:root{--paper:#f6f2e9;--card:#fffdf8;--ink:#18323e;--muted:#53636b;--teal:#155e59;--pale:#dfede7;--rust:#993f26;--line:#c6cdc8;--focus:#a33720;--amber:#6b3b13;--amber-bg:#fff0d9}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.55 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}a{color:var(--teal);text-underline-offset:3px}button,input,select,textarea{font:inherit}button,a,input,select,summary,textarea{-webkit-tap-highlight-color:transparent}button{min-height:44px;cursor:pointer;border:1px solid transparent;border-radius:6px;padding:10px 16px;font-weight:650;background:var(--card);color:var(--ink)}button:disabled{cursor:default}button:hover{filter:brightness(.95)}:focus-visible{outline:3px solid var(--focus);outline-offset:4px;box-shadow:0 0 0 2px var(--paper)}input,select,textarea{color:var(--ink);background:#fff;border:1px solid #7c8c8e;border-radius:5px;padding:10px;min-height:44px;width:100%;max-width:100%}textarea{resize:vertical;min-height:100px}label{font-weight:600;display:block}label input,label select{margin-top:5px}input[type=checkbox],input[type=radio]{width:20px;height:20px;min-height:20px;flex:0 0 20px;accent-color:var(--teal);margin:3px 0 0}.primary{background:var(--teal);color:#fff}.secondary{background:var(--card);border-color:var(--teal);color:var(--teal)}.quiet{border-color:var(--line);background:transparent;font-weight:550}.danger{background:var(--rust);color:white}.full{width:100%}.skip{position:absolute;top:-80px;left:12px;background:white;padding:12px;z-index:5}.skip:focus{top:12px}.masthead{border-bottom:1px solid var(--line);background:var(--card)}.masthead-inner{max-width:1220px;margin:auto;padding:18px 24px;display:flex;align-items:center;justify-content:space-between;gap:18px}.brand{display:flex;gap:12px;align-items:center;color:var(--ink);text-decoration:none;letter-spacing:.1em;font-size:13px;font-weight:800}.brand small{display:block;font-size:11px;font-weight:500;letter-spacing:.01em;color:var(--muted);margin-top:2px}.brand-mark{display:grid;place-items:center;background:var(--ink);color:var(--paper);width:44px;height:44px;font-family:Georgia,serif;font-size:21px;letter-spacing:-1px;flex:0 0 44px}.guide-link{font-size:13px;white-space:nowrap;padding:8px 0}.shell{max-width:1220px;padding:30px 24px 64px;margin:auto;display:grid;grid-template-columns:238px minmax(0,1fr);gap:40px}.rail{position:sticky;top:20px;align-self:start}.case-label{font-size:11px;font-weight:800;letter-spacing:.1em;margin:5px 0 20px}.case-label span{display:block;color:var(--teal);margin-top:3px}.steps{display:grid;gap:8px}.steps button{text-align:left;display:flex;gap:10px;align-items:flex-start;border-color:transparent;padding:12px 10px;background:transparent;font-size:14px;position:relative}.steps button[aria-current=step]{background:var(--ink);color:#fff}.steps small{display:block;font-size:11px;font-weight:450;line-height:1.5;color:var(--muted)}.steps [aria-current=step] small{color:#d9e6e4}.step-number{font-family:Georgia,serif;font-size:18px;color:var(--teal)}[aria-current=step] .step-number{color:#f4d39c}.saved-label{font-size:10px;position:absolute;right:10px;bottom:3px;color:var(--teal)}[aria-current=step] .saved-label{color:#f4d39c}.progress-text{font-size:12px;color:var(--muted);margin:22px 0 5px}progress{width:100%;height:7px;accent-color:var(--teal)}.rail-note{border-top:1px solid var(--line);margin:24px 0;padding-top:18px;font-size:13px}.rail-note p{margin:6px 0;color:var(--muted)}.reset-box{margin-top:18px;font-size:12px}.reset-box summary{padding:8px 0}.reset-box button{font-size:12px}.eyebrow{font-size:11px;letter-spacing:.12em;font-weight:800;color:var(--teal);margin:8px 0 12px}h1{font-family:Georgia,"Times New Roman",serif;font-size:clamp(32px,4.1vw,49px);font-weight:500;line-height:1.12;letter-spacing:-.025em;margin:0 0 18px;max-width:760px}h2{font-family:Georgia,"Times New Roman",serif;font-size:25px;line-height:1.25;font-weight:500;margin:0 0 14px}.lead{font-size:17px;line-height:1.6;color:var(--muted);max-width:730px;margin:0 0 24px}p{margin:0 0 14px}.intro-art{height:170px;background:var(--pale);border:1px solid var(--line);position:relative;overflow:hidden;margin:30px 0}.paper-plane{position:absolute;left:12%;top:30px;width:120px;height:90px;background:var(--teal);clip-path:polygon(0 20%,100% 0,65% 100%,48% 56%);transform:rotate(-7deg)}.paper-plane:after{content:"";position:absolute;width:100%;height:100%;background:var(--paper);clip-path:polygon(48% 56%,100% 0,59% 69%)}.intro-stamp{position:absolute;right:8%;top:38px;border:2px solid var(--rust);padding:12px 18px;color:var(--rust);font-weight:800;line-height:1.15;letter-spacing:.11em;transform:rotate(6deg);font-size:16px}.chart-lines{position:absolute;bottom:0;left:38%;right:0;height:46px;display:flex;gap:15px;align-items:end;opacity:.35}.chart-lines i{display:block;width:15px;height:22px;background:var(--teal)}.chart-lines i:nth-child(2){height:30px}.chart-lines i:nth-child(3){height:26px}.chart-lines i:nth-child(4){height:35px}.chart-lines i:nth-child(5){height:39px}.intro-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.intro-grid article{border-top:2px solid var(--teal);padding-top:12px}.intro-grid p{font-size:14px;color:var(--muted);margin-top:6px}.privacy{background:#e8eee8;border-left:3px solid var(--teal);padding:14px 16px;font-size:14px;margin:22px 0}.small{font-size:13px;color:var(--muted);margin-top:10px}.metric-row{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin:20px 0}.metric{padding:13px 14px;border:1px solid var(--line);border-radius:6px;background:var(--card)}.metric strong{font-size:26px;display:block;font-variant-numeric:tabular-nums;line-height:1.2}.metric span{display:block;color:var(--muted);font-size:12px;margin-top:7px}.two-charts{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:18px;margin:22px 0}.chart-card{margin:0;background:var(--card);border:1px solid var(--line);padding:16px 12px;border-radius:8px;min-width:0}.chart-card figcaption{padding:0 6px;margin-bottom:5px}.chart-card figcaption strong{display:block;font-size:14px}.chart-card figcaption span{display:block;font-size:12px;color:var(--muted);margin-top:3px}.chart-card a{font-size:12px;display:inline-block;margin:5px 6px}.chart-card svg{display:block;width:100%;height:auto;overflow:visible}.chart-card svg text{font-family:system-ui,sans-serif;fill:var(--ink);font-size:15px}.chart-card .quiet{margin:4px 6px}.chart-card .choice{margin:0 6px;font-size:13px}.control-card,.practice-card{border:1px solid var(--line);padding:21px;border-radius:8px;background:var(--card);margin:20px 0}.field-grid{display:grid;grid-template-columns:1fr 1fr;gap:16px}.field-grid.three{grid-template-columns:1.6fr .8fr .8fr}.field-grid label{font-size:13px}.button-row{display:flex;flex-wrap:wrap;gap:10px;margin-top:16px}.control-card .small{margin-bottom:0}.data-details{border-top:1px solid var(--line);margin:15px 0;padding-top:4px}summary{cursor:pointer;min-height:44px;padding:10px 0;font-weight:600;font-size:14px}.data-region{max-width:100%;max-height:360px;overflow:auto;margin:10px 0;border:1px solid var(--line);border-radius:4px}table{border-collapse:collapse;width:100%;background:var(--card);font-size:13px}caption{text-align:left;padding:10px;font-weight:650;background:var(--pale)}th,td{padding:9px 11px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}th{font-weight:650}thead th{background:#eef2ed;position:sticky;top:0}tbody 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14px;font-size:11px;margin:0 6px}.legend-pop:before,.legend-sample:before{content:"";display:inline-block;width:11px;height:11px;margin-right:5px;border:1px solid var(--ink);background:#acbdbb}.legend-sample:before{background:repeating-linear-gradient(45deg,#155e59,#155e59 3px,#e5f1eb 3px,#e5f1eb 5px)}.segmented{display:flex;flex-wrap:wrap;gap:10px}.segmented legend{width:100%}.segmented label{font-size:13px;display:flex;gap:8px;align-items:center;border:1px solid var(--line);padding:9px 12px;border-radius:5px;min-height:44px}.segmented input{margin:0}.next-row{text-align:right;margin-top:26px}.headline-card{padding:24px;background:var(--ink);color:var(--paper);border-radius:8px}.headline-card .eyebrow{color:#d8e9e2}.headline-card h2{font-size:31px;line-height:1.2}.headline-card p:last-child{font-size:14px;margin:0;color:#e0e7e4}.assembled{font-size:15px;background:var(--pale);padding:15px;border-radius:5px;margin:16px 0}.own-conclusion{margin-top:20px;border-top:1px solid var(--line);padding-top:7px}.own-conclusion label{font-size:14px}.notebook-entry{background:var(--card);padding:20px;border:1px solid var(--line);border-radius:7px;margin:14px 0}.notebook-entry h2{font-size:22px}.notebook-entry p{font-size:14px;white-space:pre-wrap}.notebook-entry .small{color:var(--muted)}.follow-up{margin-top:28px}.lesson-footer{font-size:11px;border-top:1px solid var(--line);padding-top:22px;margin-top:38px;color:var(--muted)}.lesson-footer a{display:block;margin-top:5px}.visually-hidden{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}[hidden]{display:none!important}main:focus{outline:none}.guide-page{max-width:900px;margin:auto;padding:32px 24px}.guide-page h1{margin-top:25px}.guide-page h2{margin-top:30px}.guide-page li{margin-bottom:9px}.guide-page code{font-size:13px;overflow-wrap:anywhere}.guide-page a{overflow-wrap:anywhere}
@media(max-width:900px){.shell{grid-template-columns:195px minmax(0,1fr);gap:24px;padding:24px 18px}.steps button{font-size:12px}.steps small{font-size:10px}.step-number{font-size:16px}.two-charts{grid-template-columns:1fr}.field-grid.three{grid-template-columns:1fr 1fr}.field-grid.three label:first-child{grid-column:1/-1}.intro-grid{grid-template-columns:1fr}.intro-grid article{padding-top:8px}.intro-grid p{margin:3px 0 5px}.brand small{font-size:10px}.sampling-layout,.correlation-layout{grid-template-columns:1fr}}
@media(max-width:620px){.masthead-inner{padding:14px 16px;gap:12px;flex-wrap:wrap}.brand{font-size:11px;gap:8px}.brand small{font-size:10px;letter-spacing:0}.brand-mark{width:36px;height:36px;flex-basis:36px;font-size:18px}.guide-link{font-size:12px}.shell{display:block;padding:18px 16px 40px}.rail{position:static}.case-label{margin:0 0 10px;font-size:10px}.case-label span{display:inline;margin-left:9px}.steps{grid-template-columns:1fr 1fr;gap:6px;margin-bottom:12px}.steps button{padding:11px 8px;font-size:12px;gap:6px;min-height:67px;border-color:var(--line)}.steps small{font-size:10px;line-height:1.35}.saved-label{bottom:2px;right:7px;font-size:9px}.rail-note{display:none}.progress-text{margin-top:10px}.rail .full{margin-top:11px}.reset-box{margin:4px 0 24px}.reset-box summary{min-height:34px}.lead{font-size:16px}.eyebrow{font-size:10px;line-height:1.6}h1{font-size:35px}.metric-row{gap:7px}.metric{padding:12px 8px}.metric strong{font-size:22px}.metric span{font-size:11px}.two-charts{margin:18px 0;gap:14px}.control-card,.practice-card{padding:16px}.field-grid{grid-template-columns:1fr}.field-grid.three{grid-template-columns:1fr 1fr;gap:10px}.field-grid label{font-size:13px}.button-row>*{flex:1 1 auto}.choice{font-size:14px}.chart-card{padding:14px 8px}.chart-card svg text{font-size:16px}.insight-card{padding:18px}.headline-card{padding:20px}.headline-card h2{font-size:29px}.intro-art{height:145px;margin:20px 0}.paper-plane{left:8%;width:88px;height:70px;top:35px}.intro-stamp{font-size:13px;right:6%;top:35px;padding:11px}.next-row button{width:100%}.data-region{max-height:300px}.guide-page{padding:20px 16px}}
@media(prefers-reduced-motion:reduce){*,*:before,*:after{animation:none!important;transition:none!important;scroll-behavior:auto!important}}

.notebook-entry p,.assembled,.feedback,.privacy{overflow-wrap:anywhere}.guide-link{min-height:44px;display:inline-flex;align-items:center}.brand{min-height:44px}

@media(max-width:900px){.field-grid:not(.three){grid-template-columns:1fr}}