.lesson-hero{position:relative;padding-top:88px;padding-bottom:48px;background:var(--carbon-90);overflow:hidden}.lesson-hero:before{content:"";position:absolute;inset:0;background:radial-gradient(ellipse at 30% 50%,rgba(11,61,145,.08) 0%,transparent 60%),radial-gradient(ellipse at 70% 80%,rgba(252,61,33,.04) 0%,transparent 50%);pointer-events:none}.lesson-hero-inner{position:relative;z-index:1;max-width:820px}.lesson-title{margin-bottom:12px;color:var(--text);font-size:clamp(40px,6vw,80px);font-weight:400;line-height:.92;text-transform:uppercase}.lesson-subtitle{max-width:620px;margin-bottom:28px;color:var(--body);font-size:18px;line-height:1.56}.lesson-meta{display:flex;align-items:center;flex-wrap:wrap;gap:18px;margin-bottom:6px}.lesson-meta-item{display:inline-flex;align-items:center;gap:6px;color:var(--muted);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.lesson-meta-item svg{width:14px;height:14px;opacity:.7}.lesson-meta-divider{width:1px;height:14px;background:var(--line)}.difficulty-badge{display:inline-flex;align-items:center;gap:10px;padding:8px 16px 8px 12px;border:1px solid rgba(255,255,255,.1);background:#111114d9;backdrop-filter:blur(12px)}.difficulty-bar{display:flex;gap:4px}.difficulty-dot{width:7px;height:7px;border-radius:50%;background:var(--faint);transition:background-color .3s ease}.difficulty-dot.is-filled{background:var(--accent)}.difficulty-badge[data-level="1"] .difficulty-dot.is-filled{background:var(--green)}.difficulty-badge[data-level="1"] .difficulty-label{color:var(--green)}.difficulty-badge[data-level="2"] .difficulty-dot.is-filled{background:var(--cyan-pulse)}.difficulty-badge[data-level="2"] .difficulty-label{color:var(--cyan-pulse)}.difficulty-badge[data-level="3"] .difficulty-dot.is-filled{background:var(--gold)}.difficulty-badge[data-level="3"] .difficulty-label{color:var(--gold)}.difficulty-badge[data-level="4"] .difficulty-dot.is-filled{background:var(--heritage)}.difficulty-badge[data-level="4"] .difficulty-label{color:var(--heritage)}.difficulty-badge[data-level="5"] .difficulty-dot.is-filled{background:var(--tech)}.difficulty-badge[data-level="5"] .difficulty-label{color:var(--tech)}.difficulty-label{color:var(--text);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.lesson-section{padding:72px 0;border-top:1px solid var(--line)}.lesson-section:nth-of-type(2n){background:linear-gradient(180deg,#0a0c14 0%,transparent 100%)}.lesson-section:first-of-type{border-top:0}.lesson-section-number{display:inline-flex;align-items:center;justify-content:center;width:32px;height:32px;margin-bottom:18px;border:1px solid rgba(252,61,33,.3);background:#fc3d210f;color:var(--nasa-red);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.lesson-section-title{margin-bottom:22px;padding-left:14px;border-left:2px solid rgba(40,139,255,.35);color:var(--text);font-size:clamp(27px,3.2vw,40px);font-weight:400;line-height:1.15;text-transform:uppercase}.lesson-section-body{max-width:700px}.lesson-section-body p{margin-bottom:20px;color:var(--body);font-size:16px;line-height:1.75}.lesson-section-body p:last-child{margin-bottom:0}.lesson-callout{margin:28px 0;padding:20px 24px;border-left:3px solid rgba(40,139,255,.5);background:#0b3d9112;color:var(--body);font-size:16px;line-height:1.75}.lesson-scene-wrap{margin:36px 0 12px}.lesson-scene{position:relative;overflow:hidden;aspect-ratio:16 / 9;border:1px solid var(--line-strong);background:radial-gradient(ellipse at 30% 20%,#3456a8,#182a5e 52%,#0a1327);box-shadow:0 0 0 1px #288bff2e,0 8px 40px #0b3d9126}.lesson-scene canvas{width:100%!important;height:100%!important;display:block}.lesson-scene-label{position:absolute;top:14px;left:16px;z-index:2;display:inline-flex;align-items:center;gap:8px;padding:6px 12px;border:1px solid rgba(252,61,33,.25);background:#000c;color:var(--carbon-20);font-size:10px;font-weight:500;letter-spacing:.96px;text-transform:uppercase;pointer-events:none;backdrop-filter:blur(8px)}.lesson-scene-label .live-dot{width:5px;height:5px;background:var(--nasa-red)}.lesson-scene-controls{display:flex;align-items:center;gap:8px;margin-top:10px;flex-wrap:wrap}.scene-btn{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:0 18px;border:1px solid rgba(255,255,255,.08);background:#111114b3;backdrop-filter:blur(8px);color:var(--carbon-20);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase;cursor:pointer;transition:border-color .25s ease,color .25s ease,background-color .25s ease,box-shadow .25s ease}.lesson-nav-link{display:inline-flex;align-items:center;justify-content:center;min-height:40px;padding:0 18px;border:1px solid var(--line-strong);background:var(--surface);color:var(--carbon-20);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase;cursor:pointer;transition:border-color .25s ease,color .25s ease,background-color .25s ease,box-shadow .25s ease}.scene-btn:hover{border-color:#288bff80;background:#111114d1;color:#fff}.lesson-nav-link:hover{border-color:var(--accent);background:var(--panel);color:var(--text)}.scene-btn.is-active{border-color:#288bff;background:#0b3d9140;color:#fff;box-shadow:0 0 12px #288bff33}.page-lessons #scene-sun.lesson-scene,.page-lessons #scene-photovoltaic.lesson-scene,.page-lessons #scene-cell-layers.lesson-scene,.page-lessons #scene-scale.lesson-scene,.page-lessons #scene-tracking.lesson-scene,.page-lessons #scene-iss.lesson-scene,.page-lessons #scene-efficiency.lesson-scene{box-shadow:0 0 0 1px #f0a5002e,0 8px 40px #ba75171f}.page-lessons [data-cell-btn].scene-btn.is-active{border-color:#f0a500;background:#ba751733;box-shadow:0 0 12px #f0a5002e}.lesson-scene-caption{margin-top:10px;color:var(--muted);font-size:12px;font-weight:500;letter-spacing:.96px;line-height:1.6;text-transform:uppercase}.lesson-takeaways,.lesson-homework{padding:72px 0;border-top:1px solid var(--line)}.takeaway-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:16px;margin-top:32px}.takeaway-card{position:relative;padding:28px 24px;border:1px solid var(--line);border-top:2px solid var(--nasa-blue-light);background:var(--panel);transition:border-color .3s ease,background-color .3s ease,transform .3s ease}.takeaway-card:hover{border-color:var(--line-strong);background:#1c1c20;transform:translateY(-2px)}.takeaway-icon{display:inline-flex;align-items:center;justify-content:center;width:40px;height:40px;margin-bottom:14px;border:1px solid rgba(40,139,255,.2);background:#0b3d9126;color:var(--nasa-blue-light);font-size:1.1rem}.takeaway-card h4{margin-bottom:8px;color:var(--text);font-size:27px;font-weight:400;line-height:1.37;text-transform:uppercase}.takeaway-card p{color:var(--body);font-size:16px;line-height:1.5}.homework-grid{display:grid;gap:14px;margin-top:32px;counter-reset:homework}.homework-card{position:relative;display:grid;grid-template-columns:54px 1fr;overflow:hidden;border:1px solid var(--line);background:var(--panel);transition:border-color .3s ease,background-color .3s ease,transform .3s ease;counter-increment:homework}.homework-card:hover{border-color:var(--line-strong);background:#1c1c20;transform:translate(4px)}.homework-number{display:flex;align-items:flex-start;justify-content:center;padding-top:26px;background:var(--carbon-90);border-right:1px solid var(--line);color:var(--carbon-40);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.homework-body{padding:22px 24px}.homework-type{display:inline-flex;align-items:center;gap:6px;margin-bottom:8px;font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.homework-type.type-observe{color:var(--green)}.homework-type.type-explore{color:var(--cyan-pulse)}.homework-type.type-think{color:var(--gold)}.homework-type.type-research{color:var(--heritage)}.homework-type.type-create{color:var(--tech)}.homework-card h4{margin-bottom:8px;color:var(--text);font-size:27px;font-weight:400;line-height:1.37;text-transform:uppercase}.homework-card p{color:var(--body);font-size:16px;line-height:1.5}.lesson-bottom-nav{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:48px 0 24px;border-top:1px solid var(--line);flex-wrap:wrap}.filter-bar{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin-bottom:36px}.filter-select{appearance:none;-webkit-appearance:none;min-height:40px;width:auto;padding:0 36px 0 14px;border:1px solid var(--line-strong);background:var(--surface) url("data:image/svg+xml,%3Csvg width='10' height='6' viewBox='0 0 10 6' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1L5 5L9 1' stroke='%23969696' stroke-width='1.2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") right 12px center no-repeat;color:var(--text);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase;cursor:pointer;transition:border-color .3s ease,color .3s ease,background-color .3s ease}.filter-select:hover,.filter-select:focus{border-color:var(--accent);background-color:var(--panel);color:var(--text);outline:none}.filter-select option{background:var(--surface);color:var(--text)}.filter-count{margin-left:auto;color:var(--muted);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.lesson-listing-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(340px,1fr));gap:18px}.lesson-listing-card{display:flex;flex-direction:column;padding:32px 28px;border:1px solid var(--line);border-left:3px solid var(--nasa-blue-light);background:var(--panel);text-decoration:none;color:inherit;transition:border-color .3s ease,background-color .3s ease,transform .3s ease,box-shadow .3s ease}.lesson-listing-card:hover{border-color:var(--line-strong);border-left-color:var(--nasa-red);background:#1c1c20;transform:translateY(-3px);box-shadow:0 8px 24px #0006}.lesson-listing-card .difficulty-badge{margin-bottom:16px;align-self:flex-start}.lesson-listing-card h3{margin-bottom:8px;color:var(--text);font-size:27px;font-weight:400;line-height:1.37;text-transform:uppercase}.lesson-listing-card .listing-desc{flex:1;margin-bottom:18px;color:var(--body);font-size:16px;line-height:1.5}.lesson-listing-card .listing-meta{display:flex;align-items:center;gap:14px;color:var(--muted);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}.listing-empty{grid-column:1 / -1;padding:60px 0;text-align:center;color:var(--muted);font-size:12px;font-weight:500;letter-spacing:.96px;text-transform:uppercase}@media(max-width:900px){.lesson-scene{aspect-ratio:4 / 3}.takeaway-grid{grid-template-columns:1fr}}@media(max-width:767px){.lesson-hero{padding-top:72px;padding-bottom:36px}.lesson-title{font-size:40px}.lesson-section,.lesson-takeaways,.lesson-homework{padding:48px 0}.lesson-scene{aspect-ratio:1 / 1}.homework-card{grid-template-columns:1fr}.homework-number{display:none}.lesson-meta{gap:10px}.lesson-meta-divider{display:none}.lesson-bottom-nav{flex-direction:column;align-items:stretch}.lesson-nav-link{justify-content:center}.lesson-listing-grid{grid-template-columns:1fr}.filter-bar{flex-direction:column;align-items:stretch}.filter-select{width:100%}.filter-count{margin-left:0}}