.lesson-hero.svelte-umvp4x{isolation:isolate;border-radius:var(--ds-radius-hero);width:100%;color:var(--ds-on-dark);background:var(--ds-hero-fill);font-family:var(--ds-font-ui);position:relative;overflow:clip}.lesson-hero.svelte-umvp4x:after{z-index:-1;border-radius:inherit;content:"";opacity:.35;pointer-events:none;background-image:radial-gradient(oklch(100% 0 0/.14) 1px,#0000 1px);background-size:22px 22px;position:absolute;inset:0;-webkit-mask-image:linear-gradient(115deg,oklch(0% 0 0) 30%,#0000 75%);mask-image:linear-gradient(115deg,oklch(0% 0 0) 30%,#0000 75%)}.hero-decoration.svelte-umvp4x{z-index:-1;border-radius:inherit;pointer-events:none;position:absolute;inset:0;overflow:hidden}.hero-blob.svelte-umvp4x{z-index:-1;pointer-events:none;border-radius:50%;position:absolute}.blob-one.svelte-umvp4x{background:oklch(100% 0 0/.1);width:420px;height:420px;top:-180px;right:-140px}.blob-two.svelte-umvp4x{background:color-mix(in srgb, var(--ds-glow) 15%, transparent);width:360px;height:360px;bottom:-200px;right:120px}.blob-three.svelte-umvp4x{background:oklch(100% 0 0/.07);width:300px;height:300px;bottom:-160px;left:-100px}.hero-top.svelte-umvp4x{z-index:1;align-items:center;padding:12px 24px 0;display:flex;position:relative}.hero-back.svelte-umvp4x{align-items:center;gap:var(--ds-space-2);border-radius:var(--ds-radius-pill);max-width:100%;min-height:44px;color:var(--ds-on-dark);transition:background-color var(--vt-nav-transition), color var(--vt-nav-transition);background:0 0;margin-left:-8px;padding:0 12px;font-size:.875rem;font-weight:600;line-height:1.35;text-decoration:none;display:inline-flex}.hero-back.svelte-umvp4x:active{background:var(--ds-on-dark-line)}.hero-back.svelte-umvp4x:focus-visible{outline:2px solid var(--vt-nav-focus-ring);outline-offset:3px}@media (hover:hover) and (pointer:fine){.hero-back.svelte-umvp4x:hover{background:var(--vt-nav-on-dark-hover-bg);color:var(--vt-nav-on-dark-hover-fg)}}.hero-body.svelte-umvp4x{grid-template-columns:minmax(0,1fr);align-items:center;gap:20px;padding:12px 28px 20px;display:grid;position:relative}.has-subject-art.svelte-umvp4x .hero-body:where(.svelte-umvp4x){grid-template-columns:minmax(0,1fr) 160px}.hero-copy.svelte-umvp4x{z-index:1;min-width:0;position:relative}.hero-eyebrow.svelte-umvp4x{letter-spacing:.15em;text-transform:uppercase;color:var(--ds-glow);align-items:center;gap:10px;font-size:10px;font-weight:700;display:flex}.hero-eyebrow.svelte-umvp4x:before{content:"";background:var(--ds-glow);border-radius:2px;flex-shrink:0;width:22px;height:3px}.hero-title.svelte-umvp4x{color:var(--ds-on-dark);letter-spacing:-.045em;text-wrap:balance;overflow-wrap:break-word;max-width:900px;margin:10px 0 0;font-size:clamp(26px,2.2vw,34px);font-weight:800;line-height:1.1}.long-title.svelte-umvp4x .hero-title:where(.svelte-umvp4x){font-size:clamp(24px,2vw,30px)}.hero-description.svelte-umvp4x{max-width:540px;color:var(--ds-on-dark);margin-top:12px;font-size:15px;line-height:1.5}.hero-actions.svelte-umvp4x{flex-wrap:wrap;align-items:center;gap:16px;margin-top:14px;display:flex}.lesson-begin{background:var(--ds-white);min-height:44px;color:var(--ds-dark);border-radius:var(--ds-radius-small);padding:0 20px;font-size:13px;font-weight:700}.lesson-begin:hover{background:var(--ds-pearl)}.hero-reading.svelte-umvp4x{color:var(--ds-on-dark);align-items:center;gap:7px;font-size:12px;font-weight:500;display:flex}.hero-meta.svelte-umvp4x{z-index:1;border-top:1px solid var(--ds-on-dark-line);background:color-mix(in srgb, var(--ds-dark) 22%, transparent);flex-wrap:wrap;align-items:center;gap:20px;padding:12px 28px;display:flex;position:relative}.hero-meta.svelte-umvp4x span:where(.svelte-umvp4x){color:var(--ds-on-dark);align-items:center;gap:8px;font-size:12px;font-weight:500;display:inline-flex}.hero-meta.svelte-umvp4x svg{width:15px;height:15px;color:var(--ds-glow)}.hero-meta.svelte-umvp4x .meta-intro:where(.svelte-umvp4x){letter-spacing:.13em;text-transform:uppercase;margin-right:auto;font-size:10px;font-weight:700}@media (width<=900px){.hero-top.svelte-umvp4x{padding:12px 24px 0}.hero-body.svelte-umvp4x{gap:8px;padding:12px 24px 20px}.hero-meta.svelte-umvp4x{gap:16px;padding:12px 24px}}@media (width<=640px){.has-subject-art.svelte-umvp4x .hero-body:where(.svelte-umvp4x){grid-template-columns:1fr;padding-top:8px}.hero-top.svelte-umvp4x{padding:8px 16px 0}.hero-body.svelte-umvp4x{row-gap:0;padding:8px 16px 12px}.hero-title.svelte-umvp4x{font-size:28px}.medium-title.svelte-umvp4x .hero-title:where(.svelte-umvp4x){font-size:clamp(24px,6.7vw,30px)}.long-title.svelte-umvp4x .hero-title:where(.svelte-umvp4x){font-size:clamp(24px,6.7vw,28px);line-height:1.14}.extra-long-word.svelte-umvp4x .hero-body:where(.svelte-umvp4x){padding-inline:10px}.extra-long-word.svelte-umvp4x .hero-title:where(.svelte-umvp4x){letter-spacing:-.1em;font-size:clamp(24px,6.7vw,26px)}.hero-description.svelte-umvp4x{font-size:14px;line-height:1.55}.hero-actions.svelte-umvp4x{margin-top:12px}.hero-meta.svelte-umvp4x{gap:10px 16px;padding:10px 16px}.hero-meta.svelte-umvp4x .meta-intro:where(.svelte-umvp4x){display:none}}.subject-visual.svelte-p81etp{justify-self:center;width:100%;min-width:0;max-width:160px;margin:0}.subject-visual.svelte-p81etp img:where(.svelte-p81etp){aspect-ratio:3/2;object-fit:contain;border-radius:var(--ds-radius-rich);width:100%;height:auto;display:block}@media (width<=640px){.subject-visual.svelte-p81etp{opacity:.78;pointer-events:none;max-width:44px;position:absolute;top:-38px;right:16px}}.lesson-inline-code.svelte-1a4ylco{background:var(--ds-pearl);color:var(--ds-ink);white-space:break-spaces;overflow-wrap:anywhere;font-weight:600;line-height:1.55}.lesson-rich-strong.svelte-1a4ylco,.lesson-key-term.svelte-1a4ylco{font-weight:750}.lesson-key-term.svelte-1a4ylco{letter-spacing:.002em}.lesson-rich-italic.svelte-1a4ylco{font-style:italic}.lesson-rich-link.svelte-1a4ylco{color:var(--ds-accent);text-decoration-thickness:.08em;-webkit-text-decoration-color:color-mix(in srgb, currentColor 62%, transparent);text-decoration-color:color-mix(in srgb, currentColor 62%, transparent);transition-duration:var(--ds-duration-fast);font-weight:650}.lesson-rich-link.svelte-1a4ylco:focus-visible{outline-color:var(--ds-accent)}.lesson-rich-math{overflow-wrap:anywhere}.lesson-rich-math .katex-display{max-width:100%;padding-block:.125em;overflow:auto hidden}.lesson-rich-math sub,.lesson-rich-math sup{line-height:0}html[data-motion=reduce] .lesson-rich-link.svelte-1a4ylco{transition:none}@media (prefers-reduced-motion:reduce){html:not([data-motion=full]) .lesson-rich-link.svelte-1a4ylco{transition:none}}.lesson-prose.svelte-15wemaz{letter-spacing:-.008em;text-wrap:pretty;color:var(--ds-ink);font-size:1.0625rem;line-height:1.85}.lesson-caption.svelte-15wemaz{color:var(--ds-ink)}.teaching-card.svelte-15wemaz{border-radius:var(--ds-radius-card);background:var(--ds-white);box-shadow:0 12px 30px -26px color-mix(in srgb, var(--ds-ink) 55%, transparent);isolation:isolate;margin-block:1.75rem}.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child,.era-card-header.svelte-15wemaz,.quiz-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child{position:relative;overflow:hidden}.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child:after,.era-card-header.svelte-15wemaz:after,.quiz-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child:after{content:"";pointer-events:none;background:linear-gradient(112deg,#0000 14%,oklch(100% 0 0/.2) 44%,#0000 68%);position:absolute;inset:0}.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child{padding:.95rem 1.5rem}.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child>p:where(.svelte-15wemaz){overflow-wrap:anywhere;min-width:0}.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):nth-child(2){padding:1.25rem 1.5rem 1.5rem;line-height:1.8}.era-card.svelte-15wemaz{border-radius:var(--ds-radius-card);background:var(--ds-white);box-shadow:0 12px 30px -26px color-mix(in srgb, var(--ds-ink) 55%, transparent);transition:transform var(--ds-duration-base) var(--ds-ease), box-shadow var(--ds-duration-base) var(--ds-ease);position:relative}@media (hover:hover) and (pointer:fine){.era-card.svelte-15wemaz:hover{box-shadow:0 18px 36px -26px color-mix(in srgb, var(--ds-ink) 65%, transparent);transform:translateY(-2px)}}.era-card-header.svelte-15wemaz{background:var(--timeline-header-fill);padding:.95rem 1.5rem}.era-card.svelte-15wemaz>div:where(.svelte-15wemaz):last-child{padding:1.25rem 1.5rem 1.45rem;line-height:1.8}.concept-card.svelte-15wemaz{border-radius:var(--ds-radius-tile);background:var(--ds-white);box-shadow:0 10px 24px -24px color-mix(in srgb, var(--ds-ink) 72%, transparent);gap:.8rem;padding:1.5rem;position:relative;overflow:hidden}.concept-card.svelte-15wemaz:before{background:var(--teaching-accent);content:"";width:100%;height:5px;position:absolute;top:0;left:0}.concept-number.svelte-15wemaz{background:color-mix(in srgb, var(--teaching-accent) 16%, var(--ds-white));width:2.25rem;height:2.25rem;color:var(--ds-ink)}.concept-card.svelte-15wemaz>div:where(.svelte-15wemaz){line-height:1.75}.comparison-table.svelte-15wemaz{border-radius:var(--ds-radius-tile);background:var(--ds-white);color:var(--ds-ink);box-shadow:0 12px 30px -26px color-mix(in srgb, var(--ds-ink) 55%, transparent);margin-block:1.75rem}.comparison-table.svelte-15wemaz thead:where(.svelte-15wemaz),.comparison-table.svelte-15wemaz .is-striped:where(.svelte-15wemaz),.comparison-table.svelte-15wemaz .lesson-table-caption:where(.svelte-15wemaz){background:var(--ds-pearl)}.comparison-table.svelte-15wemaz tr:where(.svelte-15wemaz),.comparison-table.svelte-15wemaz th:where(.svelte-15wemaz),.comparison-table.svelte-15wemaz td:where(.svelte-15wemaz),.comparison-table.svelte-15wemaz .lesson-table-caption:where(.svelte-15wemaz){border-color:var(--ds-line)}.comparison-table.svelte-15wemaz th:where(.svelte-15wemaz){padding:1.1rem 1.25rem}.comparison-table.svelte-15wemaz td:where(.svelte-15wemaz){padding:1.15rem 1.25rem;line-height:1.8}@media (width<=40rem){.comparison-table.svelte-15wemaz th:where(.svelte-15wemaz),.comparison-table.svelte-15wemaz td:where(.svelte-15wemaz){padding-inline:.875rem}}.comparison-table.svelte-15wemaz td:where(.svelte-15wemaz) .lesson-rich-math{overflow-wrap:normal}.spectrum-card.svelte-15wemaz{border-radius:var(--ds-radius-tile);background:var(--ds-white);color:var(--ds-ink);box-shadow:0 12px 30px -26px color-mix(in srgb, var(--ds-ink) 55%, transparent);padding:1.5rem}.spectrum-title.svelte-15wemaz{letter-spacing:var(--ds-track-eyebrow);text-transform:uppercase;color:var(--ds-accent);font-size:.75rem}.spectrum-track.svelte-15wemaz{box-shadow:inset 0 1px 2px color-mix(in srgb, var(--ds-ink) 18%, transparent)}.spectrum-track.svelte-15wemaz>div:where(.svelte-15wemaz){position:relative}.spectrum-track.svelte-15wemaz>div:where(.svelte-15wemaz):after{content:"";background:linear-gradient(oklch(100% 0 0/.26),#0000);position:absolute;inset:0}.worked-steps.svelte-15wemaz>li:where(.svelte-15wemaz)+li:where(.svelte-15wemaz){border-top:2px solid var(--ds-line)}.worked-example-card.svelte-15wemaz li:where(.svelte-15wemaz){padding-block:1.1rem}.step-number.svelte-15wemaz{background:var(--teaching-accent);color:var(--ds-on-dark)}.worked-result.svelte-15wemaz{border:2px solid var(--teaching-accent);background:var(--ds-pearl);color:var(--ds-ink)}.key-takeaway-card.svelte-15wemaz,.summary-card.svelte-15wemaz{background:var(--full-card-fill);color:var(--teaching-foreground,var(--ds-on-dark))}.key-takeaway-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child,.summary-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child{align-items:flex-start;color:var(--teaching-foreground,var(--ds-on-dark))!important;background:0 0!important}.key-takeaway-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child:after,.summary-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child:after{background:linear-gradient(112deg,#0000 14%,oklch(100% 0 0/.08) 44%,#0000 68%)}.key-takeaway-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child>span:where(.svelte-15wemaz):first-child{background:oklch(100% 0 0/.2);border-radius:.6rem;flex:none;place-items:center;width:1.9rem;height:1.9rem;display:grid}.key-takeaway-card.svelte-15wemaz>div:where(.svelte-15wemaz):last-child,.summary-card.svelte-15wemaz>div:where(.svelte-15wemaz):last-child{color:var(--teaching-foreground,var(--ds-on-dark))}.key-takeaway-card.svelte-15wemaz a,.summary-card.svelte-15wemaz a,.key-takeaway-card.svelte-15wemaz .lesson-key-term,.key-takeaway-card.svelte-15wemaz .lesson-rich-link,.key-takeaway-card.svelte-15wemaz .lesson-rich-math,.summary-card.svelte-15wemaz .lesson-key-term,.summary-card.svelte-15wemaz .lesson-rich-link,.summary-card.svelte-15wemaz .lesson-rich-math{color:inherit}.quiz-card.svelte-15wemaz{background:var(--ds-white);box-shadow:0 14px 34px -26px color-mix(in srgb, var(--ds-ink) 60%, transparent)}.quiz-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child{padding:.95rem 1.5rem}.quiz-choice.svelte-15wemaz{border:1px solid var(--ds-line);background:var(--ds-white)}.quiz-answer.svelte-15wemaz{border:1px solid var(--ds-line);background:var(--ds-pearl)}.quiz-answer-body.svelte-15wemaz{border-top:1px solid var(--ds-line)}@media (width<=640px){.lesson-prose.svelte-15wemaz{font-size:1rem;line-height:1.8}.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):first-child,.teaching-card.svelte-15wemaz>div:where(.svelte-15wemaz):nth-child(2){padding:1rem}}.lesson-journey.svelte-a7s29f{border:1px solid var(--ds-line);border-radius:calc(var(--ds-radius-card) + .15rem);background:var(--ds-white);width:100%;min-width:0;max-width:17rem;box-shadow:0 .75rem 1.75rem color-mix(in srgb, var(--ds-dark) 5%, transparent);color:var(--ds-ink);padding:1rem}.journey-heading.svelte-a7s29f,.journey-status.svelte-a7s29f{justify-content:space-between;align-items:center;gap:.5rem;display:flex}.journey-heading.svelte-a7s29f>div:where(.svelte-a7s29f){min-width:0}.journey-eyebrow.svelte-a7s29f{font-family:var(--ds-font-ui);text-transform:uppercase;letter-spacing:.14em;color:var(--ds-accent);font-size:.6rem;font-weight:700;display:block}.journey-title.svelte-a7s29f{font-family:var(--ds-font-ui);letter-spacing:-.025em;margin-top:.18rem;font-size:1.025rem;font-weight:700;display:block}.journey-count.svelte-a7s29f{background:var(--ds-pearl);white-space:nowrap;border-radius:999px;flex:none;padding:.27rem .42rem;font-size:.61rem;font-weight:650}.journey-status.svelte-a7s29f{color:var(--ds-ink-muted);margin-top:1rem;font-size:.69rem}.journey-status.svelte-a7s29f strong:where(.svelte-a7s29f){color:var(--ds-ink);font-variant-numeric:tabular-nums;font-size:.67rem;font-weight:700}.journey-progress.svelte-a7s29f{background:var(--ds-pearl);border-radius:1rem;height:.28rem;margin:.45rem 0 .9rem;overflow:hidden}.journey-progress.svelte-a7s29f>span:where(.svelte-a7s29f){background:var(--ds-accent);border-radius:inherit;height:100%;transition:width .2s;display:block}.journey-list.svelte-a7s29f{overscroll-behavior:contain;scrollbar-width:thin;scrollbar-color:var(--ds-line) transparent;flex-direction:column;gap:.14rem;max-height:min(52vh,28rem);display:flex;overflow-y:auto}.vt-lesson-toc-row.svelte-a7s29f{min-height:2.4rem;font-family:var(--ds-font-ui);border-radius:.72rem;align-items:flex-start;gap:.55rem;padding:.5rem .55rem;font-size:.8125rem;line-height:1.45;display:flex}.vt-lesson-toc-row.active.svelte-a7s29f{background:var(--ds-dark);color:var(--ds-on-dark);font-weight:650}.journey-number.svelte-a7s29f{background:var(--ds-pearl);width:1.35rem;height:1.35rem;color:var(--ds-ink-muted);font-variant-numeric:tabular-nums;border-radius:.42rem;flex-shrink:0;justify-content:center;align-items:center;margin-top:.04rem;font-size:.625rem;display:flex}.active.svelte-a7s29f .journey-number:where(.svelte-a7s29f){background:var(--ds-on-dark-pill);color:var(--ds-on-dark)}.journey-label.svelte-a7s29f{overflow-wrap:anywhere;flex:1;min-width:0}.reading-dot.svelte-a7s29f{background:var(--ds-glow);border-radius:50%;flex-shrink:0;width:.3rem;height:.3rem}.journey-footer.svelte-a7s29f{border-top:1px solid var(--ds-line);color:var(--ds-ink-muted);align-items:center;gap:.65rem;margin:.85rem 0 0;padding:.75rem 0 0;font-size:.6875rem;line-height:1.6;display:flex}.footer-mark.svelte-a7s29f{background:var(--ds-pearl);width:1.55rem;height:1.55rem;color:var(--ds-accent);border-radius:.5rem;justify-content:center;align-items:center;font-size:1rem;display:flex}@media (prefers-reduced-motion:reduce){.journey-progress.svelte-a7s29f>span:where(.svelte-a7s29f){transition:none}}.vt-lesson-toc-row.svelte-a7s29f{transition:background-color var(--ds-duration-fast) var(--ds-ease), color var(--ds-duration-fast) var(--ds-ease), border-color var(--ds-duration-fast) var(--ds-ease)}@media (hover:hover) and (pointer:fine){.vt-lesson-toc-row.svelte-a7s29f:not([aria-current]):hover{background:var(--ds-pearl);color:var(--ds-ink)}}.vt-lesson-toc-row.svelte-a7s29f:not([aria-current]):focus-visible{background:var(--ds-pearl);color:var(--ds-ink);outline:2px solid var(--ds-accent);outline-offset:2px}.vt-lesson-toc-row[aria-current].svelte-a7s29f:focus-visible{outline:2px solid var(--ds-accent);outline-offset:2px}@media (width<=52rem){.lesson-journey.svelte-a7s29f{max-width:none;padding:.85rem}.journey-list.svelte-a7s29f{grid-template-columns:repeat(auto-fit,minmax(min(100%,13rem),1fr));gap:.25rem;max-height:min(48vh,22rem);display:grid}.vt-lesson-toc-row.svelte-a7s29f{min-height:2.75rem}}.lesson-reader.svelte-1i4h1k2{font-family:var(--ds-font-ui);color:var(--ds-ink);padding-top:clamp(1.75rem,3vw,3rem);container-type:inline-size}.reading-layout.svelte-1i4h1k2{grid-template-columns:minmax(0,1fr);align-items:start;gap:1.5rem;display:grid;container-type:inline-size}.lesson-outline.svelte-1i4h1k2{min-width:0;display:none}.lesson-sections.svelte-1i4h1k2{gap:clamp(2.75rem,4vw,4rem);min-width:0;display:grid}.lesson-chapter.svelte-1i4h1k2{gap:clamp(1.35rem,2.5vw,1.75rem);min-width:0;padding:0;scroll-margin-top:7rem;display:grid}.chapter-heading.svelte-1i4h1k2{align-items:center;gap:1rem;display:flex}.chapter-number.svelte-1i4h1k2{border-radius:var(--ds-radius-cell);width:3.5rem;height:3.5rem;color:var(--ds-on-dark);background:var(--chapter-fill);font:800 19px/1 var(--ds-font-ui);flex-shrink:0;justify-content:center;align-items:center;display:flex;box-shadow:inset 0 1px oklch(100% 0 0/.3)}.chapter-eyebrow.svelte-1i4h1k2{font:700 .7rem/1.25 var(--ds-font-ui);letter-spacing:.18em;text-transform:uppercase;color:var(--chapter-accent);margin:0 0 .3rem}.chapter-heading.svelte-1i4h1k2 h2:where(.svelte-1i4h1k2){font:800 clamp(1.55rem, 3.1vw, 2.5rem)/1.12 var(--ds-font-ui);letter-spacing:-.04em;overflow-wrap:anywhere;color:var(--ds-ink);margin:0}.chapter-content.svelte-1i4h1k2{min-width:0;max-width:78ch;font-size:clamp(1rem,1.2vw,1.075rem);line-height:1.75}@media (width>=1024px){.reading-layout.svelte-1i4h1k2{grid-template-columns:minmax(0,1fr) minmax(15rem,18rem);gap:clamp(1.75rem,4vw,4rem)}.lesson-article.svelte-1i4h1k2{grid-area:1/1}.lesson-outline.svelte-1i4h1k2{grid-area:1/2;height:100%;display:block}.outline-sticky.svelte-1i4h1k2{position:sticky;top:6.5rem}}@container (width<=61rem){.reading-layout.svelte-1i4h1k2{grid-template-columns:minmax(0,1fr)}.lesson-article.svelte-1i4h1k2{grid-area:auto/1}.lesson-outline.svelte-1i4h1k2{grid-area:auto;height:auto;display:none}}@media (width<=639px){.lesson-reader.svelte-1i4h1k2{padding-top:1rem}.chapter-heading.svelte-1i4h1k2{gap:.75rem}.chapter-number.svelte-1i4h1k2{border-radius:.65rem;width:2.8rem;height:2.8rem;font-size:17px}}