.lesson-page{background:radial-gradient(circle at 90% 20rem,var(--color-cosmic-glow),#0000 30rem),var(--color-canvas);color:var(--color-text);font-family:var(--font-body);min-height:100vh}.lesson-page *,.lesson-page :after,.lesson-page :before{box-sizing:border-box}.lesson-page-main{margin:0 auto;padding:var(--space-6) 0 var(--space-section);width:min(100% - (2 * var(--page-gutter)),var(--content-wide))}.lesson-page-hero{background:var(--color-surface-inverse);border:1px solid var(--color-border-inverse);border-radius:var(--radius-xl);box-shadow:var(--shadow-card);color:var(--color-text-inverse);display:flex;flex-direction:column;gap:var(--space-7);isolation:isolate;justify-content:space-between;min-height:39rem;overflow:hidden;padding:clamp(2rem,6vw,5.5rem);position:relative}.lesson-page-hero:after{aspect-ratio:1;border:1px solid var(--color-cosmic-line-strong);border-radius:50%;box-shadow:0 0 0 4rem var(--color-cosmic-glow),0 0 0 9rem color-mix(in srgb,var(--color-brand) 4%,#0000);content:"";position:absolute;right:clamp(-17rem,-8vw,-4rem);top:48%;translate:0 -50%;width:clamp(22rem,38vw,38rem);z-index:-1}.lesson-page-hero__top{align-items:center;display:flex;gap:var(--space-5);justify-content:space-between}.lesson-page-back{align-items:center;color:var(--color-text-inverse-muted);display:inline-flex;font-size:var(--text-sm);font-weight:800;gap:var(--space-2);text-decoration:none}.lesson-page-count{color:var(--color-accent-soft);font-family:var(--font-mono);letter-spacing:.14em}.lesson-page-count,.lesson-page-eyebrow{font-size:var(--text-xs);font-weight:800}.lesson-page-eyebrow{color:var(--color-brand);letter-spacing:.18em;margin:0;text-transform:uppercase}.lesson-page-hero .lesson-page-eyebrow{color:var(--color-accent-soft)}.lesson-page-hero__body{grid-gap:var(--space-7);align-items:end;display:grid;gap:var(--space-7);grid-template-columns:minmax(0,1fr) 12rem}.lesson-page-hero h1{color:var(--color-text-inverse);font-family:var(--font-display);font-size:clamp(4rem,7.5vw,8rem);font-weight:400;letter-spacing:-.07em;line-height:.88;margin:var(--space-4) 0 var(--space-5);max-width:65rem}.lesson-page-hero__body>div>p:last-child{color:var(--color-text-inverse-muted);font-size:clamp(1rem,1.35vw,1.2rem);line-height:1.7;margin:0;max-width:47rem}.lesson-page-hero__mark{aspect-ratio:1;background:var(--color-cosmic-center);border:1px solid var(--color-cosmic-line-strong);border-radius:50%;color:var(--color-accent-soft);display:grid;place-content:center;text-align:center;width:11rem}.lesson-page-hero__mark span{font-family:var(--font-display);font-size:4rem;line-height:1}.lesson-page-hero__mark small{color:var(--color-text-inverse-muted);font-size:.62rem;font-weight:800;letter-spacing:.16em;margin-top:var(--space-2);text-transform:uppercase}.lesson-page-objectives{border-left:1px solid var(--color-border-inverse);border-top:1px solid var(--color-border-inverse);display:grid;grid-template-columns:repeat(3,minmax(0,1fr))}.lesson-page-objectives div{border-bottom:1px solid var(--color-border-inverse);border-right:1px solid var(--color-border-inverse);min-height:7rem;padding:var(--space-4)}.lesson-page-objectives span{color:var(--color-accent-soft);font-family:var(--font-mono);font-size:var(--text-xs);font-weight:800}.lesson-page-objectives p{color:var(--color-text-inverse-muted);line-height:1.5;margin:var(--space-4) 0 0}.lesson-page-layout{grid-gap:var(--space-5);align-items:start;display:grid;gap:var(--space-5);grid-template-columns:minmax(14rem,.28fr) minmax(0,1fr);margin-top:var(--space-5)}.lesson-page-contents{background:var(--color-surface-raised);border:1px solid var(--color-border);border-radius:var(--radius-xl);box-shadow:var(--shadow-sm);padding:var(--space-5);position:sticky;top:9rem}.lesson-page-contents>p{color:var(--color-brand);font-size:var(--text-xs);font-weight:800;letter-spacing:.14em;margin:0 0 var(--space-4);text-transform:uppercase}.lesson-page-contents nav{border-top:1px solid var(--color-border);display:grid}.lesson-page-contents nav a{grid-gap:var(--space-2);border-bottom:1px solid var(--color-border);color:var(--color-text-muted);display:grid;font-size:var(--text-sm);font-weight:700;gap:var(--space-2);grid-template-columns:2rem 1fr;line-height:1.35;padding:var(--space-3) 0;text-decoration:none}.lesson-page-contents nav a span{color:var(--color-brand);font-family:var(--font-mono);font-size:var(--text-xs)}.lesson-page-contents>button{align-items:center;background:#0000;border:1px solid var(--color-border-strong);border-radius:var(--radius-pill);color:var(--color-text-muted);cursor:pointer;display:flex;font:inherit;font-size:var(--text-sm);font-weight:800;gap:var(--space-2);justify-content:center;margin-top:var(--space-5);min-height:3rem;padding:.7rem 1rem;width:100%}.lesson-page-contents>button[aria-pressed=true]{border-color:color-mix(in srgb,var(--color-success) 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var(--color-border);list-style:none;margin:var(--space-5) 0 0;max-width:54rem;padding:0}.lesson-page-article section>ul li{border-bottom:1px solid var(--color-border);color:var(--color-text-muted);line-height:1.55;padding:var(--space-3) var(--space-3) var(--space-3) 1.7rem;position:relative}.lesson-page-article section>ul li:before{color:var(--color-brand);content:"·";font-weight:900;left:.45rem;position:absolute}.lesson-page-groups{border-left:1px solid var(--color-border-strong);border-top:1px solid var(--color-border-strong);display:grid;grid-template-columns:repeat(2,minmax(0,1fr));margin-top:var(--space-6)}.lesson-page-groups>div{border-bottom:1px solid var(--color-border-strong);border-right:1px solid var(--color-border-strong);min-height:10rem;padding:var(--space-4)}.lesson-page-groups span{color:var(--color-brand);display:block;font-family:var(--font-display);font-size:1.45rem}.lesson-page-groups strong{color:var(--color-text);display:block;margin-top:var(--space-4)}.lesson-page-groups p{color:var(--color-text-muted);line-height:1.55;margin:var(--space-2) 0 0}.lesson-page-inline-link{align-items:center;background:var(--color-brand);border-radius:var(--radius-pill);color:var(--color-on-brand);display:inline-flex;font-size:var(--text-sm);font-weight:800;gap:var(--space-6);justify-content:space-between;margin-top:var(--space-5);min-height:3rem;padding:.7rem 1rem;text-decoration:none}.lesson-page-article>.lesson-page-practice{background:var(--color-surface-inverse);border:1px solid var(--color-border-inverse);border-radius:var(--radius-lg);color:var(--color-text-inverse);margin:0;padding:clamp(1.5rem,4vw,3rem)}.lesson-page-practice .lesson-page-eyebrow{color:var(--color-accent-soft)}.lesson-page-practice h2{color:var(--color-text-inverse)}.lesson-page-practice>p{color:var(--color-text-inverse-muted)!important}.lesson-page-practice>a{align-items:center;background:var(--color-brand);border-radius:var(--radius-pill);color:var(--color-on-brand);display:inline-flex;font-size:var(--text-sm);font-weight:800;gap:var(--space-6);justify-content:space-between;margin-top:var(--space-4);min-height:3rem;padding:.7rem 1rem;text-decoration:none}.lesson-page-navigation{grid-gap:var(--space-5);display:grid;gap:var(--space-5);grid-template-columns:1fr 1fr;margin-top:var(--space-5)}.lesson-page-navigation>a{background:var(--color-surface-raised);border:1px solid var(--color-border);border-radius:var(--radius-lg);color:var(--color-text);display:flex;flex-direction:column;justify-content:space-between;min-height:9rem;padding:var(--space-5);text-decoration:none}.lesson-page-navigation>a:last-child{text-align:right}.lesson-page-navigation small{color:var(--color-text-subtle);font-size:var(--text-xs);font-weight:800;letter-spacing:.12em;text-transform:uppercase}.lesson-page-navigation strong{align-items:center;color:var(--color-brand);display:flex;font-family:var(--font-display);font-size:clamp(1.4rem,2.5vw,2rem);font-weight:400;gap:var(--space-4);justify-content:space-between}.lesson-not-found{background:var(--color-surface-raised);border:1px solid var(--color-border);border-radius:var(--radius-xl);display:flex;flex-direction:column;justify-content:center;margin:var(--space-6) auto;min-height:32rem;padding:clamp(2rem,6vw,5rem);width:min(100% - (2 * var(--page-gutter)),70rem)}.lesson-not-found h1{color:var(--color-text);font-family:var(--font-display);font-size:clamp(3.4rem,7vw,7rem);font-weight:400;letter-spacing:-.06em;line-height:.9;margin:var(--space-3) 0}.lesson-not-found>p:not(.lesson-page-eyebrow){color:var(--color-text-muted);line-height:1.7}.lesson-not-found a{background:var(--color-brand);border-radius:var(--radius-pill);color:var(--color-on-brand);font-weight:800;margin-top:var(--space-4);padding:.75rem 1.1rem;text-decoration:none;width:fit-content}.lesson-page a:focus-visible,.lesson-page button:focus-visible{outline:3px solid var(--color-focus);outline-offset:3px}@media (hover:hover){.lesson-page-contents nav a:hover{color:var(--color-brand)}.lesson-page-inline-link:hover,.lesson-page-practice>a:hover{filter:brightness(1.08)}.lesson-page-navigation>a:hover{border-color:var(--color-brand)}}@media (max-width:900px){.lesson-page-layout{grid-template-columns:1fr}.lesson-page-contents{position:static}.lesson-page-contents nav{grid-template-columns:1fr 1fr}.lesson-page-contents nav a:nth-child(odd){border-right:1px solid var(--color-border);padding-right:var(--space-3)}}@media (max-width:700px){.lesson-page-main{padding-top:.75rem;width:min(100% - 1rem,var(--content-wide))}.lesson-page-hero{border-radius:var(--radius-lg);min-height:auto;padding:1.5rem}.lesson-page-hero__body{grid-template-columns:1fr}.lesson-page-hero h1{font-size:clamp(3.5rem,16.5vw,5.3rem)}.lesson-page-hero__mark{opacity:.3;position:absolute;right:-4rem;top:7rem;width:11rem;z-index:-1}.lesson-page-objectives{grid-template-columns:1fr}.lesson-page-objectives div{min-height:auto}.lesson-page-objectives p{margin-top:var(--space-2)}.lesson-page-article,.lesson-page-contents{border-radius:var(--radius-lg);padding:1.5rem}.lesson-page-contents nav{grid-template-columns:1fr}.lesson-page-contents nav a:nth-child(odd){border-right:0;padding-right:0}.lesson-page-article h2{font-size:clamp(2.7rem,14vw,4.3rem)}.lesson-page-groups,.lesson-page-navigation{grid-template-columns:1fr}.lesson-page-navigation>span{display:none}.lesson-page-navigation>a:last-child{text-align:left}}