:root{--paper:#f7f5ed;--card:#fffef9;--ink:#203b39;--muted:#566c66;--green:#234f47;--mint:#e2eadb;--line:#d4dbcf;--orange:#a74727;--soft:#f5e7dc}
*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.65 system-ui,-apple-system,sans-serif}
button,input,textarea{font:inherit}button,a{touch-action:manipulation}button{cursor:pointer;color:inherit;background:transparent;border:1px solid var(--line);border-radius:8px;padding:10px 16px;line-height:1.4}button:hover{background:var(--mint)}button:disabled{opacity:.4;cursor:default}button:focus-visible,a:focus-visible,textarea:focus-visible{outline:3px solid var(--orange);outline-offset:3px}
button.primary{background:var(--green);color:white;border-color:var(--green)}button.primary:hover{background:#32695e}button[aria-pressed=true]{background:var(--green);color:white;border-color:var(--green)}
a{color:var(--green)}h1,h2,h3,p{margin:0}h1,h2{font-family:Georgia,serif;font-weight:400;line-height:1.15}h1{font-size:clamp(34px,4.5vw,64px);letter-spacing:-1.8px}h2{font-size:clamp(28px,3vw,40px);letter-spacing:-.7px}h3{font-size:19px;line-height:1.4}p+p{margin-top:20px}
small,.small{font-size:13px;color:var(--muted)}.eyebrow{font-size:12px;font-weight:700;letter-spacing:1.8px;text-transform:uppercase;color:var(--orange)}.muted{color:var(--muted)}.row{display:flex;flex-wrap:wrap;gap:10px;align-items:center}.spaced{justify-content:space-between}.stack{display:grid;gap:22px}.hidden,[hidden]{display:none!important}
header{position:sticky;top:0;z-index:5;background:var(--paper);border-bottom:1px solid var(--line);padding:14px 26px;display:flex;justify-content:space-between;gap:20px;align-items:center}.brand{font-family:Georgia,serif;font-size:25px;border:0;padding:0;letter-spacing:-.6px}.brand:hover{background:none}.brand span{color:var(--orange)}header .small{font-size:12px}
.shell{display:grid;grid-template-columns:245px minmax(0,1fr);max-width:1580px;margin:auto}
aside{padding:25px 18px;border-right:1px solid var(--line);position:sticky;top:77px;height:calc(100vh - 77px);overflow:auto}
aside nav{display:grid;gap:5px}aside button{text-align:left;border-color:transparent;font-size:14px;padding:9px 11px}aside button.current{background:var(--mint);font-weight:600}
aside .module{margin:22px 10px 8px;font-size:11px;letter-spacing:1.2px;text-transform:uppercase;color:var(--muted)}aside .num{display:inline-block;color:var(--orange);width:38px;font-size:12px;vertical-align:top}
.side-title{display:block;line-height:1.35}.navitem{display:grid;grid-template-columns:38px 1fr!important}.done{color:var(--green)}
main{padding:34px clamp(20px,4vw,64px) 60px;min-width:0}main>section{max-width:1080px;margin:auto}.hero{display:grid;grid-template-columns:1.1fr 1fr;gap:36px;align-items:center;margin:16px 0 40px}.hero img{width:100%;border-radius:2px}.hero figure{margin:0}.hero figcaption{font-size:12px;color:var(--muted);margin-top:9px}.intro{font-size:18px;color:var(--muted);margin:22px 0;max-width:600px}.tag{display:inline-block;padding:4px 10px;border-radius:4px;background:var(--mint);font-size:12px}
.path{margin:32px 0}.path-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line);border:1px solid var(--line);border-radius:9px;overflow:hidden}
.path-grid button{background:var(--card);border:0;border-radius:0;padding:24px 18px;text-align:left}.path-grid button:hover{background:var(--mint);color:var(--ink)}.path-grid button[aria-pressed=true]{background:var(--green);color:white}.path-grid button[aria-pressed=true] .circle{color:#f2c9aa}.path-grid strong{display:block;font-family:Georgia,serif;font-size:22px;font-weight:400;margin:8px 0}.path-grid p{font-size:14px}.path-grid .circle{font:24px Georgia;color:var(--orange)}
.rule{border-top:1px solid var(--line);padding-top:26px}.overview-detail{background:var(--mint);padding:25px;margin-top:16px;border-radius:8px}.overview-detail p{margin:12px 0}
.progress-track{height:5px;background:var(--line);border-radius:5px;overflow:hidden;margin:9px 0 20px}.progress-fill{height:100%;background:var(--green);transition:width .2s}.source-box{font-size:13px;color:var(--muted);border-top:1px solid var(--line);padding-top:18px;margin-top:36px}
.lesson-title{margin:8px 0 14px}.gallery{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;margin-top:24px}.gallery.single{grid-template-columns:1fr;max-width:850px}.gallery figure{margin:0;min-width:0}.image-button{border:0;padding:0;width:100%;display:block;background:#000;border-radius:4px;overflow:hidden}.image-button img{display:block;width:100%;height:auto}.gallery figcaption{font-size:12px;margin-top:6px;color:var(--muted)}
.study{display:grid;grid-template-columns:minmax(0,1fr) 235px;gap:32px;margin-top:30px}.tabs{display:flex;flex-wrap:wrap;gap:6px;border-bottom:1px solid var(--line);padding-bottom:12px;margin-bottom:22px}.tabs button{font-size:14px}.reading{max-width:800px;font-size:17px}.reading h3{margin-bottom:16px}.reading p{line-height:1.85}.study-aside{border-left:1px solid var(--line);padding-left:24px;font-size:14px}.study-aside textarea{width:100%;resize:vertical;min-height:125px;background:var(--card);border:1px solid var(--line);border-radius:6px;padding:12px;font-size:14px}.study-aside label{display:block;font-weight:600;margin-bottom:10px}.study-aside .note-status{font-size:12px;margin-top:5px;color:var(--muted)}.reading .step{margin-top:22px}
.quiz-options{display:grid;gap:10px;margin:20px 0}.quiz-options button{text-align:left;background:var(--card);font-size:16px;padding:14px 18px}.quiz-options button[aria-pressed=true]{background:var(--mint);border:2px solid var(--green);color:var(--ink)}
.feedback{border-left:4px solid var(--orange);padding:16px 20px;background:var(--soft);margin-top:20px}.feedback.correct{background:var(--mint);border-color:var(--green)}.feedback strong{display:block;margin-bottom:8px}.bottom-nav{border-top:1px solid var(--line);padding-top:24px;margin-top:38px}
.problem-layout{display:grid;grid-template-columns:310px minmax(0,1fr);gap:30px;margin-top:26px}.problem-nav{display:grid;gap:7px}.problem-nav button{text-align:left;display:flex;gap:12px}.problem-nav b{color:var(--orange)}.problem-nav button[aria-pressed=true] b{color:white}.problem-card{background:var(--card);border:1px solid var(--line);padding:30px;border-radius:9px;align-self:start}.problem-card h2{font-size:30px;margin:10px 0 22px}.problem-card p{font-size:18px;line-height:1.8}.prompt{margin-top:26px;padding-top:20px;border-top:1px solid var(--line)}
.timeline{display:flex;flex-wrap:wrap;gap:8px;margin:26px 0}.timeline button{flex:1;min-width:120px;text-align:left}.timeline button strong{display:block}.timeline-detail{display:grid;grid-template-columns:140px 1fr;gap:28px;background:var(--mint);padding:32px;border-radius:8px}.year{font:32px Georgia;color:var(--green)}.timeline-detail h3{margin-bottom:10px}.timeline-detail p{max-width:750px}.termgrid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:24px}.termgrid details{padding:18px;background:var(--card);border:1px solid var(--line);border-radius:8px}.termgrid summary{cursor:pointer;font-weight:600}.termgrid p{margin-top:12px}
dialog{width:min(1300px,96vw);max-height:95vh;border:0;padding:18px;background:var(--paper);border-radius:10px;color:var(--ink)}dialog::backdrop{background:#081b19dc}dialog img{display:block;width:100%;height:auto;margin-top:14px}dialog .zoom-container{overflow:auto;max-height:75vh}dialog .zoom-container.zoomed img{width:1440px;max-width:none}
#menu-toggle{display:none}#live{position:absolute;left:-10000px;width:1px;height:1px;overflow:hidden}
@media(min-width:1250px){.gallery img{max-height:310px;object-fit:contain}.gallery.single img{max-height:430px}}
@media(max-width:1100px){.shell{grid-template-columns:200px 1fr}.study{grid-template-columns:1fr}.study-aside{border-left:0;border-top:1px solid var(--line);padding:22px 0 0}.hero{gap:24px}.path-grid{grid-template-columns:repeat(2,1fr)}.problem-layout{grid-template-columns:230px 1fr}}
@media(max-width:760px){header{padding:12px 18px}.shell{display:block}aside{display:none;position:static;height:auto;border-right:0;border-bottom:1px solid var(--line)}aside.open{display:block}#menu-toggle{display:inline-block}header .small{display:none}main{padding:24px 18px 40px}.hero{grid-template-columns:1fr;margin-top:0}.hero h1{max-width:600px}.hero img{max-height:310px;object-fit:cover}.gallery{grid-template-columns:1fr}.study{gap:20px}.problem-layout{grid-template-columns:1fr}.problem-nav{grid-template-columns:1fr 1fr}.problem-nav button{font-size:13px}.problem-card{padding:22px}.timeline-detail{grid-template-columns:1fr;gap:12px}.termgrid{grid-template-columns:1fr}h1{letter-spacing:-1px}.reading{font-size:16px}.bottom-nav{gap:14px}.path-grid button{padding:18px 14px}.path-grid strong{font-size:20px}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

html{scroll-padding-top:100px}
main:focus{outline:none}
.breadcrumbs{max-width:1580px;margin:auto;padding:14px 26px;display:flex;flex-wrap:wrap;gap:8px;font-size:13px;border-bottom:1px solid var(--line)}
.breadcrumbs a{text-underline-offset:3px}
header{padding-top:max(12px,env(safe-area-inset-top));min-height:72px}
#menu-backdrop{position:fixed;inset:72px 0 0;z-index:6;background:#102e2580;border:0;border-radius:0}
button{min-height:44px}
.study-aside textarea{font-size:16px}
.bottom-nav{background:var(--paper);padding-bottom:max(14px,env(safe-area-inset-bottom))}
.zoom-container{touch-action:pan-x pan-y pinch-zoom}
dialog{max-height:94dvh;overscroll-behavior:contain}
aside{overscroll-behavior:contain}
.image-button img{aspect-ratio:16/9;object-fit:contain}
@media(max-width:1100px){
 .shell{display:block}
 aside{display:none;position:fixed;top:72px;bottom:0;left:0;z-index:7;width:min(360px,86vw);height:calc(100dvh - 72px);overflow-y:auto;background:var(--paper);border-right:1px solid var(--line);padding-bottom:40px}
 aside.open{display:block}
 #menu-toggle{display:inline-block}
 body.menu-open{overflow:hidden}
 header .small{display:none}
 .study{grid-template-columns:1fr}
 main{padding:28px 32px 40px}
 .hero{grid-template-columns:1fr 1fr}
 .gallery img{max-height:none}
 .bottom-nav{position:sticky;bottom:0;z-index:3}
}
@media(max-width:600px){
 header{gap:8px;padding-left:16px;padding-right:16px;min-height:72px}
 header .row{gap:6px;flex-wrap:nowrap}
 header button{font-size:13px;padding:9px 10px}
 header .brand{font-size:23px;padding:0;white-space:nowrap}
 #menu-toggle{max-width:108px}
 .breadcrumbs{padding:12px 18px;font-size:12px}
 main{padding:24px 18px 28px}
 .hero{grid-template-columns:1fr}
 .gallery{gap:22px}
 .bottom-nav{display:grid;grid-template-columns:1fr 1fr;gap:9px}
 #complete{grid-column:1/-1;grid-row:1}
 .tabs{display:grid;grid-template-columns:repeat(3,1fr);gap:5px}
 .tabs button{font-size:13px;padding:10px 5px}
 .problem-nav{grid-template-columns:1fr}
 .timeline{display:grid;grid-template-columns:1fr 1fr}
 .timeline button{min-width:0}
 .reading p{line-height:1.8}
 .study-aside textarea{min-height:130px}
 .hero h1{font-size:40px}
}
@media(min-width:601px) and (max-width:900px){.gallery{grid-template-columns:1fr}.gallery img{max-height:420px;object-fit:contain}.hero h1{font-size:44px}}