@font-face{font-family:LM;src:url('assets/fonts/latin-modern/lmroman10-regular.otf') format('opentype');font-display:swap}@font-face{font-family:LM;src:url('assets/fonts/latin-modern/lmroman12-bold.otf') format('opentype');font-weight:700;font-display:swap}@font-face{font-family:LM;src:url('assets/fonts/latin-modern/lmroman10-italic.otf') format('opentype');font-style:italic;font-display:swap}
/* Root size is relative, so the visitor's own text-size setting enlarges the page (18 px at the browser default). */
:root{--brand:#751a2c;--brand-dark:#5f1524;--ink:#29252a;--muted:#62595f;--line:#e2dadd;--wash:#f7f2f0;--paper:#fffefa;--red:#b3263c;--red-ink:#9d2236;--green:#157064;--green-ink:#12665b;--blue:#2b5eae;--pair:#2a2428;--ok:#166657;--ok-wash:#edf6f2;--bad:#962d34;--bad-wash:#fdf1ef;--info-wash:#eef3fb;font-size:112.5%}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:1rem/1.38 LM,Georgia,serif}a{color:var(--brand)}button,input,select{font:inherit}
button,.button,.file{min-height:2.35rem;border:1px solid #b9a5ac;border-radius:6px;background:#fff;color:var(--brand);padding:.35rem .7rem;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:6px;line-height:1.15}button:hover,.button:hover{background:#f6eff0}button[aria-pressed=true]{background:#efe2e6;border-color:var(--brand);box-shadow:inset 0 -2px var(--brand)}.primary,.button.primary{background:var(--brand);color:#fff;border-color:var(--brand)}.primary:hover,.button.primary:hover{background:var(--brand-dark)}button:disabled{opacity:.4;cursor:default}button:focus-visible,a:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--blue);outline-offset:3px}.quiet{border-color:transparent;background:none;color:var(--brand);text-decoration:underline;text-underline-offset:3px;min-height:2rem;padding:.15rem .35rem}.quiet:hover{background:none;text-decoration-thickness:2px}
h1{font-size:1.62rem;line-height:1.12;margin:0}h3{margin:0}p{margin:0}.muted{color:var(--muted)}
.masthead{max-width:1180px;margin:auto;padding:9px 20px;display:flex;justify-content:space-between;align-items:center;gap:15px;border-bottom:1px solid var(--line)}.brand{display:flex;gap:10px;align-items:center;text-decoration:none;color:var(--ink);font-size:1.12rem}.masthead nav{display:flex;gap:18px;font-size:.84rem}.masthead nav a{white-space:nowrap}main{max-width:1180px;padding:0 20px;margin:auto}
.journey-nav{display:flex;gap:8px;align-items:center;flex-wrap:wrap;padding:9px 0 3px}.journey-nav label{font-size:.84rem;color:var(--muted)}.journey-nav select{min-width:13rem;padding:.25rem .4rem;border:1px solid #c2b0b7;border-radius:6px;background:#fff;color:var(--brand);font-size:.9rem;min-height:2.2rem}#stage-count{font-size:.84rem;color:var(--muted)}.history{margin-left:auto;display:flex;gap:4px}.history button{font-size:.8rem;min-height:2rem;padding:.2rem .55rem;border-color:#d8c9ce}
#lesson-head{padding:5px 0 13px;scroll-margin-top:10px}#lesson-title:focus{outline:none}
/* The context strip is also the legend: what stays fixed, drawn with the same marks as the graph. */
.context-strip{display:flex;flex-wrap:wrap;gap:4px 16px;margin-top:8px;font-size:.84rem;color:var(--muted)}.ctx{display:inline-flex;align-items:center;gap:6px;white-space:nowrap}.ctx i{display:inline-block;width:20px;height:0;border-top:4px solid}.ctx-graph{color:var(--ink)}.ctx-red{color:var(--red-ink)}.ctx-red i{border-color:var(--red)}.ctx-green{color:var(--green-ink)}.ctx-green i{border-top:4px dashed var(--green)}.ctx-obs{color:var(--brand)}.ctx-obs i{width:11px;height:11px;border:0;border-radius:50%;background:var(--brand)}.ctx-pair{color:var(--pair);font-weight:bold}.ctx-pair i{border-color:var(--pair)}
/* Desktop: the figure stays on the left; the right column reads your move → evidence → outcome. Phones: one column in DOM order, controls before the figure. */
.laboratory{display:grid;grid-template-columns:minmax(0,.93fr) minmax(0,1.07fr);grid-template-areas:"figure task" "figure outcome" "figure evidence" "figure assist";grid-template-rows:auto auto auto 1fr;column-gap:30px;row-gap:12px;align-items:start;padding-bottom:10px}
.task-card{grid-area:task;background:var(--wash);border:1px solid #ece3e5;border-radius:10px;padding:11px 14px;display:flex;flex-direction:column;gap:9px;min-width:0}.task-card:focus{outline:none}.graph-pane{grid-area:figure;margin:0;position:sticky;top:8px;min-width:0}#graph .linked-graph{max-height:345px}.evidence{grid-area:evidence;min-width:0}.outcome{grid-area:outcome;display:flex;flex-direction:column;align-items:flex-start;gap:9px;min-width:0}.outcome:has(#feedback:empty):has(#next-action:empty){display:block;height:0;margin-bottom:-12px;overflow:hidden}.assistance{grid-area:assist;border-top:1px solid var(--line);padding-top:9px}
.action-line{font-size:1rem;line-height:1.3}.kicker{display:inline-block;font-size:.68rem;letter-spacing:.09em;text-transform:uppercase;color:var(--brand);font-weight:bold;margin-right:6px;vertical-align:.1em}.ask{font-size:.92rem;margin-right:3px}.answer-pick,.observer-pick,.button-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.dist-row{display:inline-flex;gap:5px;align-items:center;flex-wrap:wrap}button.dist,button.count{min-width:2.45rem;font-variant-numeric:tabular-nums}.unit{font-size:.85rem;color:var(--muted);margin-left:3px}.progress-note{font-size:.84rem;color:var(--muted);margin-left:4px}
/* Vertex identity: a letter in a circle (filled = observer). Distance: a number in a square button. */
.vbadge{width:2.45rem;height:2.45rem;min-height:0;padding:0;border-radius:50%;border:2px solid var(--brand);background:#fff;color:var(--brand);font-weight:bold}.vbadge.is-observer{background:var(--brand);color:#fff}.vbadge.is-observer:hover{background:var(--brand-dark)}.vbadge[aria-pressed=true]{background:var(--brand);box-shadow:0 0 0 3px #fff,0 0 0 5.5px var(--blue)}
.verdict{font-size:.92rem;padding:5px 10px;border-radius:6px;align-self:flex-start}.verdict.ok{background:var(--ok-wash);color:var(--ok)}.verdict.bad{background:var(--bad-wash);color:var(--bad)}.verdict.revealed{background:var(--info-wash);color:#28446e}
.evidence-title,.list-head{font-size:.74rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:normal;margin:0 0 8px}.list-head{margin-top:14px}.list-head span{text-transform:none;letter-spacing:0;font-size:.8rem}
.report-cards{display:flex;gap:10px;flex-wrap:wrap}.report-card{display:flex;flex-direction:column;align-items:center;gap:5px;min-width:4.1rem;padding:8px 12px 7px;border:1px solid #cdbec4;border-radius:8px;background:#fff;color:var(--ink);min-height:5.1rem}.report-who{display:inline-flex;align-items:center;justify-content:center;width:1.8rem;height:1.8rem;border-radius:50%;background:var(--brand);color:#fff;font-size:.88rem;font-weight:bold}.report-who.anonymous{background:none;border:2px dashed #bcb0b5}.report-card strong{font-size:1.6rem;font-weight:normal;line-height:1;font-variant-numeric:tabular-nums}.report-card small{font-size:.62rem;color:#28446e;text-transform:uppercase;letter-spacing:.05em}.report-card.current{border-color:var(--brand);border-width:2px}.traced{border-color:var(--blue)!important;background:var(--info-wash)!important;box-shadow:inset 0 0 0 1px var(--blue)}.wrong{border-color:var(--bad)!important;background:var(--bad-wash)!important}
.trace-caption{border-left:3px solid var(--blue);padding:6px 10px;margin-top:10px;font-size:.88rem;line-height:1.32;background:#f4f7fc}.trace-caption.muted{border-left-color:#ddd3d7;background:none;color:var(--muted);padding:3px 10px}.notation{margin-top:10px;font-size:.95rem}.ms{font-variant-numeric:tabular-nums;white-space:nowrap}
.group-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:8px;align-items:end}.report-group{display:flex;flex-direction:column;align-items:stretch;justify-content:flex-end;padding:6px 3px 0;min-height:9.4rem;border:1px solid #e3d9dc;border-bottom:2px solid #8f8489;border-radius:8px 8px 0 0;background:#fff;color:var(--ink)}.group-stack{display:flex;flex-direction:column-reverse;align-items:center;justify-content:flex-start;gap:3px;min-height:6.3rem}.group-unit{display:block;width:2.4rem;height:1.55rem;border-radius:4px;background:var(--red);border:1px solid #fff}.stack-count{font-size:.85rem;color:var(--red-ink)}.group-axis{display:block;text-align:center;font-weight:bold;font-size:1.1rem;padding:4px 0}.axis-note{font-size:.8rem;color:var(--muted);margin-top:6px}
.chart-legend{display:flex;gap:4px 14px;flex-wrap:wrap;font-size:.8rem;margin:0 0 2px}.key:before{content:'';display:inline-block;width:11px;height:11px;border-radius:2px;margin-right:5px;vertical-align:-1px;background:currentColor}.key.jh-red{color:var(--red-ink)}.key.jh-green{color:var(--green-ink)}.key.jh-ink{color:var(--pair)}.key.jh-ink2{color:#8a7f85}#representation .linked-histogram{max-height:215px}
.named-line{display:flex;align-items:center;flex-wrap:wrap;gap:6px 10px;font-size:.95rem;margin:3px 0}.pair-report{display:inline-flex;align-items:center;gap:4px;font-variant-numeric:tabular-nums}.vmini{display:inline-flex;align-items:center;justify-content:center;width:1.45rem;height:1.45rem;border-radius:50%;background:var(--brand);color:#fff;font-size:.74rem;font-weight:bold}.arrow{color:var(--muted)}.forget{font-size:.9rem;color:var(--muted);margin:3px 0 9px}
/* Edge identity: a code with a line mark that copies the edge's stroke in the graph. */
.edge-chip{display:inline-flex;align-items:center;gap:6px;padding:.18rem .55rem;border:1px solid #d6cbcf;border-radius:999px;background:#fff;color:#3d363a;font-size:.88rem;font-weight:bold;white-space:nowrap;line-height:1.2}.edge-chip:before{content:'';display:inline-block;width:16px;border-top:3px solid #b2a7ac}.edge-chip.red{color:var(--red-ink);border-color:#e4bcc4}.edge-chip.red:before{border-top-color:var(--red)}.edge-chip.green{color:var(--green-ink);border-color:#b8d8d1}.edge-chip.green:before{border-top:3px dashed var(--green)}.edge-chip.pair-a:before{border-top-color:var(--pair)}.edge-chip.pair-b:before{border-top:3px dashed var(--pair)}button.edge-chip{min-height:2.35rem;padding:.2rem .7rem;font-size:.9rem}button.edge-chip:hover{background:#f6eff0}
.records-summary p{font-size:1rem}.records-summary strong{font-size:1.15rem}.delta{font-size:.8rem;color:var(--muted);margin-left:6px;white-space:nowrap}.partition{display:flex;gap:3px;margin-top:7px;height:9px}.seg{border-radius:3px}.seg.shared{background:#6d6268}.seg.own{background:#d5cbcf}
.record-rows{list-style:none;margin:0;padding:0;display:flex;flex-direction:column;gap:6px}.record-row{display:grid;grid-template-columns:6rem 1fr;align-items:center;gap:10px;padding:4px 8px;border-radius:8px;background:#f5f0ee}.record-row .ms{font-size:1.06rem}.row-edges{display:flex;align-items:center;gap:6px;flex-wrap:wrap}.chip-unit{display:inline-flex;align-items:center;gap:6px}.eq{font-size:1.2rem;color:var(--muted)}.own-grid{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(8.6rem,1fr));gap:6px 12px}.own-grid li{display:flex;align-items:center;gap:8px}.none-left{font-size:.92rem;color:var(--ok)}.record-key{font-size:.76rem;color:var(--muted);margin-top:12px}
.inspection{border:2px solid var(--pair);border-radius:10px;padding:10px 12px 8px;background:#fff;scroll-margin-block:12px}.inspection:focus{outline:none}.inspection:focus-visible{outline:3px solid var(--blue);outline-offset:3px}.inspection-head{display:flex;justify-content:space-between;align-items:center;gap:6px 10px;flex-wrap:wrap}.inspection-head h3{font-size:1.08rem}.inspection-head button{font-size:.88rem}#inspection-help{font-size:.84rem;color:var(--muted);margin:4px 0 8px}.records-aside{font-size:.84rem;color:var(--muted);margin-top:8px}
#feedback{font-size:.95rem;line-height:1.36;padding:1px 0 1px 11px;border-left:3px solid #ddd3d7}#feedback.good{border-left-color:var(--ok)}#feedback.revealed{border-left-color:var(--blue)}#feedback:empty{display:none}#next-action:empty{display:none}#next-action button,#next-action>a{white-space:normal;text-align:center;font-size:.98rem;min-height:2.7rem;padding:.45rem 1rem}#next-action p{font-size:.8rem;margin-top:7px;color:var(--muted)}.assistance{display:flex;align-items:center;gap:10px;flex-wrap:wrap}.assistance button{font-size:.8rem;min-height:2rem;padding:.2rem .6rem;border-color:#d8c9ce}.assistance span{font-size:.74rem;color:var(--muted)}
#graph-key{display:flex;justify-content:space-between;align-items:center;gap:6px 10px;flex-wrap:wrap;margin-top:2px;min-height:1.6rem}.graph-key-items{display:flex;flex-wrap:wrap;gap:3px 14px;font-size:.76rem;color:var(--muted)}.k-route:before{content:'━ ';color:var(--blue);font-weight:bold}.k-end:before{content:'◯ ';color:var(--red)}.k-pair:before{content:'━ ';color:var(--pair);font-weight:bold}.k-obs:before{content:'● ';color:var(--brand)}.code-key{width:100%;font-size:.76rem;color:var(--muted);display:flex;align-items:center;gap:2px 8px;flex-wrap:wrap}#codes-toggle{font-size:.78rem}body[data-step="6"] #representation .linked-histogram,.inspection .linked-histogram{max-height:190px}
.explanation,.saved{border-top:1px solid var(--line);padding:12px 0;font-size:.9rem}summary{cursor:pointer;color:var(--brand)}details p{margin:10px 0;max-width:950px}.saved>div{display:flex;gap:8px;flex-wrap:wrap;margin-top:10px}.file{position:relative;overflow:hidden}.file input{position:absolute;inset:0;width:100%;opacity:0;cursor:pointer}#file-status{color:var(--brand);overflow-wrap:anywhere}footer{font-size:.74rem;color:var(--muted);padding:12px 0 24px;line-height:1.5;border-top:1px solid var(--line)}
#list-form{width:100%}#list-form label{font-size:.94rem;margin-bottom:5px;display:block}#list-form>div{display:flex;gap:8px}#list-answer{min-width:0;max-width:420px;flex:1;padding:.4rem .55rem;background:#fff;border:1px solid #ac98a1;border-radius:5px;font-size:.95rem}#list-error{margin:6px 0 0;color:var(--bad);font-size:.88rem;line-height:1.3}#list-answer[aria-invalid="true"]{border-color:var(--bad);box-shadow:inset 0 0 0 1px var(--bad)}.list-result{margin-top:12px}.edge-choice{display:flex;gap:8px;align-items:center;font-size:.92rem;flex-wrap:wrap}.edge-choice select{min-width:0;max-width:330px;padding:.35rem .4rem;border:1px solid #ac98a1;border-radius:5px;font-size:.88rem;background:#fff}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.skip{position:absolute;top:-100px;left:10px;z-index:5}.skip:focus{top:5px;background:#fff;padding:8px}
/* Keep correction feedback and the selected comparison context in view. */
#list-form,#inspection-context,.edge-chip{scroll-margin-block:12px}
@media(min-width:821px) and (max-height:740px){#graph .linked-graph{max-height:290px}.masthead{padding-top:7px;padding-bottom:7px}#lesson-head{padding-bottom:9px}}
@media(max-width:820px){:root{font-size:106.25%}.laboratory{grid-template-columns:minmax(0,1fr);grid-template-areas:"task" "figure" "outcome" "evidence" "assist";grid-template-rows:none;row-gap:10px}.graph-pane{position:static}#graph .linked-graph{max-height:none}.task-card{padding:10px 11px}}
@media(max-width:560px){.masthead{padding:8px 12px;gap:8px}.brand{font-size:1rem;gap:7px}.brand img{width:28px;height:28px}.masthead nav{font-size:.72rem;gap:2px 10px;flex-direction:column;align-items:flex-end}main{padding:0 12px}.journey-nav{gap:5px;padding-top:7px}.journey-nav label{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}.journey-nav select{min-width:0;flex:1 1 11rem;font-size:.84rem}.history button{font-size:.74rem;padding:.15rem .45rem;min-height:2.1rem}#stage-count{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}h1{font-size:1.36rem}#lesson-head{padding:3px 0 9px}.context-strip{gap:3px 12px;font-size:.78rem;margin-top:6px}.report-card{min-width:3.6rem;min-height:4.6rem;padding:6px 9px}.report-card strong{font-size:1.4rem}.group-grid{gap:4px}.report-group{min-height:8rem}.group-stack{min-height:5.4rem}.group-unit{width:1.9rem;height:1.35rem}.record-row{grid-template-columns:5rem 1fr;padding:4px 6px;gap:6px}.own-grid{grid-template-columns:repeat(2,minmax(0,1fr))}#list-form>div{gap:5px}#list-answer{max-width:none}.edge-choice select{flex:1;width:50%}.assistance span{font-size:.7rem}.explanation,.saved{font-size:.85rem}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;animation:none!important;transition:none!important}}

/* Trace feedback keeps breathing room when revealed near a mobile viewport edge. */
.trace-caption{scroll-margin-block:12px}

/* Step 8 states its separate setup and the retained step 7 selection. */
.experiment-context{font-size:.86rem;line-height:1.32;color:var(--muted)}
#next-action{scroll-margin-block:12px}