.public-lesson-page{min-height:100svh;overflow-x:clip;background:#fcfcfd}.lesson-reading-progress{height:4px;position:fixed;z-index:100;top:0;right:0;left:0;background:var(--color-line)}.lesson-reading-progress span{display:block;height:100%;background:var(--color-action);transition:width .12s linear}.lesson-site-header{position:relative;z-index:20;background:var(--color-paper)}.lesson-header-main{width:min(var(--layout-max),calc(100% - 2 * var(--layout-gutter)));min-height:5.25rem;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:var(--space-8);margin:0 auto}.lesson-brand{display:inline-flex;width:fit-content}.lesson-desktop-nav{display:flex;gap:clamp(var(--space-4),2vw,var(--space-8));color:var(--color-text-muted);font-size:var(--type-body-sm-size);font-weight:var(--font-weight-medium)}.lesson-desktop-nav a,.lesson-mobile-nav a{transition:color var(--duration-fast),border-color var(--duration-fast),background var(--duration-fast)}.lesson-desktop-nav a:hover{color:var(--color-action)}.lesson-header-action{min-height:2.75rem;display:inline-flex;align-items:center;justify-self:end;gap:var(--space-2);padding:0 var(--space-5);border-radius:var(--radius-round);background:var(--color-action);color:white;font-size:var(--type-body-sm-size);font-weight:var(--font-weight-semibold);font-variant-emoji:text;white-space:nowrap;transition:background var(--duration-fast)}.lesson-header-action:hover{background:var(--color-action-hover)}.lesson-mobile-nav{display:none}.lesson-hero{padding:clamp(3.5rem,7vw,6.5rem) var(--layout-gutter);background:linear-gradient(135deg,var(--color-brand-50),white 52%,var(--color-lilac-soft))}.lesson-hero__inner{width:min(64rem,100%);margin:0 auto}.lesson-hero__copy{min-width:0}.lesson-breadcrumbs{margin-bottom:var(--space-10);overflow:hidden;color:var(--color-text-muted);font-size:var(--type-caption-size)}.lesson-breadcrumbs ol{display:flex;margin:0;padding:0;overflow-x:auto;scrollbar-width:none;list-style:none;white-space:nowrap}.lesson-breadcrumbs ol::-webkit-scrollbar{display:none}.lesson-breadcrumbs li{display:flex;align-items:center}.lesson-breadcrumbs li:not(:last-child):after{content:"/";margin-inline:var(--space-2);color:var(--color-text-subtle)}.lesson-breadcrumbs a:hover{color:var(--color-action)}.lesson-label{margin:0 0 var(--space-4);color:var(--color-brand-700);font-size:var(--type-label-size);font-weight:var(--font-weight-semibold);letter-spacing:var(--type-label-tracking);text-transform:uppercase}.lesson-hero h1{max-width:14ch;margin:0 0 var(--space-6);font-size:clamp(3rem,6.3vw,5rem);font-weight:var(--font-weight-bold);letter-spacing:-.06em;line-height:.99;overflow-wrap:anywhere}.lesson-hero__copy[data-title-scale=compact] h1{max-width:17ch;font-size:clamp(2.75rem,5.2vw,4.5rem)}.lesson-hero__lead{max-width:42rem;margin:0 0 var(--space-8);color:var(--color-text-secondary);font-size:var(--type-body-lg-size);line-height:1.62}.lesson-meta{display:flex;flex-wrap:wrap;justify-content:flex-start;gap:var(--space-2);margin:0;text-align:left}.lesson-meta span{padding:var(--space-2) var(--space-3);border:1px solid rgb(0 150 255/.16);border-radius:var(--radius-round);background:rgb(255 255 255/.76);color:var(--color-brand-700);font-size:.6875rem;font-weight:var(--font-weight-semibold);letter-spacing:.07em;text-transform:uppercase}.lesson-updated{margin:var(--space-4) 0 0;color:var(--color-text-subtle);font-size:var(--type-caption-size)}.lesson-mobile-toc{display:none}.lesson-reading-layout{width:min(72rem,calc(100% - 2 * var(--layout-gutter)));display:grid;grid-template-columns:minmax(0,46rem) minmax(12rem,15rem);align-items:start;justify-content:center;gap:clamp(var(--space-10),6vw,var(--space-20));margin:clamp(4.5rem,8vw,7rem) auto}.lesson-reading-layout[data-has-toc=false]{grid-template-columns:minmax(0,46rem)}.lesson-toc{height:fit-content;grid-column:2;grid-row:1;align-self:start;max-height:calc(100svh - 9rem);position:sticky;top:7.5rem;overflow-y:auto;overscroll-behavior:contain;padding:var(--space-5) var(--space-2) var(--space-2) 0;border-top:2px solid var(--color-ink-950);scrollbar-width:thin;scrollbar-color:var(--color-line-strong) transparent}.lesson-toc>div{display:grid;gap:var(--space-2);margin-bottom:var(--space-4)}.lesson-toc>div p{margin:0;font-size:var(--type-body-sm-size);font-weight:var(--font-weight-bold);line-height:1.4}.lesson-toc>div span{color:var(--color-text-subtle);font-size:var(--type-caption-size);line-height:1.4}.lesson-toc nav{display:grid;gap:var(--space-1)}.lesson-mobile-toc a,.lesson-toc a{display:grid;grid-template-columns:1.75rem minmax(0,1fr);align-items:start;gap:var(--space-2);padding:var(--space-2) 0;color:var(--color-text-muted);font-size:var(--type-caption-size);line-height:1.5;transition:color var(--duration-fast),transform var(--duration-fast)}.lesson-mobile-toc a>span,.lesson-toc a>span{padding-top:.0625rem;color:var(--color-text-subtle);font-size:.625rem;line-height:1.5}.lesson-mobile-toc a[data-level=h3],.lesson-toc a[data-level=h3]{padding-left:var(--space-4);font-size:.6875rem}.lesson-mobile-toc a:hover,.lesson-mobile-toc a[data-active=true],.lesson-toc a:hover,.lesson-toc a[data-active=true]{color:var(--color-action);transform:translateX(3px)}.lesson-mobile-toc a[data-active=true]>span,.lesson-toc a[data-active=true]>span{color:var(--color-action)}.lesson-reading{grid-column:1;grid-row:1;display:grid;gap:var(--space-8);min-width:0}.lesson-reading-layout[data-has-toc=false] .lesson-reading{grid-column:1}.lesson-reading>.preview-h1{margin-top:var(--space-16);font-size:clamp(2.6rem,6vw,4rem)}.lesson-reading>.preview-h2{margin-top:3.5rem;font-size:clamp(2.15rem,5vw,3.25rem);line-height:1.06}.lesson-reading>.preview-h3{margin-top:var(--space-6);font-size:clamp(1.45rem,3vw,1.9rem)}.lesson-reading>.preview-paragraph{max-width:68ch;color:var(--color-ink-700);font-size:1.125rem;line-height:1.82}.lesson-reading>.preview-list{padding:var(--space-5);border:1px solid var(--color-brand-100);border-radius:var(--radius-md);background:var(--color-brand-50);font-size:1.0625rem}.lesson-reading>.audio-preview,.lesson-reading>.exercise-preview,.lesson-reading>.file-preview,.lesson-reading>.form-preview,.lesson-reading>.preview-image,.lesson-reading>.preview-table{margin-block:var(--space-4)}.section-hero{position:relative;padding:clamp(var(--space-16),9vw,var(--space-28)) var(--layout-gutter);overflow:hidden;background:linear-gradient(135deg,var(--color-brand-50),white 58%,var(--color-lilac-soft))}.section-hero:after{content:"";width:clamp(18rem,32vw,30rem);aspect-ratio:1;position:absolute;right:max(-10rem,-8vw);bottom:-65%;border:clamp(2.5rem,5vw,5rem) solid rgb(0 150 255/.1);border-radius:50%;pointer-events:none}.section-hero>div{width:min(64rem,100%);margin:0 auto}.section-hero .lesson-breadcrumbs{margin-bottom:var(--space-10)}.section-hero h1{max-width:13ch;margin:0 0 var(--space-6);font-size:clamp(3.25rem,7vw,5.5rem);font-weight:var(--font-weight-bold);letter-spacing:-.06em;line-height:.98}.section-hero>div>p:not(.hero-kicker){max-width:42rem;margin:0;color:var(--color-text-secondary);font-size:var(--type-body-lg-size);line-height:1.62}.section-page[data-section=vocabulary] .section-hero{background:linear-gradient(135deg,var(--color-coral-soft),white 58%,var(--color-yellow-soft))}.section-page[data-section=reading] .section-hero{background:linear-gradient(135deg,var(--color-mint-soft),white 58%,var(--color-brand-50))}.section-page[data-section=listening] .section-hero{background:linear-gradient(135deg,var(--color-yellow-soft),white 58%,var(--color-coral-soft))}.section-page[data-section=speaking] .section-hero{background:linear-gradient(135deg,var(--color-lilac-soft),white 58%,var(--color-brand-50))}.section-hero__facts{display:flex;flex-wrap:wrap;gap:var(--space-2);margin-top:var(--space-8)}.section-hero__facts span{padding:var(--space-2) var(--space-4);border:1px solid rgb(0 116 201/.14);border-radius:var(--radius-round);background:rgb(255 255 255/.68);color:var(--color-text-secondary);font-size:var(--type-caption-size);font-weight:var(--font-weight-semibold)}.section-lessons{width:min(var(--layout-max),calc(100% - 2 * var(--layout-gutter)));margin:clamp(var(--space-16),8vw,var(--space-24)) auto}.section-lessons__heading{margin-bottom:var(--space-10)}.section-lessons__heading>p{margin:0 0 var(--space-3);color:var(--color-brand-700);font-size:var(--type-label-size);font-weight:var(--font-weight-semibold);letter-spacing:var(--type-label-tracking);text-transform:uppercase}.section-lessons__heading h2{max-width:16ch;margin:0;font-size:clamp(2.25rem,5vw,4rem);letter-spacing:-.052em;line-height:1.03}.section-library-controls{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:var(--space-4);margin:var(--space-10) 0 var(--space-4);padding:var(--space-3);border:1px solid var(--color-border);border-radius:var(--radius-lg);background:white;box-shadow:var(--shadow-1)}.section-search{min-width:0;min-height:3.5rem;display:flex;align-items:center;gap:var(--space-3);padding-inline:var(--space-4);border:1px solid var(--color-border);border-radius:var(--radius-sm);background:var(--color-surface-subtle);color:var(--color-text-muted)}.section-search:focus-within{border-color:var(--color-action);background:white;box-shadow:0 0 0 3px var(--color-brand-12)}.section-search>span{font-size:1.65rem;line-height:1;transform:rotate(-18deg)}.section-search input{width:100%;min-width:0;height:3.375rem;border:0;outline:0;background:transparent;color:var(--color-text);font:inherit}.section-search input::placeholder{color:var(--color-text-subtle)}.section-levels{display:flex;flex-wrap:wrap;gap:var(--space-2)}.section-levels button{min-width:2.75rem;min-height:2.75rem;padding-inline:var(--space-4);border:1px solid var(--color-border);border-radius:var(--radius-round);background:white;color:var(--color-text-secondary);font:inherit;font-size:var(--type-caption-size);font-weight:var(--font-weight-semibold)}.section-levels button:hover{border-color:var(--color-action);color:var(--color-action)}.section-levels button[aria-pressed=true]{border-color:var(--color-action);background:var(--color-action);color:white}.section-results-summary{display:flex;align-items:center;justify-content:space-between;gap:var(--space-3);margin:var(--space-6) var(--space-1);color:var(--color-text-muted);font-size:var(--type-caption-size)}.section-results-summary b{color:var(--color-text)}.section-lessons__grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--space-5)}.section-lesson-card{--lesson-accent:var(--color-brand-500);min-height:20rem;display:flex;position:relative;flex-direction:column;padding:var(--space-6);overflow:hidden;border:1px solid var(--color-border);border-radius:var(--radius-lg);background:linear-gradient(155deg,color-mix(in srgb,var(--lesson-accent) 8%,white),white 52%);box-shadow:var(--shadow-1);transition:border-color var(--duration-base),box-shadow var(--duration-base),transform var(--duration-base)}.section-lesson-card:nth-child(4n+2){--lesson-accent:var(--color-mint)}.section-lesson-card:nth-child(4n+3){--lesson-accent:var(--color-lilac)}.section-lesson-card:nth-child(4n+4){--lesson-accent:var(--color-coral)}.section-lesson-card:after{content:"";width:8rem;height:8rem;position:absolute;top:-5.75rem;right:-3rem;border:1.4rem solid color-mix(in srgb,var(--lesson-accent) 20%,transparent);border-radius:50%}.section-lesson-card:hover{border-color:var(--color-brand-200);box-shadow:var(--shadow-2);transform:translateY(-4px)}.section-lesson-card>div{display:flex;flex-wrap:wrap;gap:var(--space-2)}.section-lesson-card>div span{padding:var(--space-1) var(--space-3);border-radius:var(--radius-round);background:color-mix(in srgb,var(--lesson-accent) 13%,white);color:var(--color-text-secondary);font-size:var(--type-caption-size);font-weight:var(--font-weight-semibold);text-transform:uppercase}.section-lesson-card h3{margin:var(--space-8) 0 var(--space-3);font-size:var(--type-title-lg-size);font-weight:var(--font-weight-bold);letter-spacing:var(--type-title-lg-tracking);line-height:var(--type-title-lg-line)}.section-lesson-card p{display:-webkit-box;margin:0 0 var(--space-8);overflow:hidden;color:var(--color-text-muted);font-size:var(--type-body-sm-size);line-height:var(--type-body-sm-line);-webkit-box-orient:vertical;-webkit-line-clamp:4}.section-lesson-card b{display:flex;align-items:center;gap:var(--space-2);margin-top:auto;color:var(--color-text-secondary);font-size:var(--type-caption-size);font-weight:var(--font-weight-semibold)}.section-lessons__empty{padding:var(--space-10);border:1px solid var(--color-border);border-radius:var(--radius-lg);background:var(--color-surface-subtle)}.section-lessons__empty strong{font-size:var(--type-body-lg-size)}.section-lessons__empty p{margin:var(--space-2) 0 0;color:var(--color-text-muted)}.section-lessons__empty button{min-height:2.75rem;margin-top:var(--space-5);padding-inline:var(--space-5);border:1px solid var(--color-border);border-radius:var(--radius-round);background:white;color:var(--color-action);font:inherit;font-weight:var(--font-weight-semibold)}.lesson-related{padding:clamp(var(--space-16),9vw,var(--space-28)) var(--layout-gutter);border-top:1px solid var(--color-border);background:var(--color-brand-50)}.lesson-related__heading{width:min(var(--layout-max),100%);display:flex;align-items:end;justify-content:space-between;gap:var(--space-8);margin:0 auto var(--space-10)}.lesson-related__heading p{margin:0 0 var(--space-3);color:var(--color-brand-700);font-size:var(--type-label-size);font-weight:var(--font-weight-semibold);letter-spacing:var(--type-label-tracking);text-transform:uppercase}.lesson-related__heading h2{max-width:18ch;margin:0;font-size:clamp(2.25rem,5vw,4rem);letter-spacing:-.052em;line-height:1.03}.lesson-related__heading>a{flex:0 0 auto;padding:var(--space-3) 0;color:var(--color-text-secondary);font-size:var(--type-body-sm-size);font-weight:var(--font-weight-semibold)}.lesson-related__heading>a:hover{color:var(--color-action)}.lesson-related__grid{width:min(var(--layout-max),100%);display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:var(--space-5);margin:0 auto}.lesson-related-card{min-height:22rem;display:flex;position:relative;flex-direction:column;overflow:hidden;padding:var(--space-6);border:1px solid var(--color-border);border-radius:var(--radius-lg);background:white;box-shadow:var(--shadow-1);transition:border-color var(--duration-base),box-shadow var(--duration-base),transform var(--duration-base)}.lesson-related-card:hover{border-color:var(--color-brand-200);box-shadow:var(--shadow-2);transform:translateY(-4px)}.lesson-related-card>div{display:flex;gap:var(--space-2)}.lesson-related-card>div span{padding:var(--space-1) var(--space-3);border-radius:var(--radius-round);background:var(--color-brand-50);color:var(--color-brand-700);font-size:.625rem;font-weight:var(--font-weight-semibold);text-transform:uppercase}.lesson-related-card h3{position:relative;z-index:1;margin:var(--space-8) 0 var(--space-3);font-size:clamp(1.35rem,2.4vw,1.8rem);letter-spacing:-.035em;line-height:1.15}.lesson-related-card p{display:-webkit-box;position:relative;z-index:1;margin:0 0 var(--space-8);overflow:hidden;color:var(--color-text-muted);font-size:var(--type-body-sm-size);line-height:1.6;-webkit-box-orient:vertical;-webkit-line-clamp:5}.lesson-related-card>i{position:absolute;right:-.2rem;bottom:-2.2rem;color:var(--color-brand-100);font-size:10rem;font-style:normal;font-weight:var(--font-weight-bold);letter-spacing:-.08em;line-height:1}.lesson-related-card>b{display:flex;position:relative;z-index:1;align-items:center;gap:var(--space-2);margin-top:auto;color:var(--color-text-secondary);font-size:var(--type-caption-size);font-weight:var(--font-weight-semibold)}.lesson-related-card:nth-child(2)>i{color:var(--color-mint)}.lesson-related-card:nth-child(3)>i{color:var(--color-lilac)}@media (max-width:68rem){.lesson-reading-layout{gap:var(--space-10)}}@media (max-width:56.25rem){.lesson-header-main{grid-template-columns:1fr auto;min-height:4.75rem;padding-top:var(--space-3)}.lesson-desktop-nav{display:none}.lesson-mobile-nav{width:min(var(--layout-max),calc(100% - 2 * var(--layout-gutter)));display:flex;gap:var(--space-2);margin:0 auto;padding:0 0 var(--space-3);overflow-x:auto;overscroll-behavior-x:contain;scroll-snap-type:x proximity;scrollbar-width:none}.lesson-mobile-nav::-webkit-scrollbar{display:none}.lesson-mobile-nav a{min-height:2.75rem;display:inline-flex;flex:0 0 auto;align-items:center;padding:0 var(--space-4);border:1px solid var(--color-border);border-radius:var(--radius-round);background:white;color:var(--color-text-secondary);font-size:var(--type-body-sm-size);font-weight:var(--font-weight-semibold);scroll-snap-align:start}.lesson-mobile-nav a:focus-visible,.lesson-mobile-nav a:hover{border-color:var(--color-brand-200);background:var(--color-brand-50);color:var(--color-brand-700)}.lesson-related__grid,.section-lessons__grid{grid-template-columns:repeat(2,minmax(0,1fr))}.lesson-related-card:last-child:nth-child(odd){grid-column:1/-1;min-height:18rem}}@media (max-width:48rem){.lesson-header-main{min-height:4.25rem;padding-top:var(--space-2)}.lesson-header-action{display:none}.lesson-hero{padding:var(--space-10) var(--space-4) var(--space-12);background:linear-gradient(180deg,var(--color-brand-50),white)}.lesson-breadcrumbs{margin-bottom:var(--space-6)}.lesson-label{margin-bottom:var(--space-3);font-size:.6875rem}.lesson-hero h1{max-width:none;margin-bottom:var(--space-5);font-size:clamp(2.3rem,11vw,3.35rem);letter-spacing:-.052em;line-height:1.01}.lesson-hero__copy[data-title-scale=compact] h1{font-size:clamp(2.1rem,9.5vw,2.85rem)}.lesson-hero__lead{margin-bottom:var(--space-6);font-size:1.0625rem;line-height:1.58}.lesson-meta{width:100%;flex-wrap:nowrap;overflow-x:auto;scrollbar-width:none}.lesson-meta::-webkit-scrollbar{display:none}.lesson-meta span{flex:0 0 auto;padding:var(--space-1) var(--space-3);background:white}.lesson-mobile-toc{width:calc(100% - 2 * var(--space-4));display:block;margin:var(--space-8) auto 0;border:1px solid var(--color-border);border-radius:var(--radius-md);background:white}.lesson-mobile-toc summary{min-height:3.75rem;display:grid;grid-template-columns:minmax(0,1fr) auto auto;align-items:center;gap:var(--space-3);padding:var(--space-3) var(--space-4);cursor:pointer;list-style:none}.lesson-mobile-toc summary::-webkit-details-marker{display:none}.lesson-mobile-toc__title{font-size:var(--type-body-sm-size);font-weight:var(--font-weight-semibold);line-height:1.4}.lesson-mobile-toc__count{min-width:1.75rem;height:1.75rem;display:grid;place-items:center;border-radius:var(--radius-round);background:var(--color-brand-100);color:var(--color-brand-700);font-size:.625rem;font-weight:var(--font-weight-semibold);line-height:1}.lesson-mobile-toc__chevron{width:.55rem;height:.55rem;border-right:1.5px solid var(--color-text-muted);border-bottom:1.5px solid var(--color-text-muted);transform:rotate(45deg) translateY(-.125rem);transition:transform var(--duration-fast)}.lesson-mobile-toc[open] .lesson-mobile-toc__chevron{transform:rotate(225deg) translate(-.125rem,-.125rem)}.lesson-mobile-toc nav{display:grid;gap:var(--space-1);padding:var(--space-3) var(--space-4) var(--space-4);border-top:1px solid var(--color-border)}.lesson-reading-layout,.lesson-reading-layout[data-has-toc=false]{grid-template-columns:1fr;width:calc(100% - 2 * var(--space-4));margin:var(--space-10) auto}.lesson-toc{display:none}.lesson-reading{grid-column:1;grid-row:auto;gap:var(--space-6)}.lesson-reading>.preview-h1{margin-top:var(--space-10);font-size:clamp(2.1rem,10vw,2.85rem)}.lesson-reading>.preview-h2{margin-top:var(--space-8);font-size:clamp(1.85rem,9vw,2.5rem)}.lesson-reading>.preview-h3{margin-top:var(--space-4);font-size:clamp(1.35rem,7vw,1.75rem)}.lesson-reading>.preview-paragraph{font-size:1.025rem;line-height:1.75}.lesson-reading>.preview-list{padding:var(--space-4);font-size:1rem}.section-hero{padding:var(--space-12) var(--space-4)}.section-hero .lesson-breadcrumbs{margin-bottom:var(--space-6)}.section-hero h1{margin-bottom:var(--space-5);font-size:clamp(2.6rem,13vw,4rem)}.section-hero>div>p:not(.hero-kicker){font-size:1.0625rem;line-height:1.58}.section-lessons{width:calc(100% - 2 * var(--space-4));margin:var(--space-16) auto}.section-lessons__heading{margin-bottom:var(--space-8)}.section-library-controls{grid-template-columns:1fr;padding:var(--space-3)}.section-levels{flex-wrap:nowrap;overflow-x:auto;padding-bottom:var(--space-1);scrollbar-width:none}.section-levels::-webkit-scrollbar{display:none}.section-levels button{flex:0 0 auto}.section-lessons__grid{grid-template-columns:1fr}.section-lesson-card{min-height:18rem}.exercise-preview,.form-preview{border-radius:var(--radius-md)}.exercise-preview__actions{align-items:stretch;flex-direction:column-reverse}.exercise-check{width:100%}.image-match-grid{grid-template-columns:1fr}.file-preview{grid-template-columns:auto minmax(0,1fr)}.file-preview>a{grid-column:1/-1;justify-content:center}.form-preview>button{width:100%}.lesson-related{padding:var(--space-16) var(--space-4)}.lesson-related__heading{align-items:flex-start;flex-direction:column;margin-bottom:var(--space-8)}.lesson-related__heading h2{font-size:clamp(2.1rem,10vw,3rem)}.lesson-related__grid{grid-template-columns:1fr}.lesson-related-card,.lesson-related-card:last-child:nth-child(odd){grid-column:auto;min-height:19rem}}