:12px;background:white;border-color:#e0e7f3;color:#8d9cb2}.layout>aside .quiet{font-size:12px}.planet-story,.solar-story{border-radius:14px}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #5888ff;outline-offset:4px}
@media(max-width:1150px){.layout{grid-template-columns:230px minmax(0,1fr)}.layout>aside{padding:28px 17px}.teaching{grid-template-columns:1fr;padding:24px}.visual{max-width:none}.lesson-location{margin-left:5px}}
@media(max-width:850px){.lesson-location{display:none}.lesson-topbar{padding:0 23px}.lesson-topbar nav{gap:15px}.layout{grid-template-columns:210px minmax(0,1fr)}.layout>aside{padding:25px 15px}.layout>main{padding:28px 23px 50px}.exam-notes{grid-template-columns:1fr}}
@media(max-width:720px){.lesson-topbar{height:auto;min-height:72px;padding:18px 20px;flex-wrap:wrap;gap:13px}.lesson-topbar .wordmark{font-size:23px}.lesson-topbar .wordmark img{width:33px;height:33px}.lesson-topbar nav{gap:15px}.lesson-topbar nav a{font-size:12px}.layout{display:block}.layout>aside{padding:21px 20px;border-right:0}.layout>aside h1{font-size:21px}.layout>aside .intro{display:block;margin:6px 0 0;font-size:13px}#units{margin-top:18px}#units a{flex-basis:155px;border:1px solid #e5ecf7;background:#f8faff;font-size:12px;padding:11px}.layout>aside .session-note{font-size:12px;margin-top:12px}.layout>main{padding:27px 18px 45px}.layout>main>h2{font-size:29px}.teaching{padding:20px;border-radius:13px}.explanation h3{font-size:22px}.segment-text{line-height:1.8}.activity,.worked{padding:21px}.exam-notes{padding:20px}.lesson-topbar~footer{padding:22px;font-size:12px}}