:root{--bg:#f3f5f1;--surface:#fbfcf8;--surface-2:#e9eee8;--ink:#17211d;--muted:#59645f;--line:#cbd3ce;--accent:#e45f45;--accent-ink:#35130d;--focus:#116e5d;--radius:18px;--radius-sm:10px;--shadow:0 18px 50px rgb(34 54 45/.1);--max:1320px;--header:76px}*,:before,:after{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font-family:"Avenir Next","PingFang TC","Noto Sans TC",system-ui,sans-serif;line-height:1.65}button,input,textarea,select{font:inherit}button,a{-webkit-tap-highlight-color:transparent}a{color:inherit}button{color:inherit}.skip-link{position:fixed;left:16px;top:-80px;z-index:100;padding:10px 16px;background:var(--ink);color:var(--surface)}.skip-link:focus{top:12px}:focus-visible{outline:3px solid var(--focus);outline-offset:3px}.site-header{position:sticky;top:0;z-index:20;height:var(--header);padding:0 max(20px,calc((100vw - var(--max))/2));display:grid;grid-template-columns:auto 1fr auto;align-items:center;gap:36px;background:rgb(243 245 241/.94);border-bottom:1px solid var(--line);backdrop-filter:blur(14px)}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;line-height:1.1}.brand-mark{width:38px;height:38px;display:grid;place-items:center;background:var(--ink);color:var(--surface);border-radius:var(--radius-sm);font-weight:900}.brand strong{display:block;font-size:.92rem}.brand small{display:block;margin-top:4px;color:var(--muted);font-size:.68rem}.site-nav{display:flex;justify-content:center;gap:28px}.site-nav a{text-decoration:none;font-size:.9rem;font-weight:650}.site-nav a[aria-current=page]{color:var(--accent)}.header-progress{display:flex;align-items:center;gap:10px;color:var(--muted);font-size:.8rem}.progress-dots{display:flex;gap:4px}.progress-dot{width:7px;height:7px;border:1px solid var(--muted);border-radius:50%}.progress-dot.done{background:var(--accent);border-color:var(--accent)}.menu-button{display:none;border:1px solid var(--line);background:var(--surface);border-radius:999px;padding:8px 14px}.page-shell{width:min(var(--max),calc(100% - 40px));margin:auto;padding:48px 0 100px}.hero{min-height:calc(100dvh - var(--header) - 24px);display:grid;grid-template-columns:minmax(0,.85fr) minmax(480px,1.15fr);align-items:center;gap:5vw}.kicker{margin:0 0 16px;color:var(--accent);font-size:.78rem;font-weight:800;letter-spacing:.12em;text-transform:uppercase}.hero h1{max-width:760px;margin:0;font-size:clamp(3rem,6.8vw,6.8rem);line-height:.95;letter-spacing:-.06em}.hero h1 span{display:block;color:var(--accent)}.hero .summary{max-width:600px;margin:28px 0;color:var(--muted);font-size:clamp(1rem,1.4vw,1.25rem)}.button-row{display:flex;flex-wrap:wrap;gap:12px}.button{min-height:48px;padding:12px 21px;display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--ink);border-radius:999px;background:var(--ink);color:var(--surface);text-decoration:none;font-weight:750;white-space:nowrap;cursor:pointer}.button.secondary{background:transparent;color:var(--ink)}.button.accent{border-color:var(--accent);background:var(--accent);color:var(--accent-ink)}.button:active{transform:translateY(1px)}.work-preview{position:relative;min-width:0;padding:14px;background:#d7ddd8;border-radius:var(--radius);box-shadow:var(--shadow);transform:rotate(1deg)}.preview-toolbar{height:34px;display:flex;align-items:center;justify-content:space-between;padding:0 8px;color:#59645f;font-size:.7rem}.preview-status{display:flex;align-items:center;gap:7px}.preview-status:before{content:"";width:8px;height:8px;border-radius:50%;background:#498774}.work-preview iframe{width:100%;height:min(610px,68vh);display:block;border:0;border-radius:12px;background:white}.home-stats{margin:10px 0 100px;display:grid;grid-template-columns:1.2fr .8fr 1fr;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden}.home-stat{min-height:150px;padding:26px;display:flex;flex-direction:column;justify-content:space-between;border-right:1px solid var(--line)}.home-stat:last-child{border-right:0}.home-stat strong{font-size:clamp(2.4rem,5vw,4.8rem);line-height:1}.home-stat span{color:var(--muted)}.section-heading{max-width:800px;margin-bottom:42px}.section-heading h1,.section-heading h2{margin:0 0 16px;font-size:clamp(2.5rem,5vw,5rem);line-height:1;letter-spacing:-.055em}.section-heading p{max-width:650px;margin:0;color:var(--muted);font-size:1.08rem}.path-grid{display:grid;grid-template-columns:repeat(12,1fr);gap:18px}.lesson-card{grid-column:span 4;min-height:330px;padding:28px;display:flex;flex-direction:column;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);text-decoration:none}.lesson-card:nth-child(1),.lesson-card:nth-child(5){grid-column:span 7}.lesson-card:nth-child(2),.lesson-card:nth-child(6){grid-column:span 5}.lesson-card:hover{border-color:var(--ink)}.lesson-card .number{font-size:.78rem;font-weight:900}.lesson-card h3{max-width:420px;margin:auto 0 12px;font-size:clamp(1.7rem,3vw,3rem);line-height:1.05;letter-spacing:-.04em}.lesson-card p{margin:0;color:var(--muted)}.lesson-meta{margin-top:24px;display:flex;justify-content:space-between;gap:12px;font-size:.8rem}.lesson-card.completed{background:var(--surface-2)}.lesson-card.completed .number:after{content:" 已完成";color:var(--accent);margin-left:8px}.coral{--card:#f3b3a6}.blue{--card:#b9d8e7}.lime{--card:#cde59d}.yellow{--card:#ead589}.violet{--card:#cbbfe4}.teal{--card:#aad7ca}.lesson-card:before{content:"";width:70px;height:10px;background:var(--card);border-radius:999px}.feature-band{margin:100px 0 0;padding:50px;display:grid;grid-template-columns:1fr 1.1fr;gap:50px;background:var(--ink);color:var(--surface);border-radius:var(--radius)}.feature-band h2{font-size:clamp(2.4rem,5vw,4.8rem);line-height:1;margin:0}.feature-band ol{margin:0;padding:0;display:grid;grid-template-columns:1fr 1fr;gap:18px;list-style:none}.feature-band li{padding:20px;background:#25322d;border-radius:var(--radius-sm)}.feature-band b{display:block;color:#f39b83;font-size:1.6rem}.lesson-layout{display:grid;grid-template-columns:minmax(0,1fr) 290px;gap:70px;align-items:start}.lesson-hero{padding:30px 0 60px;border-bottom:1px solid var(--line)}.lesson-hero .lesson-index{display:inline-block;margin-bottom:24px;padding:6px 11px;background:var(--card,#cde59d);border-radius:999px;font-weight:850}.lesson-hero h1{max-width:900px;margin:0;font-size:clamp(3rem,7vw,6.5rem);line-height:.95;letter-spacing:-.06em}.lesson-hero .lead{max-width:650px;color:var(--muted);font-size:1.25rem}.outcome-grid{margin:40px 0;display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.outcome{padding:20px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--surface)}.lesson-section{padding:54px 0;border-bottom:1px solid var(--line)}.lesson-section h2{margin:0 0 14px;font-size:clamp(1.8rem,3vw,3rem);letter-spacing:-.035em}.lesson-section p{max-width:760px;color:var(--muted);font-size:1.08rem}.challenge-box{margin:54px 0;padding:36px;background:var(--ink);color:var(--surface);border-radius:var(--radius)}.challenge-box h2{font-size:2.2rem;margin:0 0 12px}.lesson-side{position:sticky;top:calc(var(--header) + 28px);padding:22px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}.lesson-side h2{font-size:1rem}.lesson-side label{display:flex;gap:10px;align-items:flex-start;margin:12px 0}.lesson-side .button{width:100%;margin-top:16px}.lesson-nav{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:50px}.lesson-nav a{padding:22px;border:1px solid var(--line);border-radius:var(--radius-sm);text-decoration:none}.lesson-nav a:last-child{text-align:right}.practice-layout{display:grid;grid-template-columns:270px 1fr;gap:28px}.practice-tabs{position:sticky;top:calc(var(--header) + 28px);align-self:start;display:grid;gap:8px}.practice-tabs button{padding:14px 16px;border:1px solid var(--line);border-radius:var(--radius-sm);background:transparent;text-align:left;cursor:pointer}.practice-tabs button.active{background:var(--ink);color:var(--surface)}.practice-panel{min-width:0;padding:32px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface)}.practice-panel h2{font-size:2rem}.question{margin:26px 0;padding-top:26px;border-top:1px solid var(--line)}.question:first-of-type{border-top:0}.option-list{display:grid;grid-template-columns:1fr 1fr;gap:10px}.option{padding:14px;border:1px solid var(--line);border-radius:var(--radius-sm);background:transparent;text-align:left;cursor:pointer}.option.selected{border-color:var(--ink);background:var(--surface-2)}.quiz-result{margin-top:28px;padding:22px;border-radius:var(--radius-sm);background:var(--surface-2)}.quiz-result.good{background:#d9ead5}.code-workspace{display:grid;grid-template-columns:1fr 1fr;gap:16px}.editor-group label{display:block;margin-bottom:8px;font-weight:750}.code-editor{width:100%;min-height:410px;padding:18px;resize:vertical;border:1px solid #46504b;border-radius:var(--radius-sm);background:#17211d;color:#f1f4ed;font-family:"SFMono-Regular",Consolas,monospace;font-size:.85rem;line-height:1.6;tab-size:2}.preview-frame{width:100%;min-height:448px;border:1px solid var(--line);border-radius:var(--radius-sm);background:white}.task-note{margin-bottom:20px;padding:18px;border-left:5px solid var(--accent);background:#f3ded7}.timer-shell{max-width:900px}.timer-display{margin:30px 0;font-variant-numeric:tabular-nums;font-size:clamp(4.5rem,14vw,10rem);line-height:.9;letter-spacing:-.07em}.timer-presets{display:flex;flex-wrap:wrap;gap:9px}.timer-presets button{padding:9px 14px;border:1px solid var(--line);border-radius:999px;background:transparent;cursor:pointer}.timer-presets button.active{background:var(--ink);color:var(--surface)}.milestones{margin-top:40px;display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.milestone{padding:18px;border:1px solid var(--line);border-radius:var(--radius-sm)}.milestone.passed{background:#d9ead5}.resource-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.resource{min-height:210px;padding:28px;display:flex;flex-direction:column;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface);text-decoration:none}.resource h2{margin:auto 0 6px;font-size:1.65rem}.resource p{margin:0;color:var(--muted)}.site-footer{padding:48px max(20px,calc((100vw - var(--max))/2));display:grid;grid-template-columns:1fr 1fr;gap:40px;background:var(--ink);color:var(--surface)}.site-footer p{max-width:600px;color:#bfc8c3}.noscript{padding:20px;background:#fff1c4}.empty-state{padding:70px 30px;text-align:center}.empty-state h1{font-size:3rem}.visually-hidden{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}
@media(max-width:1050px){.site-header{grid-template-columns:auto auto 1fr}.header-progress{display:none}.site-nav{justify-content:flex-end}.hero{grid-template-columns:1fr}.hero-copy{padding-top:30px}.work-preview{transform:none}.work-preview iframe{height:540px}.lesson-card,.lesson-card:nth-child(n){grid-column:span 6}.feature-band{grid-template-columns:1fr}.lesson-layout{grid-template-columns:1fr}.lesson-side{position:static}.practice-layout{grid-template-columns:1fr}.practice-tabs{position:static;grid-template-columns:repeat(3,1fr)}}
@media(max-width:760px){:root{--header:68px}.page-shell{width:min(100% - 28px,var(--max));padding-top:30px}.site-header{padding:0 14px;grid-template-columns:1fr auto}.site-nav{position:absolute;left:14px;right:14px;top:62px;padding:18px;display:none;flex-direction:column;align-items:stretch;background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow)}.site-nav.open{display:flex}.menu-button{display:block}.brand small{display:none}.hero{min-height:calc(100dvh - var(--header));padding:44px 0 70px}.hero h1{font-size:clamp(3.1rem,16vw,5rem)}.work-preview{display:none}.home-stats{grid-template-columns:1fr}.home-stat{min-height:120px;border-right:0;border-bottom:1px solid var(--line)}.home-stat:last-child{border-bottom:0}.lesson-card,.lesson-card:nth-child(n){grid-column:1/-1;min-height:270px}.feature-band{padding:28px}.feature-band ol{grid-template-columns:1fr}.outcome-grid{grid-template-columns:1fr}.lesson-nav{grid-template-columns:1fr}.lesson-nav a:last-child{text-align:left}.practice-tabs{display:flex;overflow:auto}.practice-tabs button{flex:0 0 auto}.practice-panel{padding:20px}.option-list,.code-workspace,.milestones,.resource-grid,.site-footer{grid-template-columns:1fr}.timer-display{font-size:25vw}}
@media(prefers-color-scheme:dark){:root{--bg:#111714;--surface:#18201c;--surface-2:#222d28;--ink:#edf1ec;--muted:#aab5af;--line:#3d4943;--accent:#f07a60;--accent-ink:#28100b;--focus:#88d6c5;--shadow:0 18px 50px rgb(0 0 0/.25)}.site-header{background:rgb(17 23 20/.94)}.code-editor{background:#0a0f0d}.task-note{background:#43271f}.quiz-result.good,.milestone.passed{background:#22452f}.brand-mark,.button,.practice-tabs button.active,.timer-presets button.active{background:#edf1ec;color:#17211d}.feature-band{background:#e9eee8;color:#17211d}.feature-band li{background:#d6ded9}.site-footer{background:#080c0a}.preview-toolbar{color:#1c2c25}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.button:active{transform:none}}

/* Typography and spacing refinement */
:root{--max:1480px}
body{line-height:1.75;letter-spacing:.015em}
.page-shell{width:min(var(--max),calc(100% - 56px));padding:64px 0 120px}
.hero{min-height:calc(100dvh - var(--header));padding:56px 0 72px;grid-template-columns:minmax(560px,.92fr) minmax(540px,1.08fr);gap:clamp(56px,6vw,112px)}
.kicker{margin-bottom:22px;letter-spacing:.14em}
.hero h1{max-width:780px;font-size:clamp(3.5rem,4.6vw,5.25rem);line-height:1.08;letter-spacing:-.04em;word-break:keep-all;text-wrap:balance}
.hero h1 span{margin-top:.08em}
.hero .summary{max-width:570px;margin:36px 0 40px;font-size:clamp(1.04rem,1.25vw,1.22rem);line-height:1.9;letter-spacing:.025em}
.work-preview{transform:rotate(.5deg)}
.preview-toolbar{height:38px;padding:0 10px;font-size:.72rem;letter-spacing:.03em}
.work-preview iframe{height:min(600px,64vh)}
.section-heading{max-width:860px;margin-bottom:56px}
.section-heading h1,.section-heading h2{margin-bottom:24px;font-size:clamp(2.5rem,4.6vw,4.8rem);line-height:1.12;letter-spacing:-.04em;text-wrap:balance}
.section-heading p{max-width:680px;font-size:1.1rem;line-height:1.9}
.lesson-card{min-height:350px;padding:32px}
.lesson-card h3{margin-bottom:18px;font-size:clamp(1.7rem,2.7vw,2.8rem);line-height:1.16;letter-spacing:-.025em}
.lesson-card p{line-height:1.85}

@media(max-width:1180px){.hero{grid-template-columns:1fr;gap:56px}.hero-copy{padding-top:24px}.work-preview{transform:none}.work-preview iframe{height:560px}}
@media(max-width:760px){.page-shell{width:min(100% - 32px,var(--max));padding:36px 0 88px}.hero{min-height:calc(100dvh - var(--header));padding:48px 0 64px}.hero h1{font-size:clamp(3rem,14vw,4.25rem);line-height:1.08}.hero .summary{margin:28px 0 32px;font-size:1rem;line-height:1.85}.lesson-card{min-height:290px;padding:26px}}

/* Full lesson reading experience */
.reading-layout{grid-template-columns:minmax(0,900px) 330px;justify-content:space-between;gap:clamp(48px,6vw,96px)}
.reading-layout .lesson-content{min-width:0}
.reading-layout .lesson-hero{padding-top:40px;padding-bottom:72px}
.reading-layout .lesson-hero h1{font-size:clamp(3.25rem,5.5vw,5.8rem);line-height:1.08;letter-spacing:-.045em;word-break:keep-all}
.reading-layout .lesson-hero .lead{max-width:680px;margin-top:28px;line-height:1.9}
.reading-layout .outcome-grid{margin-top:52px;gap:16px}
.reading-layout .outcome{padding:24px}
.reading-layout .outcome p{margin-bottom:0;line-height:1.75}
.rich-lesson{padding:80px 0;scroll-margin-top:calc(var(--header) + 24px)}
.chapter-heading{display:grid;grid-template-columns:56px 1fr;gap:22px;align-items:start;margin-bottom:44px}
.chapter-heading>span{padding-top:9px;color:var(--accent);font-size:.8rem;font-weight:850;letter-spacing:.08em}
.chapter-heading p{margin:0 0 7px;color:var(--muted);font-size:.78rem;font-weight:750;letter-spacing:.06em}
.chapter-heading h2{max-width:720px;margin:0;font-size:clamp(2rem,3.5vw,3.3rem);line-height:1.18;letter-spacing:-.03em;text-wrap:balance}
.prose{width:calc(100% - 78px);max-width:75ch;min-width:0;margin-left:78px;color:var(--muted);font-size:1.06rem;line-height:1.95}
.prose>*+*{margin-top:28px}
.prose h3{margin-top:48px;margin-bottom:16px;color:var(--ink);font-size:1.3rem;line-height:1.4;letter-spacing:-.01em}
.prose p{margin-bottom:0}
.prose ul,.prose ol{padding-left:1.4em}
.prose li+li{margin-top:10px}
.prose strong{color:var(--ink)}
.lesson-visual{width:100%;margin:0 0 36px}
.lesson-visual img{width:100%;height:auto;display:block;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface-2);box-shadow:0 14px 34px rgb(23 33 29/.09)}
.lesson-visual figcaption{margin-top:12px;padding-left:14px;border-left:3px solid var(--accent);color:var(--muted);font-size:.9rem;line-height:1.7}
.concept-animation{width:100%;margin:0 0 44px;border:1px solid var(--line);border-radius:var(--radius);overflow:hidden;background:var(--surface);box-shadow:0 14px 34px rgb(23 33 29/.08)}
.animation-canvas{width:100%;background:#f4efe3}
.animation-canvas svg{width:100%;height:auto;display:block}
.concept-animation figcaption{padding:18px 22px 0;display:grid;gap:5px;color:var(--muted);font-size:.92rem;line-height:1.65}
.concept-animation figcaption strong{color:var(--ink);font-size:1.05rem}
.animation-controls{padding:18px 22px 22px;display:flex;flex-wrap:wrap;align-items:center;gap:9px}
.animation-controls button{min-width:76px;min-height:44px;padding:9px 15px;border:1px solid var(--ink);border-radius:999px;background:transparent;color:var(--ink);font-weight:750;cursor:pointer}
.animation-controls button:first-child{background:var(--ink);color:var(--surface)}
.animation-controls button:disabled{opacity:.45;cursor:not-allowed}
.animation-status{margin-left:auto;color:var(--muted);font-size:.82rem;font-weight:700}
.anim-bg{fill:#f4efe3}.anim-stage{fill:#17211d}.anim-card{fill:#fffaf0;stroke:#cbd3ce;stroke-width:2}.anim-result{fill:#aad7ca}.anim-block{fill:#f07a60}.anim-block.alt{fill:#aad7ca}.anim-block.warm{fill:#ead589}.anim-text{fill:#17211d;font-family:"Avenir Next",Arial,sans-serif;font-size:20px;font-weight:750}.anim-label{font-size:18px}.anim-number{fill:#e45f45;font-size:16px}.anim-code{font-family:"SFMono-Regular",Consolas,monospace;font-size:18px}.anim-winner{fill:#17211d;font-size:27px}.anim-line,.anim-axis{fill:none;stroke:#e45f45;stroke-width:9;stroke-linecap:round}.cross-row,.cross-col{stroke:#ead589}.axis-label{fill:#edf1ec;font-size:16px}.vertical-label{writing-mode:vertical-rl}.flex-column-axes{opacity:0}.anim-grid-line{fill:none;stroke:#59645f;stroke-width:3}.anim-track{fill:none;stroke:#59645f;stroke-width:10;stroke-linecap:round}.box-margin{fill:#ead589}.box-border{fill:#f07a60}.box-padding{fill:#aad7ca}.box-content{fill:#cbbfe4}.box-label{font-size:16px}.box-guide{fill:none;stroke:#17211d;stroke-width:3;stroke-linecap:round}.origin-point{fill:#17211d}.origin-card{transform-box:view-box}.bubble-dot{fill:#e45f45;opacity:.15}
.anim-step{opacity:.22;transform:translateY(8px);transform-box:fill-box;transform-origin:center}
.show-static-steps .anim-step,.show-static-steps .bubble-dot{opacity:1;transform:none}
.concept-animation.is-playing .anim-step{animation:concept-step 650ms ease forwards}
.concept-animation.is-playing .anim-step-1{animation-delay:0ms}.concept-animation.is-playing .anim-step-2{animation-delay:750ms}.concept-animation.is-playing .anim-step-3{animation-delay:1500ms}.concept-animation.is-playing .anim-step-4{animation-delay:2250ms}.concept-animation.is-playing .anim-step-5{animation-delay:3000ms}
.concept-animation.is-playing .flex-items .one{animation:flex-one-demo 4.8s ease-in-out both}.concept-animation.is-playing .flex-items .two{animation:flex-two-demo 4.8s ease-in-out both}.concept-animation.is-playing .flex-items .three{animation:flex-three-demo 4.8s ease-in-out both}.concept-animation.is-playing .flex-row-axes{animation:flex-row-axes-demo 4.8s ease-in-out both}.concept-animation.is-playing .flex-column-axes{animation:flex-column-axes-demo 4.8s ease-in-out both}
.concept-animation.is-playing .transition-dot{animation:transition-demo 3.6s ease-in-out both}.transition-dot{fill:#e45f45}
.concept-animation.is-playing .origin-center{animation:rotate-center-demo 3.6s ease-in-out both;transform-origin:280px 235px}.concept-animation.is-playing .origin-corner{animation:rotate-corner-demo 3.6s ease-in-out both;transform-origin:565px 310px}
.concept-animation.is-playing .keyframe-dot{animation:keyframe-demo 4.2s ease-in-out both}.keyframe-dot{fill:#e45f45}
.concept-animation.is-playing .event-pulse{animation:event-flow-demo 5s steps(4,end) both}.event-pulse{fill:#e45f45}
.concept-animation.is-playing .toggle-menu{animation:menu-open-demo 3.4s ease both;transform-box:fill-box;transform-origin:top center}
.concept-animation.is-playing .bubble-1{animation:bubble-demo 750ms ease 400ms forwards}.concept-animation.is-playing .bubble-2{animation:bubble-demo 750ms ease 1200ms forwards}.concept-animation.is-playing .bubble-3{animation:bubble-demo 750ms ease 2000ms forwards}.concept-animation.is-playing .bubble-4{animation:bubble-demo 750ms ease 2800ms forwards}
.learning-guide{margin:32px 0 16px;padding:18px 20px;border-left:5px solid var(--accent);border-radius:0 var(--radius-sm) var(--radius-sm) 0;background:var(--surface-2);color:var(--ink)}.learning-guide p{margin:5px 0 0!important;font-size:.94rem!important}
.student-live-demo{margin:24px 0;padding:22px;border:1px solid var(--line);border-radius:var(--radius-sm);background:#f4f7f3;color:var(--ink)}
.student-live-demo .demo-eyebrow{margin:0 0 10px;color:var(--muted);font-size:.78rem;font-weight:850;letter-spacing:.08em;text-transform:uppercase}
.student-live-demo .demo-message{margin:0 0 14px;padding:15px 16px;border-radius:10px;background:#e4e8e5;transition:background-color .2s ease,color .2s ease}
.student-live-demo .demo-message.is-success{background:#d8eee6;color:#145847;font-weight:800}
.student-live-demo button{min-height:44px;margin:0 8px 8px 0;padding:10px 16px;border:1px solid var(--ink);border-radius:999px;background:var(--ink);color:#fff;font:inherit;font-weight:750;cursor:pointer}
.student-live-demo .demo-reset{background:transparent;color:var(--ink)}
.student-live-demo label{display:block;margin-bottom:8px;font-weight:800}
.student-live-demo input{width:100%;min-height:46px;padding:10px 12px;border:1px solid #87958e;border-radius:8px;background:#fff;color:var(--ink);font:inherit}
.student-live-demo input:focus-visible{outline:3px solid #74b8a7;outline-offset:2px}
.student-live-demo .demo-count{margin:5px 0 0;color:var(--muted);font-size:.85rem;text-align:right}
.concept-animation.is-paused *{animation-play-state:paused!important}
@keyframes concept-step{to{opacity:1;transform:none}}
@keyframes flex-one-demo{0%,42%{transform:none}58%,100%{transform:translate(180px,-85px)}}
@keyframes flex-two-demo{0%,42%{transform:none}58%,100%{transform:translate(0,5px)}}
@keyframes flex-three-demo{0%,42%{transform:none}58%,100%{transform:translate(-180px,95px)}}
@keyframes flex-row-axes-demo{0%,42%{opacity:1}58%,100%{opacity:0}}
@keyframes flex-column-axes-demo{0%,42%{opacity:0}58%,100%{opacity:1}}
@keyframes transition-demo{0%{transform:translateX(0) scale(1)}50%{transform:translateX(330px) scale(1.35)}100%{transform:translateX(645px) scale(1)}}
@keyframes rotate-center-demo{0%,15%{transform:rotate(0)}70%,100%{transform:rotate(35deg)}}
@keyframes rotate-corner-demo{0%,15%{transform:rotate(0)}70%,100%{transform:rotate(35deg)}}
@keyframes keyframe-demo{0%{transform:translateX(0) translateY(0) scale(1)}50%{transform:translateX(335px) translateY(-90px) scale(1.6)}100%{transform:translateX(670px) translateY(0) scale(1)}}
@keyframes event-flow-demo{0%{transform:translateX(0)}100%{transform:translateX(760px)}}
@keyframes menu-open-demo{0%,35%{opacity:.18;transform:scaleY(.12)}75%,100%{opacity:1;transform:scaleY(1)}}
@keyframes bubble-demo{0%{opacity:.15;transform:scale(.6)}60%{opacity:1;transform:scale(1.7)}100%{opacity:.55;transform:scale(1)}}
@media(max-width:760px){.concept-animation{margin-bottom:34px}.concept-animation figcaption,.animation-controls{padding-left:16px;padding-right:16px}.animation-status{width:100%;margin:4px 0 0}.animation-controls button{flex:1 1 90px}}
@media(prefers-reduced-motion:reduce){.concept-animation *{animation:none!important}.concept-animation .anim-step,.concept-animation .bubble-dot{opacity:1;transform:none}.animation-controls button[data-animation-action="pause"]{display:none}}
.download-callout{max-width:820px;padding:24px;display:flex;align-items:center;justify-content:space-between;gap:24px;border:1px solid var(--line);border-radius:var(--radius);background:var(--surface-2);color:var(--ink)}
.download-callout p{margin:6px 0 0;font-size:.98rem}
.download-callout .button{flex:0 0 auto}
.download-callout strong{display:block;margin-top:8px;font-size:1.35rem}
.download-label{display:inline-flex;padding:4px 9px;border-radius:999px;background:var(--accent);color:var(--accent-ink);font-size:.75rem;font-weight:850;letter-spacing:.04em}
.download-primary{min-height:52px;padding-inline:22px;text-align:center}
.download-help{max-width:820px!important;margin-top:12px!important;font-size:.94rem!important}
.integrated-reference{scroll-margin-top:calc(var(--header) + 22px)}
.integrated-reference .prose>h3:first-child{margin-top:0}
.integrated-reference details{padding:18px 20px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--surface)}
.integrated-reference summary{color:var(--ink);font-weight:800;cursor:pointer}
.lesson-side{max-height:calc(100dvh - var(--header) - 56px);overflow:auto}
.prose pre{max-width:100%;padding:24px;overflow:auto;border:1px solid var(--line);border-radius:var(--radius-sm);background:#111714;color:#edf1ec;line-height:1.65;tab-size:2}
.prose code{font-family:"SFMono-Regular",Consolas,monospace;font-size:.88rem}
.table-wrap{display:block;width:100%;max-width:100%;min-width:0;overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius-sm)}
.prose table{width:100%;min-width:640px;border-collapse:collapse;background:var(--surface);color:var(--ink);font-size:.94rem;line-height:1.65}
.prose th,.prose td{padding:17px 18px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
.prose th{background:var(--surface-2);font-size:.82rem;letter-spacing:.04em}
.prose tr:last-child td{border-bottom:0}
.lesson-note,.exercise{padding:24px 26px;border-radius:var(--radius-sm);background:var(--surface-2);color:var(--ink)}
.lesson-note{border-left:5px solid var(--focus)}
.teacher-note{border-left-color:var(--accent)}
.exercise{border:1px solid var(--line);background:var(--surface)}
.lesson-note p,.exercise p{margin:8px 0 0;color:var(--muted)}
.inline-demo{min-height:48px;padding:14px 18px;display:inline-flex;align-items:center;border:1px solid var(--line);border-radius:999px;color:var(--ink);font-weight:750;text-decoration:none}
.lesson-side{padding:26px;max-height:calc(100dvh - var(--header) - 56px);overflow:auto}
.lesson-toc h2,.lesson-checks h2{margin:0 0 18px;font-size:.92rem;letter-spacing:.04em}
.lesson-toc ol{margin:0;padding:0;list-style:none}
.lesson-toc li+li{margin-top:5px}
.lesson-toc a{min-height:46px;padding:9px 0;display:grid;grid-template-columns:30px 1fr;align-items:center;gap:8px;color:var(--muted);font-size:.9rem;line-height:1.45;text-decoration:none}
.lesson-toc a:hover,.lesson-toc a:focus-visible{color:var(--ink)}
.lesson-toc a span{color:var(--accent);font-size:.72rem;font-weight:850}
.lesson-checks{margin-top:28px;padding-top:26px;border-top:1px solid var(--line)}
.lesson-checks label{line-height:1.55}

@media(max-width:1180px){.reading-layout{grid-template-columns:1fr}.lesson-side{position:static;max-height:none;display:grid;grid-template-columns:1fr 1fr;gap:32px}.lesson-checks{margin:0;padding:0 0 0 32px;border-top:0;border-left:1px solid var(--line)}}
@media(max-width:760px){.page-shell,.reading-layout{width:min(var(--max),calc(100% - 32px))}.reading-layout .lesson-hero{padding-top:20px;padding-bottom:52px}.reading-layout .lesson-hero h1{font-size:clamp(2.8rem,13vw,4.2rem)}.reading-layout .outcome-grid{margin-top:36px}.rich-lesson{padding:56px 0}.chapter-heading{grid-template-columns:36px minmax(0,1fr);gap:10px;margin-bottom:30px}.chapter-heading h2{font-size:clamp(1.8rem,8vw,2.5rem)}.prose{width:100%;margin-left:0;font-size:1rem;line-height:1.9}.prose pre{padding:18px}.download-callout{align-items:stretch;flex-direction:column}.download-callout .button{width:100%}.lesson-side{grid-template-columns:minmax(0,1fr);padding:22px}.lesson-checks{padding:24px 0 0;border-left:0;border-top:1px solid var(--line)}}
@media(max-width:760px){.reading-layout .lesson-hero h1{word-break:normal;overflow-wrap:anywhere}}

/* Fixed-template adaptation lab */
.template-lab{display:grid;grid-template-columns:minmax(280px,.8fr) minmax(0,1.2fr);gap:28px;align-items:start;margin-top:32px}
.template-controls{display:grid;gap:18px}
.field{display:grid;gap:7px}
.field label{font-weight:750}
.field input,.field textarea,.field select{width:100%;min-height:48px;padding:11px 13px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--bg);color:var(--ink)}
.field textarea{resize:vertical}
.field input[type=color]{height:52px;padding:6px}
.template-preview{min-height:660px}
.ready-checks{display:grid;gap:12px;margin:24px 0}
.ready-checks .option span{display:flex;align-items:flex-start;gap:12px}
.ready-checks .option b{display:grid;flex:0 0 28px;width:28px;height:28px;place-items:center;border-radius:50%;background:var(--ink);color:var(--surface);font-size:.8rem}
.practice-hint{margin-top:18px;padding:16px 18px;border:1px solid var(--line);border-radius:var(--radius-sm);background:var(--surface)}
.practice-hint summary{min-height:44px;display:flex;align-items:center;font-weight:800;cursor:pointer}
.practice-hint code{font-family:"SFMono-Regular",Consolas,monospace}
@media(max-width:900px){.template-lab{grid-template-columns:1fr}.template-preview{min-height:720px}}

/* Downloadable resource cards */
.robot-callout{margin:0 0 28px;padding:30px;display:flex;align-items:center;justify-content:space-between;gap:30px;border:1px solid var(--line);border-radius:var(--radius);background:var(--ink);color:var(--surface)}
.robot-callout h2{margin:0 0 8px;font-size:clamp(1.7rem,3vw,2.6rem);line-height:1.15}.robot-callout p{max-width:680px;margin:0;color:#c8d1cc}.robot-callout .kicker{margin-bottom:8px;color:#f39b83}.robot-callout .button{flex:0 0 auto}
@media(max-width:760px){.robot-callout{align-items:stretch;flex-direction:column;padding:24px}.robot-callout .button{width:100%}}
.resource{min-height:240px;text-decoration:none}
.resource-tag{align-self:flex-start;padding:5px 9px;border-radius:999px;background:var(--surface-2);color:var(--muted);font-size:.74rem;font-weight:800;letter-spacing:.04em}
.resource-actions{margin-top:24px;display:flex;flex-wrap:wrap;gap:10px}
.resource-actions a{min-height:44px;padding:10px 15px;display:inline-flex;align-items:center;justify-content:center;border:1px solid var(--ink);border-radius:999px;text-decoration:none;font-weight:750}
.resource-preview{background:transparent;color:var(--ink)}
.resource-download{background:var(--ink);color:var(--surface)}
.resource-actions a:hover{border-color:var(--accent)}
.resource-actions a:active{transform:translateY(1px)}