:root{--ink:#18213a;--muted:#687081;--blue:#035fa1;--orange:#ff8647;--paper:#f7f6f1;--line:#dde1e6}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 system-ui,-apple-system,sans-serif}button,input{font:inherit}button{cursor:pointer}button:focus-visible,input:focus-visible,a:focus-visible{outline:3px solid var(--orange);outline-offset:4px}header{height:84px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 4vw;background:#fff} .brand{display:flex;align-items:center;gap:14px;font-size:14px;font-weight:650}.brand img{width:45px;height:45px}.caps{text-transform:uppercase;letter-spacing:.15em;font-size:11px;font-weight:750}.header-right{display:flex;align-items:center;gap:24px}.quiet{border:1px solid var(--line);background:transparent;padding:8px 13px;border-radius:6px;color:var(--ink)}main{max-width:1500px;margin:auto;padding:36px 4vw 22px}.intro{display:flex;justify-content:space-between;align-items:end;margin-bottom:28px}.intro h1{font-size:clamp(32px,4vw,52px);font-weight:600;letter-spacing:-.045em;line-height:1.1;margin:10px 0}.intro p{color:var(--muted);margin:10px 0 0;max-width:630px}.badge{font-size:12px;color:var(--blue);background:#e6eef3;padding:7px 12px;border-radius:20px;white-space:nowrap}.workspace{display:grid;grid-template-columns:220px minmax(0,1fr);gap:28px}nav{padding-top:8px}nav button{display:flex;text-align:left;width:100%;gap:12px;border:0;border-left:2px solid var(--line);padding:13px 12px;background:none;color:var(--muted);font-size:13px}nav button.active{border-color:var(--blue);background:#e9eff2;color:var(--blue);font-weight:700}nav span{font-size:11px;opacity:.65}nav .small{margin:22px 8px;color:var(--muted);font-size:12px}.lesson{min-width:0}.lesson-top{display:flex;align-items:start;justify-content:space-between;gap:20px}h2{font-size:28px;letter-spacing:-.035em;margin:4px 0 8px;line-height:1.2}.explain{color:var(--muted);margin:0 0 22px;max-width:820px}.board{background:#fff;border:1px solid var(--line);border-radius:12px;overflow:hidden}.equation{background:var(--ink);color:white;padding:20px 24px;display:flex;justify-content:space-between;align-items:center;gap:18px}.formula{font-family:Georgia,serif;font-size:25px;letter-spacing:.025em}.equation small{color:#bec9de;font:11px system-ui;display:block;margin-bottom:6px}.graph-layout{display:grid;grid-template-columns:minmax(0,1fr) 245px}.graph{padding:15px 14px 0;min-width:0}svg{width:100%;height:auto;display:block}.legend{display:flex;gap:18px;flex-wrap:wrap;font-size:11px;color:var(--muted);padding:0 14px 12px}.dot{display:inline-block;width:8px;height:8px;background:var(--blue);border-radius:50%;margin-right:5px}.orange{background:var(--orange)}.controls{padding:23px 20px;border-left:1px solid var(--line);background:#fbfcfd}.control{margin-bottom:20px}.control label{display:flex;justify-content:space-between;font-size:12px;font-weight:650;gap:10px}.control small{font-size:11px;color:var(--muted);display:block;margin:4px 0}input[type=range]{width:100%;accent-color:var(--blue);margin:10px 0 0}input[type=number]{width:70px;border:1px solid var(--line);border-radius:4px;padding:4px;color:var(--ink)}.primary{border:0;background:var(--blue);color:#fff;padding:11px 16px;border-radius:6px;font-size:12px;font-weight:650;width:100%}.secondary{margin-top:9px;width:100%;font-size:12px}.stats{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid var(--line)}.stat{padding:17px 23px;border-right:1px solid var(--line)}.stat:last-child{border:0}.stat small{display:block;font-size:10px;color:var(--muted);text-transform:uppercase;letter-spacing:.07em}.stat strong{font-size:24px;font-weight:600}.stat em{font-size:11px;font-style:normal;color:var(--muted)}.under{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-top:18px}.insight,.prompt{padding:20px 23px;border:1px solid var(--line);border-radius:9px;background:#fff;font-size:13px}.prompt{background:#eeeee6}.under p{margin:7px 0 0}.under .caps{font-size:10px;color:var(--blue)}details{margin-top:18px;border-top:1px solid var(--line);padding-top:14px;font-size:13px}summary{cursor:pointer;font-weight:650}table{width:100%;border-collapse:collapse;font-size:12px;margin-top:14px;text-align:right}th,td{border-bottom:1px solid var(--line);padding:8px}th:first-child,td:first-child{text-align:left}.table-scroll{overflow-x:auto;max-height:320px}.bottom{display:flex;justify-content:space-between;align-items:center;margin:24px 0}.bottom button{padding:10px 18px;border:1px solid var(--line);border-radius:6px;background:#fff;color:var(--ink)}.bottom button:last-child{background:var(--ink);color:#fff}.bottom button:disabled{opacity:.35;cursor:default}.progress{font-size:12px;color:var(--muted)}footer{margin:20px 0 10px;color:var(--muted);font-size:11px;border-top:1px solid var(--line);padding-top:18px}.source{max-width:900px}.present header,.present .intro,.present nav,.present footer{display:none}.present main{padding-top:22px}.present .workspace{grid-template-columns:1fr}.present .graph-layout{grid-template-columns:minmax(0,1fr) 260px}.present #exit{display:block!important}#exit{display:none;position:fixed;top:8px;right:10px;z-index:4}.notice{font-size:11px;color:var(--muted);padding-top:14px}.toggle{display:flex;gap:8px;font-size:12px;align-items:center;margin:13px 0}.next-map{line-height:1.8}.status{font-size:11px;margin-top:10px;color:var(--blue);min-height:18px}@media(max-width:1050px){.workspace{grid-template-columns:175px minmax(0,1fr);gap:18px}.graph-layout{grid-template-columns:1fr}.controls{border-left:0;border-top:1px solid var(--line);display:grid;grid-template-columns:1fr 1fr;gap:15px}.control{margin-bottom:3px}.present .graph-layout{grid-template-columns:1fr}}@media(max-width:700px){header{height:70px}.header-right .caps{display:none}.intro{display:block}.badge{display:inline-block;margin-top:16px}.workspace{display:block}nav{display:flex;overflow-x:auto;margin:0 0 22px}nav button{min-width:145px;border-left:0;border-bottom:2px solid var(--line);padding:10px}nav .small{display:none}.under{grid-template-columns:1fr}.equation{display:block}.formula{font-size:21px}.stats .stat{padding:12px}.stat strong{font-size:20px}h2{font-size:25px}.controls{padding:18px}.intro h1{font-size:38px}.lesson-top .badge{display:none}}@media(prefers-reduced-motion:no-preference){button{transition:background .15s}}@media print{header,nav,.controls,.bottom,#exit{display:none!important}.workspace{display:block}.graph-layout{display:block}details{display:block}body{background:white}}
.dataset-bar{display:flex;align-items:center;justify-content:space-between;gap:20px;background:#eaf0f3;border:1px solid #d6e0e7;border-radius:8px;padding:14px 20px;margin-bottom:24px;font-size:12px}.dataset-bar .caps{font-size:9px;color:var(--blue)}.dataset-bar label{display:flex;align-items:center;gap:10px;font-size:11px;white-space:nowrap}select{font:inherit;color:var(--ink);padding:8px;border:1px solid #c4d0da;border-radius:5px;background:white;max-width:100%}select:disabled{opacity:.65}.stats{grid-template-columns:repeat(4,1fr)}.stat strong{font-size:21px}.control label{align-items:center}.control input[type=number]{width:85px;font-size:12px;padding:5px}.step-ref{font-size:11px;color:var(--blue);margin:12px 0}.model-callout{background:#eaf0f3;border-radius:6px;padding:12px 16px;font-size:12px;margin-top:12px}.fit-banner{padding:8px 14px;background:#edf4f9;color:var(--blue);font-size:11px}.graph .legend{min-height:42px}.present .dataset-bar{margin-top:20px}.present #chapter{margin-right:170px}.exact{color:var(--blue);font-weight:650}.selected-row{background:#fff0e4}.graph-caption{color:var(--muted);font-size:11px;padding:0 14px 12px}.axis-note{font-size:11px;color:var(--muted)}nav{max-height:85vh;overflow-y:auto;position:sticky;top:15px;align-self:start}nav button{padding:10px 12px}.reference-row{background:#eaf0f3}#modelOutput table{min-width:650px}@media(max-width:700px){.dataset-bar{display:block}.dataset-bar label{margin-top:12px;display:block}.dataset-bar select{display:block;margin-top:5px}.stats{grid-template-columns:repeat(2,1fr)}.stat:nth-child(2){border-right:0}.stat:nth-child(-n+2){border-bottom:1px solid var(--line)}nav{position:static;max-height:none;overflow-y:hidden}.control input[type=number]{width:75px}.formula{overflow-wrap:anywhere}.present .dataset-bar{margin-top:35px}}@media print{.dataset-bar label{display:none}}
.dataset-bar{display:block}.data-heading{margin-bottom:14px}.data-selectors{display:grid;grid-template-columns:1fr 1fr 1fr;gap:20px}.dataset-bar .data-selectors label{display:flex;flex-direction:column;align-items:stretch;gap:6px;white-space:normal;font-size:12px}.data-selectors small{font-size:10px;color:var(--muted)}.data-selectors input[type=number]{width:100%;padding:8px;border:1px solid #c4d0da;border-radius:5px;background:white}.sample-note{margin:12px 0 0;font-size:11px;color:var(--muted)}.calculation{padding:16px 20px;background:#eef3f6;border-top:1px solid var(--line);font-size:14px}.calculation p{margin:4px 0}.line-note{font-size:11px;color:var(--muted);margin:8px 0}.formula{font-size:23px}.stats{grid-template-columns:repeat(3,1fr)}.present .intro{display:none}.present .dataset-bar{padding:10px 16px}.present .data-heading{margin-bottom:8px}.present .sample-note{margin-top:6px}.present .data-selectors{gap:14px}.present .data-selectors label{margin:0}@media(max-width:700px){.data-selectors{grid-template-columns:1fr}.dataset-bar .data-selectors label{margin:0}.stats{grid-template-columns:repeat(2,1fr)}.formula{font-size:20px}}
.participant-picker{border-top:1px solid #cfdce5;padding-top:12px;margin-top:12px}.participant-chips{display:flex;flex-wrap:wrap;gap:7px;margin-top:9px}.participant-chips button{min-width:34px;padding:6px 9px;background:#fff;color:var(--muted);border:1px solid #bdcbd6;border-radius:5px;font-size:12px}.participant-chips button[aria-pressed=true]{background:var(--blue);color:white;border-color:var(--blue)}.intro-stages{display:flex;gap:8px;flex-wrap:wrap;margin:0 0 18px}.intro-stages button{border:1px solid var(--line);background:white;border-radius:5px;padding:8px 13px;font-size:12px;color:var(--muted)}.intro-stages button[aria-pressed=true]{color:var(--blue);border-color:var(--blue);background:#edf4f9}[data-inspect]{cursor:pointer}[data-inspect]:focus-visible{outline:3px solid var(--orange);outline-offset:2px}svg [data-inspect]:focus-visible{outline:none}svg [data-inspect]:focus-visible circle:last-of-type{stroke:var(--orange);stroke-width:4}.intro-definition{font-family:Georgia,serif;font-size:20px}.selected-row{background:#fff0e4}.click-instruction{font-size:11px;color:var(--muted);margin:8px 0}.selected-details{padding:10px 12px;border-radius:5px;background:#fff0e4;margin-top:12px;font-size:12px}.present .participant-picker{padding-top:8px;margin-top:8px}.present .participant-chips button{padding:3px 7px;min-width:30px}#dataPicker[hidden],#introStages[hidden]{display:none!important}
.term-picker{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}.term-picker button{padding:7px 11px;border:1px solid #b9cbd9;background:white;color:var(--ink);border-radius:5px;font-size:12px}.term-picker button[aria-pressed=true]{background:var(--blue);border-color:var(--blue);color:white}.model-note{font-size:12px;line-height:1.6;color:var(--muted);margin:10px 0}.advanced .controls{font-size:12px}.advanced .controls>label{display:block;margin:0 0 16px}.advanced .controls select{display:block;width:100%;margin-top:6px}.advanced .controls input[type=number]{width:100%;margin-top:5px}.advanced .controls .toggle{display:flex;align-items:center;margin:10px 0}.advanced .controls .term-picker{margin-bottom:14px}.advanced .stats{grid-template-columns:repeat(4,minmax(0,1fr))}.advanced .stat{padding:14px 16px}.advanced .stat strong{font-size:20px;overflow-wrap:anywhere}.analysis-error{padding:18px;background:#fff2e9;border:1px solid #f2c8ab;border-radius:6px;margin:12px 0;line-height:1.6}.code-formula{display:block;margin-top:8px;font-family:ui-monospace,monospace;font-size:11px;overflow-wrap:anywhere}.groups{display:flex;gap:7px;flex-wrap:wrap;margin:10px 0}.groups button{padding:6px 9px;border:1px solid #b6c8d7;background:white;border-radius:4px;font-size:11px}.groups button[data-group="0"]{border-color:#035fa1;color:#035fa1}.groups button[data-group="1"]{border-color:#e17b3c;color:#a84c17}.groups button[data-group="2"]{border-color:#8265ad;color:#70518f}.section-label{font-size:10px;text-transform:uppercase;letter-spacing:.12em;color:var(--muted);margin:14px 10px 4px}.advanced [hidden],.data-selectors label[hidden],#modelTerms[hidden]{display:none!important}.scroll-table{overflow-x:auto}.advanced #outputTable{max-height:530px}.result-note{padding:12px 15px;background:#edf3f6;border-radius:5px;font-size:12px;margin-top:12px}.term-caption{display:block;font-size:10px;letter-spacing:.06em;margin-top:14px;color:var(--muted);text-transform:uppercase}.plot-hint{font-size:11px;color:var(--muted);padding:8px 14px}#week8Link{font-size:12px;padding:7px 12px;white-space:nowrap}.header-right{gap:12px}@media(max-width:700px){.advanced .stats{grid-template-columns:repeat(2,minmax(0,1fr))}.advanced .stat:nth-child(2){border-right:0}.header-right #week8Link{font-size:10px;padding:7px}.brand{font-size:11px}.header-right{gap:5px}.header-right .caps{display:none}.graph-layout{grid-template-columns:1fr}}

/* R-backed controls preserve the existing teaching layout. */
.engine-status{font-size:12px;margin:0 0 18px;padding:11px 14px;border:1px solid #ccdce7;border-radius:7px;background:#edf4f9;color:var(--blue);display:flex;justify-content:space-between;align-items:center;gap:12px}.engine-status[data-state=error]{background:#fff2e9;color:#8a421c;border-color:#efc9b0}.engine-status button{font-size:11px}.data-selectors input,.controls input[type=number]{font:inherit}.advanced .controls label.toggle{display:flex}.controls label.toggle input{width:auto;margin:0}.controls fieldset{border:0;padding:0;margin:0 0 17px;min-width:0}.controls legend{font-size:12px;font-weight:650;margin-bottom:7px}.controls .toggle{font-size:12px}.advanced .controls .toggle{display:flex}.control label{display:block}.controls input[type=range]{padding:0}.quiet:disabled,.primary:disabled{opacity:.5;cursor:wait}.upload-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px;padding:12px 0}.upload-grid label{display:block;white-space:normal}.upload-grid input{font:inherit;font-size:11px;max-width:100%;margin-top:8px}h3{font-size:14px;font-weight:650;margin:22px 0 5px}pre{white-space:pre;overflow:auto;max-height:450px;background:#eef3f6;border:1px solid var(--line);border-radius:6px;padding:16px;font:11px/1.6 ui-monospace,monospace}.downloads{display:flex;flex-wrap:wrap;gap:9px;margin-top:13px}.downloads button,.downloads a{font-size:12px}.downloads a{color:var(--blue)}.analysis-pending{opacity:.5;pointer-events:none}.result-table{overflow:auto;max-height:450px}.table-scroll{max-height:450px}.formula{overflow-wrap:anywhere}.legend{min-height:40px}.meta-note{font-size:11px;color:var(--muted)}.sr-only{position:absolute;width:1px;height:1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.advanced .stats{grid-template-columns:repeat(4,minmax(0,1fr))}.advanced .stat strong{font-size:20px}.advanced .controls input[type=number]{width:100%}.advanced .controls select{width:100%}.controls button+button{margin-top:8px}.data-selectors>label input{width:100%}.download-note{font-size:12px;color:var(--muted)}@media(max-width:700px){.upload-grid{grid-template-columns:1fr}.engine-status{align-items:start}.advanced .stats{grid-template-columns:repeat(2,minmax(0,1fr))}.header-right #week8Link{font-size:10px}.brand{max-width:190px}.formula{font-size:19px}.controls{display:block}.controls>label{margin-bottom:16px}}
.analysis-actions{display:flex;gap:12px;align-items:end;flex-wrap:wrap;margin:16px 0}.analysis-actions label{min-width:240px}.analysis-actions p{flex-basis:100%;margin:0;color:var(--muted);font-size:13px}.primary{background:var(--blue,#035fa1);color:#fff;border:0;border-radius:8px;padding:11px 18px;font-weight:650;cursor:pointer}.primary:disabled{opacity:.5;cursor:not-allowed}.profile-legend{font-size:12px;text-align:center;padding:8px;line-height:1.7}.brand{gap:12px}.intro h1{max-width:800px}.controls select{max-width:100%}.engine-status{min-height:44px}

.foundation-context{margin:18px 0 22px;padding:0 0 0 16px;border-left:3px solid var(--blue);font-size:14px;line-height:1.6}.foundation-context p{margin:6px 0}.foundation-context[hidden]{display:none}