:root{--lesson-surface:#fff;--bg:#f5f7f4;--panel:#fff;--text:#20372a;--muted:#56675c;--border:#d9e2d9;--accent:#216946;--accent-soft:#e6f2e8;--code:#f0f3f0;--focus:#155fce;--incorrect:#973516;--correct:#226945;--header-height:72px;--navigation-bg:#edf1f4;--navigation-dot:#b5c2ce;--execution-controls-bg:#cddae5;--controls-border:#c1cdd7;--controls-shadow:#182b3a18;color-scheme:light}
:root[data-theme=dark]{--lesson-surface:#000;--bg:#111a15;--panel:#1a261f;--text:#e2eee4;--muted:#b0c2b4;--border:#3a4c40;--accent:#8cd8ad;--accent-soft:#243f30;--code:#142019;--focus:#8dbfff;--incorrect:#ffb092;--correct:#98dfb5;--navigation-bg:#182127;--navigation-dot:#435765;--execution-controls-bg:#304352;--controls-border:#3b4b56;--controls-shadow:#0005;color-scheme:dark}
*{box-sizing:border-box}body.interactive-course{margin:0;background:var(--bg);color:var(--text);font:var(--text-body)/var(--leading-body) var(--font-text)}a{color:var(--accent);text-underline-offset:3px}button,input,select{font:inherit}button,select{border:1px solid var(--border);border-radius:9px;background:var(--panel);color:var(--text);padding:9px 15px}button,a,select{touch-action:manipulation}button{cursor:pointer}button:hover{background:var(--accent-soft)}button:disabled{opacity:.5;cursor:default}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible,pre:focus-visible{outline:3px solid var(--focus);outline-offset:3px}h1,h2,h3{line-height:1.2;letter-spacing:-.025em}h1{font-size:clamp(30px,4vw,43px);margin:10px 0 24px}h2{font-size:28px;margin:0 0 22px}h3{font-size:20px}p{margin:0 0 18px}code,pre{font-family:ui-monospace,SFMono-Regular,Consolas,monospace}code{background:var(--code);border-radius:4px;padding:2px 4px}pre{white-space:pre;overflow:auto;max-width:100%;background:var(--code);padding:18px;border-radius:12px;border:1px solid var(--border);font-size:var(--text-code);line-height:1.7}pre code{padding:0;background:transparent}img{max-width:100%;height:auto}table{border-collapse:collapse;display:block;overflow:auto;max-width:100%}td,th{padding:10px;border:1px solid var(--border)}[hidden]{display:none!important}.js-control{display:none}.enhanced .js-control{display:flex}.enhanced .quiz-fallback{display:none}.skip-link{position:fixed;top:-80px;z-index:20;background:var(--panel);padding:12px}.skip-link:focus{top:5px}.header-container{position:sticky;top:0;z-index:10;border-bottom:1px solid var(--border);background:var(--panel)}header{height:var(--header-height);display:flex;align-items:center;justify-content:space-between;gap:18px;padding:0 28px}.header-left,.header-right,.site-icon-title{display:flex;align-items:center;gap:12px}.site-icon-title{cursor:pointer}.site-icon-title p{margin:0;font-size:20px;font-weight:750}.logo{width:36px;height:36px}.leftnav-toggle-button{display:none}.bar{display:block;background:var(--text);height:2px;width:20px;margin:4px 0}.header-site-nav{display:flex;gap:24px}.header-nav-menu{position:relative}.header-nav-menu summary{cursor:pointer}.header-dropdown-panel{position:absolute;top:38px;right:0;width:400px;max-width:85vw;padding:24px;display:grid;gap:18px;grid-template-columns:1fr 1fr;background:var(--panel);border:1px solid var(--border);border-radius:12px;box-shadow:0 12px 28px #0002}.header-dropdown-section{display:flex;flex-direction:column;gap:6px}.header-dropdown-heading{font-weight:700}.header-dropdown-panel a{font-size:14px;text-decoration:none}.header-nav-chevron{margin-left:8px}.course-shell{display:grid;grid-template-columns:var(--sidebar-width) minmax(0,1fr);width:100%;max-width:none;margin:0}.course-sidebar{position:sticky;top:var(--header-height);height:calc(100dvh - var(--header-height));overflow-y:auto;padding:24px 20px 100px;border-right:1px solid var(--border)}.sidebar-heading{display:flex;justify-content:space-between;font-weight:750;font-size:19px}.drawer-close{display:none!important}.course-progress{font-size:13px;color:var(--muted);margin:12px 0 25px}.lesson-group{margin-bottom:15px}.lesson-group-heading{font-size:13px;font-weight:700}.lesson-group ol{list-style:none;padding:8px 0;margin:0}.lesson-group a{padding:7px 10px;display:flex;justify-content:space-between;gap:8px;font-size:14px;color:var(--muted);text-decoration:none;border-radius:7px}.lesson-group a[aria-current=page]{background:var(--accent-soft);color:var(--accent);font-weight:700}.lesson-status{font-size:12px}.compiler-link{display:block;padding:14px 0;font-size:14px}.lesson-main{min-width:0;padding:38px clamp(20px,5vw,80px) 135px;max-width:1120px;width:100%;margin:0 auto;align-self:start}.course-breadcrumb{font-size:13px;font-weight:650;text-decoration:none;color:var(--muted)}.section-current{font-size:14px;color:var(--muted);margin-bottom:20px}.section-map{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 28px}.section-link{display:flex;align-items:center;gap:6px;border:1px solid var(--border);padding:6px 9px;border-radius:8px;font-size:12px;text-decoration:none;color:var(--text);background:var(--panel)}.section-link[data-type=concept]{border-bottom:3px solid #648cce}.section-link[data-type=code]{border-bottom:3px solid #469273}.section-link[data-type=quiz]{border-bottom:3px solid #b88237}.section-link[data-type=recap]{border-bottom:3px solid #9a6aaa}.section-link[aria-current=step]{outline:2px solid var(--accent);outline-offset:1px}.section-number{font-weight:750}.map-status{font-size:11px}.lesson-section{background:var(--lesson-surface);padding:0;border:0;border-radius:0;margin-bottom:24px;overflow-wrap:anywhere}.section-prose>:last-child{margin-bottom:0}.lesson-controls{position:fixed;bottom:0;left:270px;right:0;padding:15px 32px max(15px,env(safe-area-inset-bottom));align-items:center;justify-content:space-between;background-color:var(--navigation-bg);background-image:radial-gradient(circle,var(--navigation-dot) 1px,transparent 1.2px);background-size:10px 10px;background-repeat:repeat;border-top:1px solid var(--controls-border);z-index:8;gap:12px}.lesson-controls [data-continue],.start-learning,.next-lesson,.check-answer{background:var(--accent);color:var(--panel);font-weight:650;border:0}.next-lesson,.start-learning{display:inline-block;padding:12px 22px;border-radius:10px;text-decoration:none}.lesson-controls span{color:var(--muted);font-size:var(--text-label);background:var(--navigation-bg);border-radius:7px;padding:4px 8px}.lesson-player{min-width:0}.simulation-note{color:var(--muted);font-size:13px}.sample-input{display:flex;flex-wrap:wrap;align-items:center;gap:14px;margin-bottom:24px;font-size:14px}.sample-input select{max-width:100%}.player-grid{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,1fr);gap:20px}.code-pane,.state-pane{min-width:0}.pane-title{font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.09em;color:var(--muted);margin-bottom:8px}.trace-code{margin:0;padding:14px 0}.trace-line{display:block;padding:0 14px;border-left:3px solid transparent}.trace-line.active-line{background:var(--accent-soft);border-left-color:var(--accent);font-weight:600}.value-diagram{min-height:80px;margin-bottom:18px;font-size:var(--text-code)}.value-row{display:flex;align-items:center;gap:8px;margin:8px 0}.name-node{font-family:monospace;border:1px solid var(--border);border-radius:7px;padding:6px 10px;max-width:45%;overflow-wrap:anywhere}.reference-arrow{color:var(--accent);font-weight:800}.object-node{display:inline-flex;flex-direction:column;border:1px solid var(--border);border-radius:9px;padding:7px 10px;min-width:0;max-width:100%;background:var(--code);overflow-wrap:anywhere}.object-node code{white-space:pre-wrap}.object-node small{color:var(--muted);font-size:var(--text-code)}.object-pool{display:flex;flex-wrap:wrap;gap:6px;margin:16px 0;font-size:var(--text-code)}.calculation{color:var(--accent);font-family:monospace;font-size:var(--text-code)}.player-output{min-height:65px;margin:0 0 16px;white-space:pre-wrap}.player-explanation{margin-top:22px;padding:16px;border-left:3px solid var(--accent);background:var(--accent-soft);border-radius:0 8px 8px 0}.player-controls{flex-wrap:wrap;align-items:center;gap:8px}.player-controls span{color:var(--muted);font-size:var(--text-label);margin-left:auto}.prediction{align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px;border:1px solid var(--border);border-radius:12px;padding:15px;margin:20px 0}.prediction p{margin:0;font-size:14px}.player-error{color:var(--incorrect)}.lesson-quiz fieldset{border:0;margin:0;padding:0}.lesson-quiz legend{font-size:var(--text-heading);font-weight:650;margin-bottom:18px}.quiz-option{display:flex;align-items:flex-start;gap:12px;padding:15px;margin-bottom:10px;border:1px solid var(--border);border-radius:10px;cursor:pointer;white-space:pre-wrap}.quiz-option:has(input:checked){border-color:var(--accent);background:var(--accent-soft)}.quiz-option input{margin-top:7px;accent-color:var(--accent);flex-shrink:0}.check-answer{margin-top:12px}.quiz-feedback{margin-top:20px}.quiz-feedback.correct{color:var(--correct)}.quiz-feedback.retry{color:var(--incorrect)}.recap-status{color:var(--muted)}.unfinished-quizzes{padding-left:20px}.legacy-details{margin-top:24px}.legacy-details summary{cursor:pointer;font-weight:650}.legacy-details[open]>div{margin-top:20px}.legacy-controls{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin:12px 0}.legacy-message{padding:12px;background:var(--accent-soft);border-radius:8px}.legacy-line{display:block;padding:0 4px}.legacy-line.active-line{background:var(--accent-soft);border-left:3px solid var(--accent)}.legacy-output-line{opacity:.4}.legacy-output-line.revealed{opacity:1;font-weight:650}.legacy-code-wrapper{max-width:100%;margin:20px 0}.practice_program{margin-bottom:20px}.course-home{max-width:1120px;margin:auto;padding:60px 28px 0}.home-hero{max-width:760px;margin:0 auto 60px;text-align:center}.home-hero h1{font-size:clamp(38px,5.5vw,64px);line-height:1.12}.home-hero>p{font-size:19px;color:var(--muted)}.home-hero .home-note{font-size:13px;margin-top:20px}.home-preview{background:var(--panel);border:1px solid var(--border);border-radius:20px;padding:clamp(20px,4vw,45px);margin-bottom:55px}.home-flow{margin-bottom:55px}.flow-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:24px}.flow-grid article{border-top:2px solid var(--accent);padding:15px 0}.flow-grid p{color:var(--muted)}.course-catalog{margin-bottom:60px}.catalog-group{padding:24px;border:1px solid var(--border);border-radius:14px;margin:15px 0;background:var(--panel)}.catalog-group ol{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px 35px;padding-left:25px}.catalog-group a{display:flex;justify-content:space-between;gap:10px;text-decoration:none}.site-footer{padding:35px 0;border-top:1px solid var(--border);color:var(--muted);font-size:14px}.footer-main,.footer-links,.footer-bottom{display:flex;flex-wrap:wrap;gap:30px}.footer-column{display:flex;flex-direction:column}.footer-column h2{font-size:16px}.footer-brand{max-width:300px}.footer-profile{margin-bottom:25px}.footer-logo{font-size:22px;font-weight:700}.confetti-piece{position:fixed;left:var(--x);top:-15px;width:8px;height:12px;background:var(--color);pointer-events:none;z-index:15;animation:confetti-fall 1200ms ease-in forwards}@keyframes confetti-fall{to{transform:translateY(85vh) rotate(240deg);opacity:0}}
@media(max-width:900px){header{padding:0 18px}.header-site-nav{gap:12px;font-size:13px}.site-icon-title p{font-size:16px}.course-shell{grid-template-columns:var(--sidebar-width) minmax(0,1fr)}.course-sidebar{padding:20px 12px}.lesson-controls{left:230px;padding-left:20px;padding-right:20px}.lesson-main{padding:25px 20px 135px}.player-grid{grid-template-columns:1fr}.lesson-section h2{font-size:var(--text-heading)}}
@media(max-width:650px){:root{--header-height:66px}.header-site-nav{display:none}.header-left{gap:8px}.site-icon-title .logo{width:28px;height:28px}.header-right button{font-size:12px;padding:7px}.enhanced .leftnav-toggle-button{display:block;padding:5px}.course-shell{display:block}.course-sidebar{position:static;height:auto;border-right:0}.enhanced .course-sidebar{display:none;position:fixed;top:var(--header-height);left:0;bottom:0;width:min(330px,100vw);height:auto;z-index:12;background:var(--panel);box-shadow:5px 0 30px #0004}.enhanced .course-sidebar.drawer-open{display:block}.enhanced .drawer-close{display:block!important}.lesson-main{padding:24px 14px 125px}.lesson-controls{left:0;padding:12px 14px max(12px,env(safe-area-inset-bottom))}.lesson-controls button{font-size:var(--text-label);padding:10px 12px}.lesson-section{padding:0;border-radius:0}.section-link{font-size:11px;padding:5px 7px}.section-map{gap:7px}.player-controls button{font-size:var(--text-label);padding:8px 10px}.catalog-group ol{grid-template-columns:1fr}.flow-grid{grid-template-columns:1fr;gap:8px}.course-home{padding:35px 16px 0}.header-dropdown-panel{position:fixed;top:65px;left:10px}.object-node{font-size:var(--text-code)}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}
.sr-only{position:absolute!important;width:1px!important;height:1px!important;padding:0!important;margin:-1px!important;overflow:hidden!important;clip:rect(0,0,0,0)!important;white-space:nowrap!important;border:0!important}.scope-label{font-size:var(--text-code);color:var(--muted);margin:0 0 10px}.reference-target{font-size:var(--text-code);color:var(--accent);font-weight:650}
.interactive-course #theme-toggle-btn{display:inline-flex;align-items:center;justify-content:center;width:40px;height:40px;padding:9px;border:0;border-radius:50%;background:transparent;flex-shrink:0}.interactive-course #theme-toggle-btn:hover{background:var(--accent-soft)}.interactive-course #theme-toggle-btn svg{width:22px;height:22px;display:block}
/* Keep course context visible while the lesson list scrolls. */
.course-sidebar{display:flex;flex-direction:column;padding:26px 14px 18px;overflow:hidden;gap:0}.sidebar-heading{padding:0 10px;align-items:center}.sidebar-heading>a{color:var(--text);text-decoration:none;font-size:20px}.sidebar-progress{padding:0 10px 22px}.sidebar-progress .course-progress{font-size:12px;line-height:1.6;margin:10px 0 12px}.sidebar-progress progress{display:block;width:100%;height:5px;border:0;border-radius:10px;overflow:hidden;background:var(--border);accent-color:var(--accent)}.sidebar-progress progress::-webkit-progress-bar{background:var(--border);border-radius:10px}.sidebar-progress progress::-webkit-progress-value{background:var(--accent);border-radius:10px}.sidebar-progress progress::-moz-progress-bar{background:var(--accent);border-radius:10px}.sidebar-lessons{min-height:0;overflow-y:auto;overscroll-behavior:contain;scrollbar-width:thin;scrollbar-color:var(--border) transparent;flex:1;padding:0 2px 18px}.lesson-group{margin-bottom:8px}.lesson-group-heading{display:flex;align-items:center;gap:10px;padding:12px 8px;font-size:12px;letter-spacing:.01em;color:var(--muted);list-style:none;border-radius:8px}.lesson-group-heading>span:first-child{flex:1}.group-count{font-size:10px;font-weight:500;min-width:22px;text-align:center;background:var(--code);padding:1px 5px;border-radius:5px}.lesson-group ol{padding:2px 0 6px 0}.lesson-group a{align-items:flex-start;justify-content:flex-start;gap:9px;padding:9px 10px;margin:2px 0;font-size:13px;line-height:1.5;border:1px solid transparent}.lesson-group a:hover{background:var(--accent-soft);color:var(--text)}.lesson-group a[aria-current=page]{border-color:var(--border);box-shadow:inset 3px 0 0 var(--accent)}.lesson-number{font-size:10px;line-height:1.95;font-variant-numeric:tabular-nums;color:var(--muted);min-width:21px}.lesson-title{flex:1;min-width:0}.lesson-group .lesson-status{font-size:10px;max-width:45px;line-height:1.5;color:var(--accent)}.lesson-group .lesson-status:empty{display:none}.course-sidebar .compiler-link{flex-shrink:0;margin:0 8px;padding:14px 4px 0;border-top:1px solid var(--border);font-size:13px;font-weight:650;text-decoration:none}.course-sidebar .drawer-close{border:0;font-size:22px;padding:0 8px}.enhanced .course-sidebar.drawer-open{display:flex}@media(max-width:650px){.course-sidebar{overflow:visible}.enhanced .course-sidebar{overflow:hidden;padding:22px 14px 18px}.sidebar-lessons{overflow-y:auto}}
/* Sections sit beneath the current lesson, leaving the workspace clear. */
.course-sidebar .section-map{display:flex;flex-direction:column;gap:1px;margin:6px 0 14px 20px;padding:2px 0 2px 10px;border-left:1px solid var(--border)}.course-sidebar .section-link{display:flex;align-items:flex-start;gap:8px;margin:0;padding:7px 8px;font-size:12px;font-weight:400;line-height:1.5;border:0;border-radius:6px;background:transparent;box-shadow:none;color:var(--muted)}.course-sidebar .section-link[aria-current=step]{background:var(--accent-soft);color:var(--accent);font-weight:650;box-shadow:inset 2px 0 0 var(--accent)}.course-sidebar .section-link:hover{color:var(--text);background:var(--accent-soft)}.section-title{flex:1;min-width:0}.course-sidebar .section-number{min-width:16px;font-size:10px;line-height:1.8;color:var(--muted)}.course-sidebar .map-status{font-size:12px;color:var(--accent);min-width:12px;text-align:right}.course-sidebar .lesson-status{min-width:12px;max-width:none;font-size:13px;line-height:1.5}
/* Numbered learning paths: active location and earned completion are distinct. */
:root{--path-neutral:#e8eeea;--path-complete:#d7ebdd;--path-line:#c5d9cb}:root[data-theme=dark]{--path-neutral:#29382e;--path-complete:#294b37;--path-line:#52765f}
.lesson-group ol>li{position:relative}.lesson-group ol>li::before,.lesson-group ol>li::after{content:'';position:absolute;left:24px;width:2px;top:25px;bottom:-25px;background:var(--border);pointer-events:none}.lesson-group ol>li::after{background:var(--path-line);transform:scaleY(0);transform-origin:top}.lesson-group ol>li.path-connected::after{transform:scaleY(1)}.lesson-group ol>li:last-child::before,.lesson-group ol>li:last-child::after{display:none}.lesson-group a[data-lesson-link]{position:relative;align-items:center;gap:10px;padding:8px 10px}.lesson-number{position:relative;z-index:1;display:grid;place-items:center;flex-shrink:0;width:28px;height:28px;min-width:28px;border-radius:50%;background:var(--path-neutral);color:var(--muted);font-size:10px;line-height:1;font-weight:600}.is-complete>.lesson-number,.is-complete>.section-number{background:var(--path-complete);color:var(--accent)}.lesson-group a[aria-current=page]{box-shadow:none;background:transparent;border-color:transparent;color:var(--text)}.lesson-group a[aria-current=page]>.lesson-number{outline:2px solid var(--accent);outline-offset:2px}.course-sidebar .lesson-status,.course-sidebar .map-status{display:none}.course-sidebar .section-map{margin:3px 0 12px 24px;padding:0 0 0 8px;border-left:0;gap:0}.course-sidebar .section-link{position:relative;align-items:center;padding:7px 8px;gap:9px;overflow:visible}.course-sidebar .section-number{position:relative;z-index:1;display:grid;place-items:center;flex-shrink:0;min-width:22px;width:22px;height:22px;border-radius:50%;background:var(--path-neutral);font-size:10px;line-height:1;font-weight:500}.course-sidebar .is-complete>.section-number{background:var(--path-complete);color:var(--accent)}.course-sidebar .section-link::before,.course-sidebar .section-link::after{content:'';position:absolute;left:18px;width:2px;top:18px;bottom:-18px;background:var(--border);pointer-events:none}.course-sidebar .section-link::after{background:var(--path-line);transform:scaleY(0);transform-origin:top}.course-sidebar .section-link.path-connected::after{transform:scaleY(1)}.course-sidebar .section-link:last-child::before,.course-sidebar .section-link:last-child::after{display:none}.course-sidebar .section-link[aria-current=step]{background:transparent;box-shadow:none;color:var(--accent)}.course-sidebar .section-link[aria-current=step]>.section-number{outline:2px solid var(--accent);outline-offset:2px}.path-new-connection::after{animation:path-connect 260ms ease-out both}.path-new-circle>.lesson-number,.path-new-circle>.section-number{animation:path-circle 320ms 260ms ease-out both}@keyframes path-connect{from{transform:scaleY(0)}to{transform:scaleY(1)}}@keyframes path-circle{0%{background:var(--path-neutral);transform:scale(1)}55%{background:var(--path-complete);transform:scale(1.16)}100%{background:var(--path-complete);transform:scale(1)}}@media(prefers-reduced-motion:reduce){.path-new-connection::after,.path-new-circle>.lesson-number,.path-new-circle>.section-number{animation:none}}
/* Execution controls stay within their player. */
.player-controls,.legacy-controls{position:static;background:var(--panel);border:1px solid var(--border);border-radius:10px;padding:10px;margin:0 0 20px;box-shadow:0 3px 10px #00000008;min-height:64px}.player-controls button,.legacy-controls button{flex:0 0 auto;min-width:64px;white-space:nowrap}.player-controls [data-action=next],.legacy-controls button:nth-child(2){min-width:100px}.player-controls span,.legacy-controls span{font-variant-numeric:tabular-nums;white-space:nowrap;min-width:84px;margin-left:auto;text-align:right}.legacy-controls button{font-size:var(--text-label);padding:8px 10px}@media(max-width:650px){.player-controls,.legacy-controls{gap:6px;padding:9px;margin-bottom:18px;min-height:91px;top:calc(var(--header-height) + 6px)}.player-controls button,.legacy-controls button{min-width:48px;font-size:var(--text-label);padding:8px}.player-controls [data-action=next],.legacy-controls button:nth-child(2){min-width:78px}.player-controls span,.legacy-controls span{flex-basis:100%;font-size:var(--text-label);text-align:right;line-height:1.4}}
@media(max-width:650px){.player-controls button,.legacy-controls button{flex-basis:54px;width:54px;padding:8px 5px}.player-controls [data-action=next],.legacy-controls button:nth-child(2){flex-basis:78px;width:78px}}
/* A single floating execution bar sits above lesson navigation. */
:root{--lesson-nav-height:78px}

/* Keep both bottom bars inside the centered course workspace on wide screens. */
:root{--course-gutter:0px;--sidebar-width:clamp(250px,20vw,360px)}.lesson-controls{left:calc(var(--course-gutter) + var(--sidebar-width));right:var(--course-gutter);padding-left:clamp(20px,3vw,40px);padding-right:clamp(20px,3vw,40px)}.player-controls button[data-action],.legacy-controls button[data-action]{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-width:0;width:auto;flex:0 0 auto;height:40px;border:0;border-radius:11px;font-size:var(--text-label);font-weight:600;padding:0 12px;background:transparent;transition:background 140ms ease,transform 140ms ease}.player-controls button[data-action]:hover,.legacy-controls button[data-action]:hover{background:var(--accent-soft)}.player-controls button[data-action]:active,.legacy-controls button[data-action]:active{transform:scale(.96)}.player-controls button[data-action=play],.legacy-controls button[data-action=play]{background:var(--accent);color:var(--panel);min-width:90px}.player-controls button[data-action=next],.legacy-controls button[data-action=next]{background:var(--accent-soft);color:var(--accent);min-width:108px}.player-controls button[data-action=back],.player-controls button[data-action=reset],.legacy-controls button[data-action=back],.legacy-controls button[data-action=reset]{font-size:0;padding:0;width:40px;flex-basis:40px;color:var(--muted)}.player-controls button[data-action]::before,.legacy-controls button[data-action]::before{content:"";width:17px;height:17px;flex:0 0 17px;background:currentColor;mask:var(--control-icon) center/contain no-repeat;-webkit-mask:var(--control-icon) center/contain no-repeat}.player-controls span[data-counter],.legacy-controls>span{font-size:var(--text-label);min-width:78px;padding:5px 8px;border-radius:7px;background:var(--code);color:var(--muted);line-height:1.4}
.player-controls button[data-action=back],.legacy-controls button[data-action=back]{--control-icon:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20stroke%3D%22black%22%20stroke-width%3D%221.8%22%20stroke-linecap%3D%22round%22%20stroke-linejoin%3D%22round%22%3E%3Cpath%20d%3D%22m14%206-6%206%206%206%22%2F%3E%3Cpath%20d%3D%22M5%205v14%22%2F%3E%3C%2Fsvg%3E")}
.player-controls button[data-action=next],.legacy-controls button[data-action=next]{--control-icon:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20stroke%3D%22black%22%20stroke-width%3D%221.8%22%20stroke-linecap%3D%22round%22%20stroke-linejoin%3D%22round%22%3E%3Cpath%20d%3D%22m10%206%206%206-6%206%22%2F%3E%3Cpath%20d%3D%22M19%205v14%22%2F%3E%3C%2Fsvg%3E")}
.player-controls button[data-action=play],.legacy-controls button[data-action=play]{--control-icon:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20stroke%3D%22black%22%20stroke-width%3D%221.8%22%20stroke-linecap%3D%22round%22%20stroke-linejoin%3D%22round%22%3E%3Cpath%20d%3D%22m8%205%2011%207-11%207z%22%2F%3E%3C%2Fsvg%3E")}
.player-controls button[data-action=play][data-playing=true],.legacy-controls button[data-action=play][data-playing=true]{--control-icon:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20stroke%3D%22black%22%20stroke-width%3D%221.8%22%20stroke-linecap%3D%22round%22%20stroke-linejoin%3D%22round%22%3E%3Cpath%20d%3D%22M8%205v14M16%205v14%22%2F%3E%3C%2Fsvg%3E")}
.player-controls button[data-action=reset],.legacy-controls button[data-action=reset]{--control-icon:url("data:image/svg+xml,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20viewBox%3D%220%200%2024%2024%22%20fill%3D%22none%22%20stroke%3D%22black%22%20stroke-width%3D%221.8%22%20stroke-linecap%3D%22round%22%20stroke-linejoin%3D%22round%22%3E%3Cpath%20d%3D%22M3%2010a9%209%200%201%201%202%208M3%204v6h6%22%2F%3E%3C%2Fsvg%3E")}
@media(max-width:900px){:root{--sidebar-width:250px}}@media(max-width:650px){:root{--sidebar-width:0px}.lesson-controls{padding-left:14px;padding-right:14px}}@media(prefers-reduced-motion:reduce){.player-controls button[data-action],.legacy-controls button[data-action]{transition:none}}
/* Syntax colours complement the active execution line in either theme. */
.interactive-course{--syntax-comment:#657668;--syntax-keyword:#8045a0;--syntax-string:#226b43;--syntax-number:#965321;--syntax-function:#24648e;--syntax-operator:#4b6056}:root[data-theme=dark] .interactive-course{--syntax-comment:#9cad9e;--syntax-keyword:#d7adf5;--syntax-string:#9cdbac;--syntax-number:#efbd8b;--syntax-function:#9dcbf3;--syntax-operator:#c1d2c6}.interactive-course pre .token{background:transparent;font-style:normal;text-shadow:none}.interactive-course pre .token.comment,.interactive-course pre .token.prolog{color:var(--syntax-comment)}.interactive-course pre .token.keyword,.interactive-course pre .token.boolean{color:var(--syntax-keyword)}.interactive-course pre .token.string,.interactive-course pre .token.char{color:var(--syntax-string)}.interactive-course pre .token.number{color:var(--syntax-number)}.interactive-course pre .token.function,.interactive-course pre .token.builtin,.interactive-course pre .token.class-name,.interactive-course pre .token.decorator{color:var(--syntax-function)}.interactive-course pre .token.operator,.interactive-course pre .token.punctuation{color:var(--syntax-operator)}.interactive-course pre .token.interpolation-punctuation{color:var(--syntax-keyword)}.trace-line.active-line,.legacy-line.active-line{font-weight:400}
/* Current section: a breathing circular marker, without a row outline. */
.course-sidebar .section-link[aria-current=step],.course-sidebar .section-link:focus-visible{outline:none}.course-sidebar .section-link[aria-current=step]>.section-number{outline:none;background:var(--accent);color:var(--panel);font-weight:700;box-shadow:0 0 0 3px var(--accent-soft)}.course-sidebar .section-link[aria-current=step]>.section-number::after{content:'';position:absolute;inset:-4px;border:1px solid var(--accent);border-radius:50%;pointer-events:none;animation:current-section-pulse 2600ms ease-out infinite}.course-sidebar .section-link:focus-visible>.section-number{outline:3px solid var(--focus);outline-offset:4px}@keyframes current-section-pulse{0%,15%{transform:scale(1);opacity:.35}75%,100%{transform:scale(1.45);opacity:0}}@media(prefers-reduced-motion:reduce){.course-sidebar .section-link[aria-current=step]>.section-number::after{animation:none;opacity:.22;transform:none}}
/* Section headings receive navigation focus without a decorative focus ring. */
.lesson-section>h2[tabindex="-1"]:focus{outline:none}
/* Code keeps an editor-style dark surface, independent of the page theme. */
.interactive-course pre{background:#17211c;color:#e1eae4;border-color:#35483c;color-scheme:dark;--syntax-comment:#9cad9e;--syntax-keyword:#d7adf5;--syntax-string:#9cdbac;--syntax-number:#efbd8b;--syntax-function:#9dcbf3;--syntax-operator:#c1d2c6}.interactive-course pre code{color:inherit;background:transparent}.interactive-course pre .trace-line.active-line,.interactive-course pre .legacy-line.active-line{background:#2a4334;border-left-color:#8cd8ad}.interactive-course pre.player-output{color:#cbdcd0}.interactive-course pre .legacy-output-line.revealed{color:#e1eae4}
/* Preserve the fixed 728 × 90 ad without overflowing narrower lesson areas. */
.lesson-workspace{background:var(--lesson-surface);min-width:0;align-self:start;container-type:inline-size}.lesson-top-ad{width:728px;height:90px;margin:0 auto;text-align:center;line-height:0}@container(max-width:727px){.lesson-top-ad{display:none}}
/* View choice belongs to the lesson heading. */
.lesson-heading{display:block;margin-bottom:30px}
.lesson-heading h1{margin:0;min-width:0}
.lesson-heading-controls{align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px;margin-top:18px}
.lesson-heading .section-current{margin:0;font-size:var(--text-label);line-height:1.5;white-space:nowrap;font-variant-numeric:tabular-nums;color:var(--muted)}
@media(max-width:650px){.lesson-heading{margin-bottom:26px}.lesson-heading-controls{gap:10px;margin-top:16px}.lesson-heading .section-current{margin-left:auto}}
/* Quiz cards keep the question, choice and feedback easy to scan. */
.lesson-quiz fieldset{min-width:0}.lesson-quiz legend{font-size:var(--text-heading);line-height:1.4;letter-spacing:-.02em;font-weight:650;margin-bottom:24px;width:100%}.lesson-quiz .quiz-option{position:relative;align-items:center;gap:14px;padding:15px 18px;margin-bottom:12px;border-radius:13px;border:1px solid var(--border);background:var(--panel);transition:border-color 150ms ease,background 150ms ease}.lesson-quiz .quiz-option:hover{border-color:var(--accent);background:var(--accent-soft)}.quiz-option>input{position:absolute;opacity:0;width:1px;height:1px;margin:0}.quiz-choice-marker{display:grid;place-items:center;width:30px;height:30px;flex:0 0 30px;border-radius:9px;background:var(--code);border:1px solid var(--border);font-size:var(--text-label);font-weight:650;color:var(--muted);line-height:1}.quiz-choice-text{font-size:var(--text-body);line-height:var(--leading-body);min-width:0;white-space:pre-wrap}.quiz-option:has(input:checked){border-color:var(--accent);background:var(--accent-soft)}.quiz-option:has(input:checked) .quiz-choice-marker{background:var(--accent);border-color:var(--accent);color:var(--panel)}.quiz-option:has(input:focus-visible){outline:3px solid var(--focus);outline-offset:3px}.quiz-actions{display:flex;align-items:center;gap:16px;flex-wrap:wrap;margin-top:24px}.quiz-actions .check-answer{margin:0;padding:11px 20px;border-radius:10px;font-size:var(--text-label);box-shadow:0 2px 4px #00000008}.quiz-hint{font-size:var(--text-label);color:var(--muted)}.quiz-feedback{margin:20px 0 0;padding:16px 18px;border-radius:12px;background:var(--code);font-size:var(--text-body);line-height:var(--leading-body)}.quiz-feedback:empty{display:none}.quiz-feedback.correct{background:var(--accent-soft);color:var(--correct)}.quiz-feedback.retry{background:color-mix(in srgb,var(--incorrect) 9%,var(--panel));color:var(--incorrect)}.quiz-option.answer-retry{border-color:var(--incorrect)}.quiz-option.answer-retry .quiz-choice-marker{background:var(--incorrect);border-color:var(--incorrect);color:var(--panel)}@media(max-width:650px){.lesson-quiz .quiz-option{gap:11px;padding:13px 12px}.quiz-choice-text{font-size:var(--text-body)}.quiz-actions{gap:10px;margin-top:20px}.quiz-hint{font-size:var(--text-label)}}@media(prefers-reduced-motion:reduce){.lesson-quiz .quiz-option{transition:none}}
.quiz-actions .check-answer:hover{background:var(--accent);color:var(--panel);filter:brightness(.94)}
/* Quiz states: blue selection, green success, red retry. */
.interactive-course{--quiz-selected-bg:#edf4ff;--quiz-selected-border:#477ac2;--quiz-selected-ink:#24578f;--quiz-correct-bg:#e9f5ec;--quiz-correct-border:#438458;--quiz-correct-ink:#24613b;--quiz-wrong-bg:#fff0ee;--quiz-wrong-border:#be6558;--quiz-wrong-ink:#9a3e31}:root[data-theme=dark] .interactive-course{--quiz-selected-bg:#203448;--quiz-selected-border:#7fb3ed;--quiz-selected-ink:#b6d6ff;--quiz-correct-bg:#213c2c;--quiz-correct-border:#79bf8d;--quiz-correct-ink:#b0e4bc;--quiz-wrong-bg:#452b28;--quiz-wrong-border:#e39386;--quiz-wrong-ink:#ffc1b6}.lesson-quiz .quiz-option:has(input:checked){background:var(--quiz-selected-bg);border-color:var(--quiz-selected-border)}.lesson-quiz .quiz-option:has(input:checked) .quiz-choice-marker{background:var(--quiz-selected-border);border-color:var(--quiz-selected-border);color:var(--panel)}.lesson-quiz .quiz-option.answer-correct:has(input:checked){background:var(--quiz-correct-bg);border-color:var(--quiz-correct-border)}.lesson-quiz .quiz-option.answer-correct:has(input:checked) .quiz-choice-marker{background:var(--quiz-correct-border);border-color:var(--quiz-correct-border);color:var(--panel)}.lesson-quiz .quiz-option.answer-retry:has(input:checked){background:var(--quiz-wrong-bg);border-color:var(--quiz-wrong-border)}.lesson-quiz .quiz-option.answer-retry:has(input:checked) .quiz-choice-marker{background:var(--quiz-wrong-border);border-color:var(--quiz-wrong-border);color:var(--panel)}.lesson-quiz .quiz-feedback.correct{background:var(--quiz-correct-bg);color:var(--quiz-correct-ink)}.lesson-quiz .quiz-feedback.retry{background:var(--quiz-wrong-bg);color:var(--quiz-wrong-ink)}
/* Give the quiz question breathing room after its code example. */
.lesson-section .section-prose:has(+ .lesson-quiz){margin-bottom:28px}.lesson-section .section-prose:has(+ .lesson-quiz)>pre:last-child{margin-bottom:0}.lesson-quiz legend{padding:0 0 4px}@media(max-width:650px){.lesson-section .section-prose:has(+ .lesson-quiz){margin-bottom:24px}}
/* Short readings are focused fact cards, with their content immediately visible. */
.lesson-section.short-reading{max-width:780px;padding:28px 30px;border-radius:16px}.short-reading>h2{font-size:var(--text-heading);line-height:1.3;margin-bottom:20px}.short-reading .section-prose{font-size:var(--text-body);line-height:var(--leading-body);max-width:62ch}.short-reading .section-prose>p:last-child,.short-reading .section-prose>ul:last-child,.short-reading .section-prose>ol:last-child{margin-bottom:0}.short-reading .reading-key-fact{font-size:var(--text-subheading);line-height:1.25;font-weight:700;letter-spacing:-.025em;color:var(--accent);margin-bottom:16px}.short-reading .section-prose ul{list-style:none;padding:0;margin-top:0}.short-reading .section-prose ul>li{position:relative;padding:10px 0 10px 22px;border-bottom:1px solid var(--border)}.short-reading .section-prose ul>li:last-child{border:0}.short-reading .section-prose ul>li::before{content:'';position:absolute;width:6px;height:6px;left:1px;top:23px;background:var(--accent);border-radius:50%}.reading-timeline{display:grid;grid-template-columns:1fr 1fr;list-style:none;padding:0;margin:24px 0 0;gap:0}.reading-timeline li{position:relative;border-top:2px solid var(--border);padding:18px 14px 0 0;display:flex;flex-direction:column;gap:4px}.reading-timeline li::before{content:'';position:absolute;top:-5px;left:0;width:8px;height:8px;border-radius:50%;background:var(--accent)}.reading-timeline strong{font-size:var(--text-subheading);color:var(--text)}.reading-timeline span{font-size:var(--text-body);color:var(--muted)}@media(max-width:650px){.lesson-section.short-reading{padding:23px 20px}.short-reading>h2{font-size:var(--text-heading)}.short-reading .section-prose{font-size:var(--text-body)}}

/* Compact course index: one lesson per row with aligned, labelled statistics. */
.catalog-heading{display:flex;align-items:flex-end;justify-content:space-between;gap:20px;margin-bottom:16px}
.catalog-heading h2{margin:0}.catalog-eyebrow{margin:0 0 8px;color:var(--accent);font-size:12px;font-weight:700;letter-spacing:.1em;text-transform:uppercase}
.catalog-totals{display:flex;flex-wrap:wrap;gap:8px 18px;color:var(--muted);font-size:14px}.catalog-estimate{max-width:700px;font-size:14px;color:var(--muted);margin:0 0 24px}.course-catalog .course-progress{margin-bottom:8px}
.course-catalog .catalog-group{padding:0;overflow:hidden;margin:20px 0;border-radius:16px}
.catalog-group-heading{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:20px 22px;background:var(--accent-soft)}
.catalog-group-heading h3{margin:0;font-size:18px}.catalog-group-heading>span{font-size:13px;color:var(--muted);white-space:nowrap}
.catalog-columns,.course-catalog .catalog-row{display:grid;grid-template-columns:minmax(0,1fr) 90px 90px 100px 20px;align-items:center;gap:16px;padding:12px 22px}
.catalog-columns{color:var(--muted);font-size:12px;font-weight:600;border-bottom:1px solid var(--border)}.catalog-columns>span:not(:first-child){text-align:center}
.course-catalog .catalog-group ol{display:block;list-style:none;padding:0;margin:0}.course-catalog .catalog-group li+li{border-top:1px solid var(--border)}
.course-catalog .catalog-row{min-height:62px;text-decoration:none;color:var(--text);transition:background .15s}.course-catalog .catalog-row:hover{background:var(--accent-soft)}.course-catalog .catalog-row:focus-visible{outline-offset:-3px}
.catalog-lesson{display:flex;align-items:center;gap:14px;min-width:0}.catalog-number{display:grid;place-items:center;width:28px;height:28px;flex-shrink:0;border-radius:50%;background:var(--code);color:var(--muted);font-size:11px;font-variant-numeric:tabular-nums}.catalog-title{font-size:15px;font-weight:600;overflow-wrap:anywhere}.catalog-row .lesson-status{color:var(--correct);font-size:14px;flex-shrink:0}
.catalog-stat{text-align:center;font-size:14px;color:var(--muted);font-variant-numeric:tabular-nums}.catalog-arrow{color:var(--accent);text-align:right}.catalog-mobile-icon{display:none}.catalog-icon{width:16px;height:16px;flex-shrink:0;vertical-align:middle}.catalog-column-label{display:flex;align-items:center;justify-content:center;gap:6px;white-space:nowrap}
@media(max-width:700px){.catalog-heading{align-items:flex-start;flex-direction:column;gap:14px}.catalog-group-heading{padding:16px;align-items:flex-start}.catalog-group-heading h3{font-size:16px}.catalog-group-heading>span{font-size:12px}.catalog-columns{grid-template-columns:minmax(0,1fr) 28px 28px 28px 20px;padding:9px 16px;gap:14px}.catalog-heading-text{display:none}.course-catalog .catalog-row{grid-template-columns:repeat(3,max-content) minmax(0,1fr);gap:6px 14px;padding:12px 16px}.catalog-lesson{grid-column:1 / -1;grid-row:1;gap:10px;padding-right:22px}.catalog-stat{grid-row:2;text-align:left;font-size:12px}.catalog-lesson+.catalog-stat{margin-left:36px}.catalog-arrow{grid-column:4;grid-row:1}.catalog-stat{display:inline-flex;align-items:center;gap:5px}.catalog-mobile-icon{display:inline-flex}.catalog-mobile-icon .catalog-icon{width:14px;height:14px}.catalog-number{width:26px;height:26px}.catalog-title{font-size:14px}.catalog-group-heading{gap:10px}}
@media(prefers-reduced-motion:reduce){.course-catalog .catalog-row{transition:none}}

.reference-library-link{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:22px 24px;margin-top:28px;border:1px solid var(--border);border-radius:14px;background:var(--accent-soft);text-decoration:none}.reference-library-link strong{display:block;font-size:18px;margin-bottom:5px}.reference-library-link div>span{display:block;color:var(--muted);font-size:14px}.reference-library-heading{max-width:760px;margin-bottom:36px}.reference-library-heading>a{display:inline-block;margin-bottom:28px;font-size:14px}.reference-library-heading>p:last-child{color:var(--muted)}.reference-group{border:1px solid var(--border);border-radius:16px;overflow:hidden;background:var(--panel);margin-bottom:28px}.reference-group h2{font-size:20px;margin:0}.reference-list{list-style:none;margin:0;padding:0}.reference-list li+li{border-top:1px solid var(--border)}.reference-list a{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:16px 22px;text-decoration:none}.reference-list a:hover{background:var(--accent-soft)}.reference-list p{font-size:14px;line-height:1.5;color:var(--muted);margin:5px 0 0}.reference-list strong{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:15px}.reference-sidebar{padding:12px 0 20px;border-bottom:1px solid var(--border);margin-bottom:16px}.reference-sidebar>a{font-size:13px}.reference-sidebar>p{margin:12px 0;font-weight:650}.reference-page-label{font-size:14px;display:inline-block;margin-bottom:12px}@media(max-width:650px){.reference-library-link{padding:18px}.reference-list a{padding:14px 16px}.reference-group h2{font-size:18px}.reference-library-heading h1{font-size:30px}}

/* Put the learning path directly below a compact, optional introduction. */
.course-home:has(.home-hero){padding-top:32px}.home-hero{max-width:none;text-align:left;margin:0 0 28px}.home-hero h1{font-size:clamp(30px,3.5vw,42px);line-height:1.15;margin:0 0 12px}.home-hero>p{font-size:16px;margin-bottom:16px}.home-hero .course-breadcrumb{font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.1em;color:var(--accent);margin:0 0 10px}.home-actions{display:flex;flex-direction:column;align-items:flex-start;gap:12px}.browse-lessons{font-size:14px;font-weight:600;text-decoration:none;padding:10px 0}.browse-lessons:hover{text-decoration:underline}.home-hero .home-note{font-size:12px;margin:12px 0 0}.home-hero .home-preview{padding:0;margin:16px 0 0;border-radius:12px}.home-preview-body{padding:8px 20px 20px;text-align:left}.home-preview-body>p{font-size:14px;color:var(--muted);margin-bottom:16px}.course-catalog{scroll-margin-top:calc(var(--header-height) + 20px)}@media(max-width:650px){.course-home:has(.home-hero){padding-top:24px}.home-hero>p{font-size:15px}.home-preview-body{padding:6px 12px 16px}}

.catalog-search{align-items:center;gap:10px;position:relative;width:100%;margin:0 0 8px}.catalog-search svg{position:absolute;left:14px;width:18px;height:18px;color:var(--muted);pointer-events:none}.catalog-search input{width:100%;min-width:0;min-height:48px;padding:11px 14px 11px 42px;border:1px solid var(--border);border-radius:10px;background:var(--panel);color:var(--text);font-size:14px}.catalog-search input::placeholder{color:var(--muted);opacity:1}.catalog-search-status{font-size:14px;color:var(--muted);margin:0 0 16px}.catalog-empty{padding:24px;border:1px dashed var(--border);border-radius:12px;color:var(--muted)}@media(max-width:650px){.home-actions{gap:12px}.catalog-search{min-width:0}.home-actions .start-learning{padding:12px 16px;font-size:14px}}@media(prefers-reduced-motion:reduce){}

.continue-learning{display:inline-block;padding:12px 22px;border-radius:10px;background:var(--accent);color:var(--panel);font-weight:650;text-decoration:none}.home-actions:has(.continue-learning:not([hidden])) .start-learning{background:var(--panel);color:var(--accent);box-shadow:inset 0 0 0 1px var(--border)}@media(max-width:650px){.continue-learning{padding:12px 16px;font-size:14px}}
.continue-learning{max-width:100%;overflow-wrap:anywhere}.reference-group-meta{display:flex;align-items:center;gap:18px;color:var(--muted);font-size:13px;white-space:nowrap}@media(max-width:650px){.reference-group-meta{gap:12px;font-size:12px}}

/* Lesson content remains visible; navigation groups can collapse independently. */
.lesson-group-heading{margin:0;font-weight:700}.home-preview{margin:28px 0 0;padding:20px;border-radius:12px}.preview-heading{font-size:20px;margin:0 0 16px}.home-preview-body{padding:0}.visual-brief h4{font-size:var(--text-label);margin:0 0 12px}.section-prose .course-content-block{margin:24px 0}.reference-group .catalog-group-heading{cursor:default}

/* Collapsible sidebar groups: keep every destination visible without JavaScript. */
.lesson-group-heading{padding:0}
.lesson-group-toggle{display:flex;align-items:center;gap:10px;width:100%;padding:12px 8px;border:0;border-radius:8px;background:transparent;color:var(--muted);font-size:12px;font-weight:700;line-height:1.5;text-align:left;letter-spacing:.01em}
.lesson-group-toggle>span:first-child{flex:1;min-width:0}
.lesson-group-toggle:disabled{opacity:1;cursor:default}
.group-chevron{width:7px;height:7px;border-right:1.5px solid currentColor;border-bottom:1.5px solid currentColor;transform:rotate(45deg);margin:0 4px 4px;transition:transform 220ms ease}
.group-collapsible .group-chevron{transform:rotate(-45deg);margin-bottom:0}
.group-open .group-chevron{transform:rotate(45deg)}
.lesson-group-panel{display:grid;grid-template-rows:1fr}
.lesson-group-content{min-height:0}
.group-collapsible .lesson-group-panel{grid-template-rows:0fr;transition:grid-template-rows 220ms ease}
.group-collapsible .lesson-group-content{overflow:hidden}
.group-open .lesson-group-panel{grid-template-rows:1fr}
.group-open .lesson-group-toggle{color:var(--text)}
@media(prefers-reduced-motion:reduce){.group-chevron,.group-collapsible .lesson-group-panel{transition:none}}

/* Site navigation and footer share the course theme. */
.lesson-section>.lesson-code-context+.section-prose{margin-top:24px}
.header-nav-menu>summary{display:flex;align-items:center;gap:6px;list-style:none;padding:10px 8px;border-radius:8px;font-weight:650}
.header-nav-menu>summary::-webkit-details-marker{display:none}
.header-site-nav>.header-nav-link{display:flex;align-items:center;padding:10px 8px;border-radius:8px;color:var(--text);font-size:inherit;font-weight:650;text-decoration:none;white-space:nowrap}
.header-site-nav>.header-nav-link:hover{background:var(--accent-soft)}
.header-nav-menu>summary:hover,.header-nav-menu[open]>summary{background:var(--accent-soft)}
.header-nav-chevron{display:inline-grid;place-items:center;flex:0 0 18px;width:18px;height:18px;margin-left:2px;transition:transform 250ms ease-in-out}.header-nav-chevron svg{display:block;width:18px;height:18px}
.header-nav-menu[open] .header-nav-chevron{transform:rotate(180deg)}
.header-dropdown-panel{max-height:calc(100dvh - var(--header-height) - 20px);overflow:auto;overscroll-behavior:contain;gap:22px;padding:22px;z-index:15}
.header-dropdown-heading{color:var(--muted);font-size:12px;margin-bottom:5px}
.header-dropdown-panel a{padding:5px 0;line-height:1.5}
.header-dropdown-panel a:hover{text-decoration:underline}
.interactive-course .site-footer{margin-top:36px;padding:32px 0 24px}
.interactive-course .footer-main{display:grid;grid-template-columns:minmax(180px,.8fr) minmax(0,2fr);gap:40px}
.interactive-course .footer-brand p{font-size:14px;line-height:1.7;margin:12px 0 0}
.interactive-course .footer-logo{text-decoration:none;color:var(--text);letter-spacing:-.03em}
.interactive-course .footer-links{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:24px}
.interactive-course .footer-column{gap:9px;min-width:0}
.interactive-course .footer-column h2{color:var(--text);font-size:13px;letter-spacing:0;margin:0 0 5px}
.interactive-course .footer-column a{font-size:13px;text-decoration:none;line-height:1.5;color:var(--muted)}
.interactive-course .footer-column a:hover,.interactive-course .footer-legal a:hover{color:var(--accent);text-decoration:underline}
.interactive-course .footer-bottom{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-top:30px;padding-top:20px;border-top:1px solid var(--border)}
.interactive-course .footer-legal{display:flex;flex-wrap:wrap;gap:12px 20px}
.interactive-course .footer-legal a{color:var(--muted);text-decoration:none;font-size:12px}
.interactive-course .copyright{font-size:12px;margin:0}
@media(max-width:900px){.interactive-course .footer-main{grid-template-columns:1fr;gap:24px}.interactive-course .footer-brand{max-width:480px}}
@media(max-width:650px){
  :root{--header-height:104px}
  .interactive-course header{height:var(--header-height);flex-wrap:wrap;gap:0;padding:10px 14px 0}
  .interactive-course .header-left,.interactive-course .header-right{height:44px}
  .interactive-course .header-right{margin-left:auto}
  .interactive-course .header-site-nav{display:flex;order:3;flex-basis:100%;align-items:center;justify-content:center;gap:8px;height:40px;font-size:13px}
  .interactive-course .header-nav-menu>summary,.interactive-course .header-nav-link{padding:8px 6px}
  .interactive-course .header-dropdown-panel{top:var(--header-height);left:10px;right:10px;width:auto;max-width:none;padding:20px;gap:20px}
  .interactive-course .footer-links{grid-template-columns:repeat(2,minmax(0,1fr));gap:26px 20px}
  .interactive-course .site-footer{margin-top:28px;padding-top:24px}
  .interactive-course .footer-bottom{align-items:flex-start;flex-direction:column}
}
@media(prefers-reduced-motion:reduce){.header-nav-chevron{transition:none}}

/* Shared lesson views: controls stay outside the scrolling lesson groups. */
.lesson-view-switch{display:flex;flex-shrink:0;margin:0;padding:4px;gap:3px;border:1px solid var(--border);border-radius:12px;background:var(--bg)}
.lesson-view-switch button{flex:1;padding:9px 12px;border:0;border-radius:8px;font-size:12px;font-weight:650;white-space:nowrap;background:transparent;color:var(--muted)}
.lesson-view-switch button[aria-pressed=true]{background:var(--panel);color:var(--accent);box-shadow:0 1px 4px #0001}
.section-read-button.js-control,.enhanced .full-lesson-navigation{display:none}
.full-lesson-navigation{display:flex;flex-wrap:wrap;justify-content:space-between;gap:20px;margin-top:28px;padding:24px 0;border-top:1px solid var(--border)}
.enhanced[data-lesson-view=full] .section-read-button{display:inline-flex;margin-top:22px;align-items:center;gap:8px;font-size:var(--text-label)}
.enhanced[data-lesson-view=full] .section-current,.enhanced[data-lesson-view=full] [data-section-counter],.enhanced[data-lesson-view=full] .recap-status~.next-lesson{display:none}
.enhanced[data-lesson-view=full] .full-lesson-navigation a{font-weight:650}
.enhanced[data-lesson-view=full] .lesson-section{scroll-margin-top:calc(var(--header-height) + 24px);margin-bottom:28px}
.enhanced[data-lesson-view=full] .lesson-main{padding-bottom:calc(var(--lesson-nav-height,78px) + 36px)}

/* Course explorer: lessons above, progress anchored below the scrolling tree. */
:root{--sidebar-surface:#f6f4f0}
:root[data-theme=dark]{--sidebar-surface:#18211c}
.course-sidebar{background:var(--sidebar-surface)}
.sidebar-heading,.lesson-view-switch,.sidebar-progress{flex-shrink:0}
.sidebar-lessons{margin-top:18px;padding-bottom:12px}
.sidebar-folder-icon,.sidebar-lesson-icon{width:18px;height:18px;flex:0 0 18px;color:var(--muted)}
.sidebar-folder-icon{color:var(--accent)}
.lesson-group-toggle{gap:9px;padding:11px 8px;font-size:12px}
.lesson-group-toggle>.group-name{flex:1;min-width:0}
.lesson-group-toggle>.group-count{background:transparent;padding:0;min-width:16px}
.lesson-group ol>li::before,.lesson-group ol>li::after{display:none}
.lesson-group a[data-lesson-link]{position:relative;gap:9px;padding:10px 10px 10px 14px;min-height:42px;border-radius:8px;font-size:13px}
.lesson-group a[aria-current=page]{background:var(--accent-soft);color:var(--text);font-weight:650}
.lesson-group a[aria-current=page]::before{content:'';position:absolute;inset:9px auto 9px 0;width:3px;border-radius:4px;background:var(--accent)}
.lesson-group a[aria-current=page] .sidebar-lesson-icon,.lesson-group a.is-complete .sidebar-lesson-icon{color:var(--accent)}
.course-sidebar .lesson-status{display:grid;place-items:center;flex:0 0 16px;width:16px;height:16px;margin-left:auto;font-size:11px;line-height:1}
.course-sidebar .lesson-status:empty{visibility:hidden;display:grid}
.course-sidebar .is-complete .lesson-status{border-radius:50%;background:var(--path-complete);color:var(--accent)}
.course-sidebar .section-map{margin:7px 0 14px 23px;padding:0 0 0 12px;border-left:1px solid var(--border)}
.course-sidebar .section-link{padding:8px 6px;gap:9px;min-height:38px}
.course-sidebar .section-link::before,.course-sidebar .section-link::after{display:none}
.course-sidebar .section-number{width:20px;height:20px;min-width:20px;font-size:10px}
.course-sidebar .section-link[aria-current=step]>.section-number::after{animation:none;opacity:.25;inset:-3px}
.course-sidebar .compiler-link{padding:12px 4px;border-top:0}
.sidebar-progress{margin-top:auto;padding:18px 10px 0;border-top:1px solid var(--border)}
.sidebar-progress-heading{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:12px;font-size:12px;font-weight:650;color:var(--text)}
.sidebar-progress-heading strong{font-size:12px;color:var(--accent);font-variant-numeric:tabular-nums}
.sidebar-progress .course-progress{margin:10px 0 0;font-size:11px;color:var(--muted);line-height:1.5}
@media(max-width:650px){.enhanced .course-sidebar{background:var(--sidebar-surface)}.sidebar-lessons{margin-top:16px}.sidebar-progress{padding-top:15px}}

/* A single surface frames the lesson; search leaves group expansion untouched. */
.interactive-course .header-container,.interactive-course .lesson-controls{background-color:var(--sidebar-surface);background-image:none}
.lesson-controls span{background:transparent}
.sidebar-heading{gap:8px}
.sidebar-heading-copy{min-width:0;flex:1;display:flex;flex-direction:column;gap:4px}
.sidebar-heading-copy>a{font-size:17px;line-height:1.35;color:var(--text);text-decoration:none}
.sidebar-heading-copy>span{font-size:10px;letter-spacing:.07em;text-transform:uppercase;color:var(--muted);font-weight:500}
.enhanced .course-sidebar .drawer-close{display:flex!important;align-items:center;justify-content:center;width:30px;height:32px;flex:0 0 30px;padding:5px;background:transparent;border-radius:7px}
.drawer-close svg{width:19px;height:19px}
.sidebar-search{flex-shrink:0;align-items:center;gap:7px;margin:16px 8px 0;padding:9px 10px;border:1px solid var(--border);border-radius:10px;background:var(--lesson-surface);color:var(--muted)}
.sidebar-search:focus-within{outline:2px solid var(--focus);outline-offset:2px}
.sidebar-search>svg{width:16px;height:16px;flex:0 0 16px}
.sidebar-search input{min-width:0;width:100%;padding:0;border:0;background:transparent;color:var(--text);font-size:12px;outline:none}
.sidebar-search input:focus-visible{outline:none}
.sidebar-search input::placeholder{color:var(--muted);opacity:1}
.sidebar-search kbd{flex-shrink:0;font:10px var(--font-text);white-space:nowrap}
.sidebar-search-status{margin:0;padding:4px 10px 12px;font-size:12px;color:var(--muted)}
.sidebar-search-result{padding:0 5px 12px}
.sidebar-search-result a{display:block;padding:8px;border-radius:7px;text-decoration:none;font-size:13px;line-height:1.5;color:var(--text)}
.sidebar-search-result a:hover{background:var(--accent-soft)}
.sidebar-search-result .search-lesson-link{font-weight:650;color:var(--accent)}
.sidebar-search-result .search-section-link{margin-left:8px;padding-left:12px;border-left:1px solid var(--border);border-radius:0;font-size:12px;color:var(--muted)}
@media(min-width:651px){
  .enhanced .leftnav-toggle-button{display:none}
  .enhanced.sidebar-hidden{--sidebar-width:52px}
  .enhanced.sidebar-hidden .course-shell{grid-template-columns:var(--sidebar-width) minmax(0,1fr)}
  .enhanced.sidebar-hidden .course-sidebar{display:flex;padding:26px 6px 18px;overflow:hidden}
  .enhanced.sidebar-hidden .course-sidebar>:not(.sidebar-heading),.enhanced.sidebar-hidden .sidebar-heading-copy{display:none}
  .enhanced.sidebar-hidden .sidebar-heading{padding:0;justify-content:center}
  .enhanced.sidebar-hidden .drawer-close svg{transform:scaleX(-1)}
}
@media(max-width:650px){.sidebar-search{margin-top:14px}.sidebar-search input{font-size:16px}.sidebar-search kbd{display:none}}

/* The three course categories share one row on desktop. */
@media(min-width:651px){
  .header-courses-panel{width:min(620px,calc(100vw - 40px));max-width:none;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px}
}
@media(min-width:651px) and (max-width:1000px){
  .header-courses-panel{position:fixed;top:var(--header-height);right:20px}
}

/* Count the header border inside its height, so viewport-height lessons fit exactly. */
.interactive-course .header-container{height:var(--header-height)}
.interactive-course header{height:calc(var(--header-height) - 1px)}

/* Header catalog panels grow in document flow instead of covering the lesson. */
.interactive-course{overflow-anchor:none}
.header-expansions{position:sticky;top:var(--header-height);z-index:9;background:#18251f;color:#dcebe1;color-scheme:dark;--focus:#9cdbb6;overflow-anchor:none}
.header-expansions .header-dropdown-heading{color:#a9c6b4}
.header-expansions .header-dropdown-panel a{color:#dcebe1;border-radius:6px}
.header-expansions .header-dropdown-panel a:hover{color:#b7f0cc;background:#263c30}
.header-expansions .header-dropdown-panel a:focus-visible{color:#b7f0cc;background:#263c30}
.header-expansion{display:grid;grid-template-rows:0fr;visibility:hidden;transition:grid-template-rows 250ms ease-in-out,visibility 250ms;overflow-anchor:none}
.header-expansion.is-open{grid-template-rows:1fr;visibility:visible}
.header-expansion-body{min-height:0;max-height:calc(100dvh - var(--header-height) - 100px);overflow:auto;overscroll-behavior:contain}
.interactive-course .header-expansions .header-dropdown-panel{position:static;inset:auto;width:calc(100% - 40px);max-width:840px;max-height:none;margin:0 auto;display:grid;padding:24px 28px 30px;gap:24px;border:0;border-radius:0;box-shadow:none;background:transparent;overflow:visible;transform:none}
.header-expansions .header-courses-panel{grid-template-columns:repeat(3,minmax(0,1fr))}
.interactive-course .header-expansions .header-compilers-panel{max-width:600px;grid-template-columns:repeat(2,minmax(0,1fr))}
@media(max-width:650px){
  .interactive-course .header-expansions .header-dropdown-panel{width:calc(100% - 24px);padding:20px 8px 24px;gap:20px}
  .header-expansions .header-courses-panel{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(prefers-reduced-motion:reduce){.header-expansion{transition:none}}

/* Learning paths change the guided route, while the complete menu remains available. */
.lesson-controls{flex-direction:column;align-items:stretch}
.lesson-controls-row{display:flex;align-items:center;justify-content:space-between;gap:12px;width:100%}
.lesson-controls.has-learning-paths .lesson-controls-row{display:grid;grid-template-columns:auto minmax(32px,1fr) auto auto}
.lesson-controls.has-learning-paths [data-section-counter]{text-align:center}
.lesson-controls.has-learning-paths [data-continue]{max-width:240px;white-space:normal}
.learning-paths{margin:0 0 28px;padding:24px;border:1px solid var(--border);border-radius:16px;background:var(--panel)}
.enhanced .home-path-picker{display:block}
.learning-paths .home-note{font-size:12px;color:var(--muted);margin:14px 0 0}
.learning-paths .home-actions{margin-top:18px}
.enhanced .home-path-launch{display:block;margin:20px 0 0;padding-top:18px;border-top:1px solid var(--border)}
.home-path-launch strong{font-size:15px}
.home-path-launch p{font-size:13px;color:var(--muted);margin:6px 0 0}
.learning-paths .home-actions a{max-width:100%;overflow-wrap:anywhere}
.path-recommendation{display:block;font-size:11px;font-weight:500;color:var(--accent);margin-top:5px}
.learning-paths-heading h2{font-size:var(--text-heading);margin:0 0 12px}
.learning-paths-heading p{color:var(--muted);font-size:var(--text-label);margin:0 0 20px}
.learning-path-cards{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:10px}
.path-choice{display:flex;flex-direction:column;align-items:flex-start;gap:8px;padding:16px;text-align:left;background:var(--panel);border:1px solid var(--border);border-radius:12px;color:var(--text)}
.path-choice-title{font-weight:700;font-size:14px}
.path-choice-description,.path-choice-prerequisite,.path-choice small{font-size:12px;line-height:1.5;color:var(--muted)}
.path-choice-prerequisite{font-style:italic}
.path-choice[aria-pressed=true]{border-color:var(--accent);background:var(--accent-soft);box-shadow:inset 0 0 0 1px var(--accent)}
.path-choice[aria-pressed=true] .path-choice-title{color:var(--accent)}
.learning-path-cards>.path-choice{padding:14px;gap:7px;position:relative}
.learning-path-cards>.path-choice small{margin-top:auto;padding-top:4px}
.learning-path-cards>.path-choice[aria-pressed=true]::after{content:'✓';position:absolute;right:10px;bottom:12px;font-size:12px;color:var(--accent)}
.learning-path-cards>.path-choice[aria-pressed=true] small{padding-right:16px}
@media(min-width:1100px){.enhanced .learning-paths{display:grid;grid-template-columns:minmax(0,1fr) auto;column-gap:20px}.learning-paths .home-path-picker,.learning-paths .home-note{grid-column:1/-1}.enhanced .home-path-launch{border:0;padding:0;align-self:center}.learning-paths .home-actions{align-self:center}}
.learning-path-bar{align-items:center;justify-content:center;position:relative;min-width:0}
.path-switcher{position:relative;flex-shrink:0}
.path-switcher>summary{display:flex;align-items:center;gap:8px;list-style:none;font-size:12px;cursor:pointer;padding:7px 11px;border:1px solid var(--border);border-radius:9px;background:var(--panel)}
.path-switcher>summary::-webkit-details-marker{display:none}
.path-switcher>summary strong{font-weight:650}
.path-switcher>summary svg{transition:transform 160ms ease}
.path-switcher[open]>summary svg{transform:rotate(180deg)}
.lesson-controls .path-label{font-size:11px;color:var(--muted);padding:0}
.path-options{position:absolute;bottom:calc(100% + 10px);left:50%;transform:translateX(-50%);width:min(410px,calc(100vw - 28px));max-height:calc(100dvh - var(--header-height) - var(--lesson-nav-height) - 24px);overflow:auto;overscroll-behavior:contain;padding:8px;display:grid;gap:8px;border:1px solid var(--border);border-radius:14px;background:var(--panel);box-shadow:0 12px 36px #0003}
.lesson-controls .path-choice{padding:12px;width:100%;border-radius:9px;background:var(--panel);color:var(--text);font-weight:400}
.lesson-controls .path-choice[aria-pressed=true]{background:var(--accent-soft)}
.lesson-controls .path-choice span{padding:0;line-height:1.5;background:transparent}
.lesson-controls .path-choice .path-choice-title{color:var(--text)}
.lesson-controls .path-choice[aria-pressed=true] .path-choice-title{color:var(--accent)}
.path-feedback{font-size:12px;line-height:1.5;color:var(--muted);margin:0;max-width:60ch}
.learning-paths>.path-feedback{margin-top:16px}
.path-feedback a{display:inline-block;margin-left:8px;font-weight:650}
.path-options .path-feedback{padding:10px 12px;border-bottom:1px solid var(--border)}
.enhanced[data-lesson-view=full] .lesson-controls.has-learning-paths .lesson-controls-row{grid-template-columns:minmax(0,1fr) auto minmax(0,1fr)}
.enhanced[data-lesson-view=full] .lesson-controls [data-previous]{justify-self:start}
.enhanced[data-lesson-view=full] .lesson-controls [data-continue]{justify-self:end}
body.has-learning-paths .lesson-main{padding-bottom:calc(var(--lesson-nav-height,78px) + 36px)}
@media(max-width:1100px){.learning-path-cards{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:650px){.learning-path-cards{grid-template-columns:1fr}.learning-path-cards>.path-choice{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:5px 12px;padding:12px}.learning-path-cards .path-choice-title{grid-column:1}.learning-path-cards .path-choice-description,.learning-path-cards .path-choice-prerequisite{grid-column:1/-1}.learning-path-cards .path-choice small{grid-column:2;grid-row:1;align-self:start;margin:0;padding-top:0}.learning-path-cards .path-recommendation{grid-column:1/-1;margin:0}.learning-path-cards>.path-choice[aria-pressed=true]::after{bottom:auto;top:12px}.learning-path-cards .path-choice-prerequisite{font-size:11px}}
@media(max-width:650px){
  .enhanced .learning-paths{padding:18px;margin-bottom:24px}
  .path-feedback{font-size:11px;text-align:center;max-width:none}
  .lesson-controls-row{gap:8px}
  .lesson-controls-row [data-continue]{max-width:55%;white-space:normal}
}
@media(max-width:800px){
  .lesson-controls.has-learning-paths .lesson-controls-row{grid-template-columns:minmax(0,1fr) auto minmax(0,1fr);gap:8px}
  .lesson-controls.has-learning-paths .learning-path-bar{grid-column:1/-1;grid-row:1;align-items:stretch}
  .lesson-controls.has-learning-paths .path-switcher{width:100%}
  .lesson-controls.has-learning-paths [data-previous]{justify-self:start}
  .lesson-controls.has-learning-paths [data-continue]{justify-self:end;max-width:100%;font-size:12px;padding:9px 12px}
  .path-switcher>summary{justify-content:center}
  .path-options{left:0;transform:none;width:100%}
  .enhanced[data-lesson-view=full] .lesson-controls.has-learning-paths .learning-path-bar{width:100%}
  .enhanced[data-lesson-view=full] .lesson-controls.has-learning-paths [data-continue]{grid-column:3}
}
@media(prefers-reduced-motion:reduce){.path-switcher>summary svg{transition:none}}

/* Distraction-free reading; the visualization's fullscreen is independent. */
.lesson-focus-toggle{display:inline-flex;align-items:center;justify-content:center;flex:0 0 40px;width:40px;height:40px;padding:0}
.lesson-focus-restore{position:fixed;top:max(12px,env(safe-area-inset-top));right:max(16px,env(safe-area-inset-right));z-index:30;display:flex;align-items:center;gap:7px;min-height:44px;padding:10px 12px;font-size:12px;box-shadow:0 3px 12px #0001}
body.lesson-focus-mode{--sidebar-width:0px;--header-height:0px}
body.lesson-focus-mode :is(.header-container,.header-expansions,.course-sidebar,.drawer-overlay,.lesson-top-ad){display:none!important}
body.lesson-focus-mode .course-shell{grid-template-columns:minmax(0,1fr)!important}
body.lesson-focus-mode .lesson-controls{left:0;right:0}
body.lesson-focus-mode .lesson-heading{padding-right:100px}
body.lesson-focus-mode .lesson-section{scroll-margin-top:20px}
body.lesson-focus-mode.has-player-fullscreen .lesson-focus-restore{visibility:hidden}
@media(max-width:650px){body.lesson-focus-mode .lesson-heading{padding-right:0}body.lesson-focus-mode .lesson-main{padding-top:68px}.lesson-focus-toggle{min-width:44px;min-height:44px}.lesson-focus-restore{right:12px}}
.lesson-heading-controls{justify-content:flex-start}.lesson-heading-controls .section-current{margin-left:auto}

/* Illustrated choices on course corner pages; lesson dropdowns stay compact. */
.course-home .learning-paths{padding:24px;background:var(--panel);border-radius:20px}
.learning-path-cards{gap:14px}
.learning-path-cards>.path-choice{--path-color:#3971bd;--path-wash:#edf4ff;display:flex;padding:18px;gap:10px;border-radius:16px;transition:border-color 160ms ease,box-shadow 160ms ease;background:var(--panel);min-width:0;overflow:hidden}
.learning-path-cards>.path-choice:nth-child(2){--path-color:#278765;--path-wash:#eaf7f0}
.learning-path-cards>.path-choice:nth-child(3){--path-color:#8354bd;--path-wash:#f4edfc}
.learning-path-cards>[data-path-choice=all]{--path-color:#b87819;--path-wash:#fff5e5}
.learning-path-cards .path-art{display:flex;align-items:center;justify-content:center;width:100%;height:100px;margin-bottom:4px;border-radius:11px;background:var(--path-wash)}
.learning-path-cards .path-art img{display:block;width:64px;height:64px;object-fit:contain}
.learning-path-cards .path-choice-title{font-size:16px;line-height:1.4;color:var(--text)}
.learning-path-cards .path-choice-description{font-size:13px;line-height:1.6}
.learning-path-cards .path-recommendation{margin:0;padding:3px 7px;border-radius:5px;background:var(--path-wash);color:var(--path-color);font-size:10px;font-weight:650}
.learning-path-cards .path-choice-prerequisite{font-style:normal;font-size:11px}
.learning-path-cards>.path-choice small{width:100%;padding-top:12px;margin-top:auto;border-top:1px solid var(--border);font-size:12px;font-weight:600}
.learning-path-cards>.path-choice:hover{border-color:var(--path-color);box-shadow:0 3px 12px #0000000a}
.learning-path-cards>.path-choice[aria-pressed=true]{background:var(--panel);border-color:var(--path-color);box-shadow:inset 0 0 0 1px var(--path-color)}
.learning-path-cards>.path-choice[aria-pressed=true] .path-choice-title{color:var(--path-color)}
.learning-path-cards>.path-choice[aria-pressed=true]::after{top:26px;right:26px;bottom:auto;width:22px;height:22px;display:grid;place-items:center;border-radius:50%;background:var(--path-color);color:#fff;font-weight:700}
:root[data-theme=dark] .learning-path-cards>.path-choice{--path-color:#8cb9f4;--path-wash:#18283e}
:root[data-theme=dark] .learning-path-cards>.path-choice:nth-child(2){--path-color:#83c9aa;--path-wash:#183127}
:root[data-theme=dark] .learning-path-cards>.path-choice:nth-child(3){--path-color:#c2a1eb;--path-wash:#2b203d}
:root[data-theme=dark] .learning-path-cards>[data-path-choice=all]{--path-color:#e9bd76;--path-wash:#362b1a}
:root[data-theme=dark] .learning-path-cards .path-art img{filter:brightness(1.55)}
@media(max-width:650px){
 .course-home .learning-paths{padding:16px}
 .learning-path-cards{gap:10px}
 .learning-path-cards>.path-choice{display:grid;grid-template-columns:60px minmax(0,1fr);gap:5px 12px;padding:14px}
 .learning-path-cards .path-art{grid-column:1;grid-row:1/6;align-self:start;width:60px;height:68px;margin:0;border-radius:9px}
 .learning-path-cards .path-art img{width:42px;height:42px}
 .learning-path-cards .path-choice-title{grid-column:2;grid-row:1;padding-right:20px;font-size:14px}
 .learning-path-cards :is(.path-choice-description,.path-choice-prerequisite,.path-recommendation){grid-column:2}
 .learning-path-cards .path-choice-description{font-size:12px}
 .learning-path-cards>.path-choice small{grid-column:2;grid-row:auto;padding-top:7px;margin-top:4px;font-size:11px}
 .learning-path-cards .path-recommendation{justify-self:start;font-size:9px}
 .learning-path-cards>.path-choice[aria-pressed=true]::after{top:14px;right:14px;width:18px;height:18px;font-size:10px}
}
@media(prefers-reduced-motion:reduce){.learning-path-cards>.path-choice{transition:none}}
:root[data-theme=dark] .learning-path-cards>.path-choice[aria-pressed=true]::after{color:#17251e}

.catalog-group-disclosure>.catalog-group-heading{cursor:pointer;list-style:none}
.catalog-group-actions{justify-content:flex-end;gap:0;margin:12px 0}
.catalog-group-actions button{padding:7px 12px;font-size:13px;line-height:1.4;border-radius:0}
.catalog-group-actions button:first-child{border-radius:8px 0 0 8px}
.catalog-group-actions button:last-child{border-radius:0 8px 8px 0;margin-left:-1px}
.catalog-group-actions button:focus-visible{position:relative;z-index:1}
.catalog-group-disclosure>.catalog-group-heading::-webkit-details-marker{display:none}
.catalog-group-heading>.catalog-group-summary{display:flex;align-items:center;gap:12px}
.catalog-group-chevron{flex:0 0 18px;transition:transform 180ms ease}
.catalog-group-disclosure[open] .catalog-group-chevron{transform:rotate(180deg)}
.catalog-group-disclosure>.catalog-group-heading:hover{background:color-mix(in srgb,var(--accent-soft) 80%,var(--accent) 20%)}
.catalog-group-disclosure>.catalog-group-heading:focus-visible{outline:3px solid var(--focus);outline-offset:-3px}
@media(prefers-reduced-motion:reduce){.catalog-group-chevron{transition:none}}