:root{--red:#9C4310;--red-dark:#6E2E0B;--ink:#202622;--muted:#5f6761;--line:#d9ded9;--paper:#fff;--wash:#f3f5f1;--tint:#fff0f0;--serif:'Libre Caslon Display',Georgia,serif;--sans:'DM Sans',Arial,sans-serif}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 var(--sans)}button,input,select,textarea{font:inherit}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}a{color:inherit;text-underline-offset:4px}button{cursor:pointer}button:disabled{cursor:default;opacity:.5}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:3px solid #005b94;outline-offset:4px}h1,h2,h3,p{margin:0}h1,h2{font-family:var(--serif);font-weight:400;line-height:1.05}h1{font-size:clamp(2.8rem,5.1vw,5rem);letter-spacing:-.03em}h2{font-size:2.7rem}h3{font-size:1.15rem;line-height:1.4}p+p{margin-top:1rem}svg{display:block}button{border:1px solid var(--line);background:white;color:var(--ink);border-radius:4px;padding:.65rem 1rem;transition:background .15s}button:hover{background:var(--wash)}.skip-link{position:absolute;top:-80px;left:20px;background:white;padding:16px;z-index:99}.skip-link:focus{top:10px}.site-header{display:flex;align-items:center;justify-content:space-between;gap:2rem;padding:24px 4.5%;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;font-size:22px;line-height:1.04;letter-spacing:-.7px;font-weight:700}.brand-second{display:block;font-weight:400}.brand-symbol{font-family:Arial,sans-serif;font-weight:700;font-size:54px;line-height:46px;color:var(--red);height:52px;position:relative;padding:0 4px 5px}.brand-symbol span{position:absolute;bottom:0;left:0;right:0;height:5px;background:var(--red)}.site-header nav{display:flex;gap:2rem;font-size:15px}.site-header nav a{text-decoration:none;padding:8px 0;border-bottom:2px solid transparent}.site-header nav a.active{border-color:var(--red)}.edition{font-size:12px;letter-spacing:.08em;display:flex;align-items:center;gap:14px}.edition span{background:var(--ink);color:white;padding:5px 8px;font-size:14px}.page{max-width:1440px;margin:auto;padding:42px 4.5% 72px}.eyebrow{font-size:12px;letter-spacing:.13em;font-weight:700;text-transform:uppercase;display:flex;gap:12px;align-items:center;margin-bottom:24px}.eyebrow .station-dot{width:12px;height:12px;border:3px solid var(--red);border-radius:50%}.hero{display:grid;grid-template-columns:1.05fr 1fr;gap:6%;align-items:start}.hero-title{max-width:620px}.hero h1 em{color:var(--red);font-style:normal}.lede{color:var(--muted);font-size:18px;max-width:490px;margin:24px 0}.tags{display:flex;gap:8px;flex-wrap:wrap}.tag{font-size:13px;padding:3px 9px;background:var(--wash);border:1px solid var(--line);border-radius:2px}.hero-bottom{display:flex;align-items:center;gap:18px;margin-top:30px;color:var(--muted);font-size:14px}.primary{background:var(--red);border-color:var(--red);color:white;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:24px;font-weight:600;border-radius:3px;padding:.85rem 1.25rem}.primary:hover{background:var(--red-dark)}.lab-preview{background:var(--wash);border:1px solid var(--line);padding:20px 22px 14px;position:relative}.panel-label{display:flex;justify-content:space-between;align-items:center;font-size:12px;letter-spacing:.06em;font-weight:700;text-transform:uppercase}.panel-label .quiet{font-weight:400;color:var(--muted)}.plot{width:100%;height:auto;max-height:330px;overflow:visible}.preset-row{display:flex;gap:6px;flex-wrap:wrap;margin-top:4px}.preset-row button{padding:6px 12px;font-size:14px;border-color:#cbd2cb;background:transparent}.preset-row button.active{color:white;background:var(--ink);border-color:var(--ink)}.plot-caption{font-size:14px;color:var(--muted);margin-top:12px}.matrix{display:inline-grid;grid-template-columns:repeat(2,minmax(2ch,auto));gap:2px 13px;position:relative;padding:1px 9px;vertical-align:middle;line-height:1.5;text-align:center;font-family:Georgia,serif;font-size:1.05em}.matrix:before,.matrix:after{content:'';position:absolute;top:0;bottom:0;width:4px;border:1.5px solid currentColor}.matrix:before{left:0;border-right:0}.matrix:after{right:0;border-left:0}.resource-section{margin-top:52px}.section-head{display:flex;align-items:baseline;justify-content:space-between;gap:20px;padding-bottom:18px;border-bottom:1px solid var(--ink)}.section-head h2{font-size:2rem}.section-head p{color:var(--muted);font-size:14px}.resource-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:26px;margin-top:24px}.resource-card{display:flex;flex-direction:column;text-decoration:none;border:1px solid var(--line);padding:23px;min-height:245px;position:relative;transition:border-color .15s,transform .15s}.resource-card:hover{border-color:var(--red);transform:translateY(-3px)}.resource-type{font-size:12px;letter-spacing:.12em;text-transform:uppercase;color:var(--red);font-weight:700}.resource-card h3{font-family:var(--serif);font-size:2rem;font-weight:400;line-height:1.08;margin:17px 0 10px;letter-spacing:-.02em}.resource-card p{color:var(--muted);font-size:15px}.card-foot{display:flex;justify-content:space-between;align-items:center;font-size:13px;margin-top:auto;padding-top:24px}.card-arrow{font-size:22px;color:var(--red)}.connection-bar{margin-top:30px;border-top:1px solid var(--line);display:flex;align-items:center;gap:26px;padding-top:20px;font-size:14px;color:var(--muted)}.connection-bar strong{font-size:12px;letter-spacing:.08em;color:var(--ink)}footer{border-top:1px solid var(--line);padding:24px 4.5%;display:flex;justify-content:space-between;gap:24px;font-size:12px;color:var(--muted)}.footer-sep{margin:0 10px;color:var(--red)}.back-link{display:inline-block;font-size:14px;color:var(--muted);margin-bottom:24px;text-decoration:none}.subhead{max-width:820px;margin-bottom:32px}.subhead h1{font-size:clamp(2.7rem,4vw,4.2rem)}.subhead .lede{max-width:720px}.content-narrow{max-width:820px}.prose{line-height:1.75}.prose h2{font-size:2.3rem;margin:36px 0 18px}.prose h3{margin:26px 0 12px}.prose a{color:var(--red)}.note{padding:20px 24px;border-left:3px solid var(--red);background:var(--wash);margin:24px 0}.muted{color:var(--muted)}[hidden]{display:none!important}
@media(max-width:900px){.edition{display:none}.hero{gap:4%}.hero h1{font-size:3.7rem}.resource-grid{gap:16px}.resource-card{padding:19px}.site-header nav{gap:1.1rem}}
@media(max-width:680px){.site-header{padding:18px 5%;flex-wrap:wrap;gap:16px}.brand{font-size:20px}.site-header nav{order:2;width:100%;justify-content:space-between;font-size:14px;gap:10px}.page{padding:26px 5% 48px}.hero{grid-template-columns:1fr;gap:30px}.hero h1{font-size:3.6rem}.eyebrow{margin-bottom:18px}.lede{font-size:17px}.hero-bottom{margin-top:23px;gap:15px}.resource-section{margin-top:34px}.resource-grid{grid-template-columns:1fr;gap:14px}.resource-card{min-height:200px}.section-head{align-items:start;flex-direction:column;gap:8px}.connection-bar{flex-wrap:wrap;gap:12px}footer{flex-direction:column;gap:10px;padding:24px 5%}.lab-preview{padding:18px}.tag{font-size:13px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
.brand-symbol{font-size:0;background:var(--red);width:48px;height:48px;mask:url('logo.png') center/contain no-repeat;-webkit-mask:url('logo.png') center/contain no-repeat;padding:0}.brand-symbol span{display:none}.brand-mark-large{width:110px;height:110px;background:var(--red);mask:url('logo.png') center/contain no-repeat;-webkit-mask:url('logo.png') center/contain no-repeat}.activity-head{display:flex;align-items:flex-end;justify-content:space-between;gap:20px;margin-bottom:28px}.activity-head h1{font-size:clamp(2.4rem,4.3vw,4rem)}.activity-head .eyebrow{margin-bottom:12px}.activity-head .lede{font-size:16px;max-width:750px;margin:16px 0 0}.toolbar{display:flex;gap:8px;flex-wrap:wrap}.toolbar a,.secondary{font-size:14px;text-decoration:none;border:1px solid var(--line);border-radius:3px;padding:8px 13px;background:white;display:inline-flex;align-items:center;justify-content:center}.toolbar a:hover,.secondary:hover{border-color:var(--ink);background:var(--wash)}.set-picker{display:flex;gap:4px;padding:4px;background:var(--wash);border:1px solid var(--line);width:fit-content;max-width:100%;margin:0 0 24px}.set-picker button{border:0;background:transparent;padding:9px 17px;font-size:15px}.set-picker button.active{background:var(--ink);color:white}.activity-layout{display:grid;grid-template-columns:minmax(210px,260px) minmax(0,1fr);gap:36px;align-items:start}.activity-sidebar{border-top:3px solid var(--red);padding-top:18px}.activity-sidebar h2{font-family:var(--sans);font-size:16px;font-weight:700;line-height:1.4}.activity-sidebar p{font-size:14px;color:var(--muted);margin-top:9px}.case-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:6px;margin:18px 0}.case-grid button{padding:7px 0;font-size:14px;border:1px solid var(--line);position:relative;border-radius:2px}.case-grid button.current{outline:2px solid var(--red);outline-offset:1px}.case-grid button.correct{background:#e4eee8;border-color:#a0b6a7}.case-grid button.incorrect{background:#fde7e7;border-color:#dbaaab}.case-grid button.checked:after{content:'';width:4px;height:4px;border-radius:50%;background:var(--ink);position:absolute;bottom:2px;left:calc(50% - 2px)}.legend{display:flex;gap:12px;flex-wrap:wrap;font-size:12px;color:var(--muted)}.legend span{display:flex;align-items:center;gap:5px}.legend i{width:9px;height:9px;display:block;border:1px solid var(--line)}.legend .ok{background:#e4eee8;border-color:#a0b6a7}.legend .review{background:#fde7e7;border-color:#dbaaab}.progress-track{height:4px;background:var(--line);margin:17px 0 9px}.progress-track span{display:block;background:var(--red);height:100%}.sidebar-link{display:block;margin-top:22px;font-size:14px}.question-card{border:1px solid var(--line);padding:30px 34px;min-height:380px;box-shadow:0 4px 24px #20262205}.case-top{font-size:12px;letter-spacing:.09em;font-weight:700;display:flex;align-items:center;justify-content:space-between;margin-bottom:24px}.case-type{color:var(--muted);letter-spacing:0;font-weight:400;font-size:13px}.question-prompt{font-family:Georgia,serif;font-size:clamp(1.4rem,2.3vw,1.85rem);line-height:1.6;margin:14px 0 25px;overflow-wrap:anywhere}.question-prompt .matrix{font-size:.85em;margin:0 5px}.choice-row{display:flex;gap:12px;margin:24px 0}.choice-row button{min-width:155px;font-size:16px;padding:12px 24px}.choice-row button.selected{border:2px solid var(--red);padding:11px 23px;background:var(--tint);color:var(--red);font-weight:700}.reason-label{display:block;font-size:14px;font-weight:600;margin:18px 0 8px}textarea{width:100%;resize:vertical;min-height:90px;border:1px solid #bac2ba;border-radius:3px;padding:12px 14px;line-height:1.55;background:white;color:var(--ink)}textarea::placeholder{color:#727a73}details{border-top:1px solid var(--line);padding:15px 0;font-size:15px}details summary{cursor:pointer;font-weight:600;list-style-position:outside;margin-left:17px;padding:2px 0}details[open] summary{margin-bottom:13px}details p,details ol,details ul{font-size:15px;line-height:1.7}details div.prose{padding:0 0 4px}details .note{margin:14px 0}.definition{background:var(--wash);border:1px solid var(--line);padding:13px 18px;margin-bottom:24px;max-width:100%}.definition summary{font-weight:500}.definition[open]{padding-bottom:18px}.math-line{font-family:Georgia,serif;font-size:1.2rem;margin:12px 0;overflow-wrap:anywhere}.question-actions{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-top:22px}.question-actions .primary{padding:.7rem 1.2rem}.feedback{border-left:3px solid #326748;background:#eff5f0;margin-top:24px;padding:20px 22px}.feedback.review-feedback{background:#fff2f1;border-color:var(--red)}.feedback h3{font-size:16px;margin:0 0 8px}.feedback p{font-size:15px;line-height:1.65}.feedback .misconception{font-size:13px;border-top:1px solid #d2dcd3;padding-top:10px;margin-top:13px;color:var(--muted)}.case-nav{display:flex;justify-content:space-between;gap:20px;margin-top:18px}.case-nav button{font-size:14px}.case-nav .next{border-color:var(--ink)}.discussion-note{font-size:14px;color:var(--muted);margin:20px 0 0}.side-small{font-size:12px!important;margin-top:22px!important}.generation-nav{display:flex;flex-direction:column;margin-top:16px;gap:3px}.generation-nav button{text-align:left;display:flex;gap:12px;font-size:14px;border-color:transparent;padding:9px 10px;background:transparent}.generation-nav button span{color:var(--muted);min-width:18px}.generation-nav button.active{background:var(--tint);color:var(--red);border-color:#f4d2d3}.generation-question{font-size:20px;line-height:1.65;font-family:Georgia,serif;margin:18px 0 24px}.generation-question p+p{margin-top:12px}.generation-title{font-family:var(--serif);font-size:2.5rem;margin-bottom:12px}.check-label{display:flex;align-items:start;gap:10px;font-size:14px;margin:16px 0 24px}.check-label input{margin-top:5px;accent-color:var(--red);width:17px;height:17px;flex-shrink:0}.example-list{padding-left:22px;margin:0}.example-list li{padding-left:5px;margin:12px 0}.investigation-layout{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,1fr);gap:40px;align-items:start}.investigation-copy h2{font-size:2.3rem;margin:30px 0 17px}.investigation-copy h2:first-child{margin-top:0}.investigation-copy p{margin:12px 0}.investigation-copy ol{padding-left:23px}.investigation-copy li{margin:14px 0;padding-left:5px}.lab-workspace{background:var(--wash);border:1px solid var(--line);padding:24px;position:sticky;top:24px}.lab-workspace .plot{max-height:none}.matrix-controls{display:flex;align-items:center;gap:20px;margin-top:18px}.matrix-inputs{display:grid;grid-template-columns:repeat(2,65px);gap:8px;border-left:2px solid var(--ink);border-right:2px solid var(--ink);padding:5px 10px}.matrix-inputs input{width:100%;text-align:center;padding:7px 2px;border:1px solid #aab5aa;border-radius:2px;background:white}.lab-readout{margin-top:20px;border-top:1px solid var(--line);padding-top:16px;font-size:14px}.lab-readout p+p{margin-top:6px}.hint-row{font-size:14px;color:var(--muted);margin-top:15px}.lesson-grid{display:grid;grid-template-columns:2fr 1fr;gap:50px;align-items:start}.lesson-plan{counter-reset:lesson;padding-left:0;list-style:none}.lesson-plan li{position:relative;border-top:1px solid var(--line);padding:20px 0 20px 48px}.lesson-plan li:before{counter-increment:lesson;content:counter(lesson);position:absolute;left:0;top:22px;font-size:14px;color:var(--red);font-weight:700}.lesson-plan li strong{display:block;margin-bottom:6px}.lesson-aside{background:var(--wash);padding:25px;border:1px solid var(--line)}.lesson-aside h3{margin-top:0}.lesson-aside li{margin:12px 0}.inline-links{display:flex;flex-wrap:wrap;gap:12px;margin:24px 0}.inline-links a{font-size:14px}.audit-strip{display:grid;grid-template-columns:repeat(3,1fr);border:1px solid var(--line);margin:28px 0}.audit-strip div{padding:20px;border-right:1px solid var(--line)}.audit-strip div:last-child{border:0}.audit-strip strong{font-family:var(--serif);font-size:2.7rem;font-weight:400;display:block}.audit-strip span{font-size:13px;color:var(--muted)}.about-intro{display:flex;align-items:center;justify-content:space-between;gap:30px}.about-intro .subhead{margin-bottom:0}.about-intro .subhead h1{max-width:700px}.roadmap{margin:25px 0;border:1px solid var(--line)}.roadmap-row{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:18px 22px;border-bottom:1px solid var(--line);font-size:15px}.roadmap-row:last-child{border-bottom:0}.roadmap-row.current{background:var(--tint);border-left:3px solid var(--red)}.roadmap-row small{font-size:13px;color:var(--muted);text-align:right}.source-list{list-style:none;padding:0}.source-list li{border-top:1px solid var(--line);padding:18px 0}.source-list li a{font-weight:600}.source-list li p{font-size:15px;margin-top:7px;color:var(--muted)}.colour-swatches{display:flex;gap:18px;margin:20px 0}.swatch{display:flex;align-items:center;gap:10px;font-size:14px}.swatch i{width:42px;height:42px;display:block;border-radius:2px}.print-sheet{max-width:940px}.print-sheet h1{font-size:2.8rem}.print-sheet h2{font-size:2rem;margin:36px 0 18px}.print-item{border:1px solid var(--line);padding:20px;margin:14px 0;break-inside:avoid}.print-item h3{font-size:15px;margin-bottom:12px}.print-item .print-question{font-family:Georgia,serif;font-size:18px;line-height:1.65}.answer-line{height:60px;margin-top:15px;border-bottom:1px solid var(--line)}.print-answer{margin-top:15px;font-size:15px;line-height:1.7}.error-message{color:var(--red);font-size:14px}.screen-reader{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@media(max-width:950px){.activity-layout{grid-template-columns:205px minmax(0,1fr);gap:24px}.question-card{padding:24px}.activity-head{align-items:start;flex-direction:column}.investigation-layout{gap:25px}.lesson-grid{gap:28px}.choice-row button{min-width:130px;padding-left:18px;padding-right:18px}}
@media(max-width:680px){.activity-layout{grid-template-columns:1fr;gap:22px}.activity-sidebar{padding-top:13px}.case-grid{grid-template-columns:repeat(12,1fr);gap:4px;margin:12px 0}.case-grid button{padding:6px 0;font-size:12px}.activity-sidebar .legend,.activity-sidebar .side-small,.activity-sidebar .sidebar-link{display:none}.activity-sidebar p{font-size:13px}.question-card{padding:22px 19px}.question-prompt{font-size:1.5rem}.choice-row{gap:10px}.choice-row button{min-width:0;flex:1;padding:12px 14px}.choice-row button.selected{padding:11px 13px}.set-picker{width:100%}.set-picker button{padding:9px;font-size:14px;flex:1}.generation-nav{display:grid;grid-template-columns:repeat(5,1fr);gap:5px}.generation-nav button{padding:7px;display:block;text-align:center;border:1px solid var(--line)}.generation-nav button .gen-label{display:none}.generation-nav button span{color:inherit}.investigation-layout{grid-template-columns:1fr}.lab-workspace{position:static;grid-row:1;padding:17px}.lesson-grid{grid-template-columns:1fr}.audit-strip div{padding:13px}.audit-strip strong{font-size:2rem}.about-intro{align-items:start}.about-intro .brand-mark-large{display:none}.roadmap-row{align-items:start;padding:15px;gap:12px}.roadmap-row small{max-width:130px}.colour-swatches{flex-direction:column}.question-actions{align-items:stretch}.question-actions button{font-size:14px}.case-top{gap:12px}.case-type{text-align:right}}
@media print{@page{margin:16mm;size:A4}.site-header,footer,.back-link,.toolbar,.no-print,.skip-link{display:none!important}body{font-family:Arial,sans-serif;font-size:11pt;color:#111;background:#fff}.page{padding:0;max-width:none}.print-sheet h1{font-size:29pt}.print-sheet h2{font-size:21pt;break-after:avoid}.print-sheet h3{break-after:avoid}.print-item{border-color:#aaa;padding:13px;margin:10px 0}.print-question{font-size:12pt!important}.print-answer{font-size:10pt}.answer-line{height:50px}.prose{font-size:11pt}a{color:#111}.tag{background:#fff}.print-sheet .note{background:#fff;border:1px solid #aaa}.screen-reader{display:none}}