body{font-size:1.125rem}
:root{--blue:#0868d8;--teal:#087b68;--orange:#af510e;--muted:#606873;--line:#e3e7ec}
[hidden]{display:none!important}
button,input{font:inherit}
button{cursor:pointer}
button:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--color-focus);outline-offset:3px}
button:disabled{cursor:default;opacity:.45}
.skip-link{position:absolute;left:16px;top:-80px;background:white;padding:12px;z-index:5}
.skip-link:focus{top:8px}
.lesson-shell{max-width:1080px;margin:auto;padding:0 28px}
.lesson-header{border-bottom:1px solid var(--line)}
.header-inner{min-height:64px;display:flex;align-items:center;justify-content:space-between;gap:16px;font-size:1.125rem}
.header-inner a{color:var(--muted)}
.lesson-tag{background:#f3f5f7;color:#4d5560;padding:4px 10px;border-radius:5px}
.intro{padding:32px 0 24px}
.eyebrow{font-size:1.125rem;font-weight:600;color:var(--blue);letter-spacing:.06em;margin-bottom:8px}
h1{font-size:clamp(1.5rem,3.2vw,2.125rem);line-height:1.4;letter-spacing:-.04em;margin-bottom:12px}
.intro>p:last-child{max-width:760px;font-size:1.125rem;line-height:1.8}
.steps{list-style:none;display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}
.steps button{display:flex;align-items:center;gap:10px;width:100%;height:100%;text-align:left;border:1px solid var(--line);border-radius:8px;padding:14px 16px;background:white;font-size:1.125rem;color:#4d5560}
.steps button span{font-family:var(--font-mono);color:var(--muted);font-size:1.125rem}
.steps button[aria-current]{background:#edf5ff;border-color:#8fbaef;color:#075cae;font-weight:600}
.steps button[aria-current] span{color:var(--blue)}
.stage-heading{padding:26px 0 18px;max-width:820px}
.stage-heading h2{font-size:1.25rem;line-height:1.5;letter-spacing:-.03em;margin-bottom:8px}
.stage-heading>p:last-child{font-size:1.125rem;line-height:1.8}
.workspace{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,1fr);gap:20px;align-items:start}
.panel{border:1px solid var(--line);border-radius:10px;background:white;min-width:0;overflow:hidden}
.plot-panel{padding:18px 18px 0}
.plot-heading{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:8px}
.plot-heading h3{font-size:1.125rem;letter-spacing:0;line-height:1.5;margin:0}
.plot-heading>span{font-size:1.125rem;color:var(--muted);white-space:nowrap;font-variant-numeric:tabular-nums}
#plot{display:block;width:100%;height:auto;aspect-ratio:1;user-select:none;overflow:visible}
.plot-bg{fill:#fbfcfe;stroke:#dce3ed}
.grid-line{stroke:#e9edf3;stroke-width:1}
.tick{fill:#697480;font-size:1.125rem;font-family:var(--font-mono)}
.axis-title{fill:#465463;font-size:1.125rem;font-weight:600}
#coordinate-guide{fill:none;stroke:var(--blue);stroke-width:1.5;stroke-dasharray:5 4;opacity:.7}
#guides rect{fill:#e7f1ff}
#guides text{fill:#075cae;font-size:1.125rem;font-weight:600;text-anchor:middle;dominant-baseline:middle}
.point{cursor:pointer;outline:none}
.point-hit{fill:transparent}
.point-dot{fill:#7e8a98;stroke:white;stroke-width:2}
.point-halo{fill:none;stroke:transparent;stroke-width:2}
.point-label{font-size:1.125rem;font-weight:600;fill:#475568;paint-order:stroke;stroke:white;stroke-width:4px;stroke-linejoin:round}
.point-a .point-dot{fill:var(--blue)}
.point-a .point-label{fill:var(--blue)}
.point-a.can-drag{cursor:grab;touch-action:none}
.point-a.can-drag:active{cursor:grabbing}
.point[aria-pressed="true"] .point-halo{stroke:#596878}
.point.is-nearest .point-halo{stroke:var(--teal);stroke-dasharray:3 2}
.point.is-compared .point-dot{fill:var(--orange)}
.point.is-compared .point-label{fill:var(--orange)}
.point:focus-visible .point-halo{stroke:var(--blue);stroke-width:3;stroke-dasharray:none}
.comparison-line{stroke:var(--orange);stroke-width:2.5}
.difference-lines{fill:none;stroke:#a5afb9;stroke-width:1.5;stroke-dasharray:5 4}
.plot-help{font-size:1.125rem;color:var(--muted);line-height:1.7;margin:0 0 16px}
.a-controls{border-top:1px solid var(--line);padding:14px 0 10px}
.control-title{display:flex;justify-content:space-between;align-items:center;gap:8px;margin-bottom:10px;font-size:1.125rem}
.a-controls label{display:flex;justify-content:space-between;font-size:1.125rem;margin-top:6px}
.a-controls output{color:var(--blue);font-weight:600;font-variant-numeric:tabular-nums}
.a-controls input{display:block;width:100%;height:28px;accent-color:var(--blue);cursor:pointer}
.scale-note{font-size:1.125rem;color:var(--muted);text-align:right;margin:0}
.detail-panel{padding:20px}
.data-table{width:100%;border-collapse:collapse;font-size:1.125rem;font-variant-numeric:tabular-nums}
.data-table caption{text-align:left;font-size:1.125rem;color:var(--muted);padding-bottom:10px}
.data-table th,.data-table td{padding:9px 10px;text-align:center;border-bottom:1px solid var(--line)}
.data-table thead th{font-size:1.125rem;color:var(--muted);font-weight:500;background:#f8f9fb}
.data-table tbody th{font-weight:600}
.single-table tbody{color:var(--blue);background:#f5f9ff}
.data-table button{border:0;background:transparent;color:inherit;padding:3px 12px;border-radius:4px;text-decoration:underline;text-underline-offset:3px;font-weight:600}
.data-table tr.is-selected{background:#edf5ff;color:#075cae}
.data-table tr.is-unshown{color:#5c6672;background:#fafbfc}
.mapping-arrow{text-align:center;color:#a0b0c2;font-size:1.5rem;padding:8px}
.coordinate-card{padding:16px;text-align:center;background:#f1f7ff;border:1px solid #d6e7fb;border-radius:8px;display:flex;flex-direction:column;gap:6px}
.coordinate-card span{font-size:1.125rem;color:#40566e}
.coordinate-card strong{color:var(--blue);font-family:var(--font-mono);font-size:2rem;line-height:1.3}
.coordinate-card small{font-size:1.125rem;color:var(--muted)}
.takeaway{font-size:1.125rem;line-height:1.9;margin:18px 0 12px}
.subtle{font-size:1.125rem;color:var(--muted);line-height:1.8;margin-bottom:12px}
.reveal-controls{margin-bottom:18px}
.reveal-controls>strong{display:block;font-size:1.125rem;margin-bottom:12px}
.reveal-controls>div{display:flex;align-items:center;flex-wrap:wrap;gap:8px}
.button{border:1px solid var(--blue);background:var(--blue);color:white;padding:9px 13px;display:inline-flex;justify-content:center;align-items:center;border-radius:6px;font-size:1.125rem;font-weight:600;line-height:1.5;min-height:38px;text-decoration:none}
.button:hover{text-decoration:none;filter:brightness(.95)}
.button.secondary{background:white;border-color:#d8dfe7;color:#364454}
.text-button{background:none;border:0;color:var(--blue);padding:6px 0;font-size:1.125rem}
.text-button:hover{text-decoration:underline}
.selected-record{font-size:1.125rem;background:#f4f8fd;border-radius:5px;padding:10px;margin:12px 0 0}
#nearest-heading{font-size:1.125rem;line-height:1.5;letter-spacing:0;margin-bottom:8px}
.ranking{display:flex;flex-direction:column;gap:6px;margin:14px 0}
.rank-button{width:100%;display:grid;grid-template-columns:26px 1fr auto;gap:10px;align-items:center;text-align:left;padding:9px 10px;border:1px solid var(--line);border-radius:6px;background:white;color:#374658}
.rank-button[aria-pressed="true"]{border-color:#d4a478;background:#fff8f1}
.rank-button.is-nearest .rank-id{background:#e0f4ee;color:var(--teal)}
.rank-id{display:grid;place-items:center;width:26px;height:26px;background:#eef1f5;border-radius:50%;font-size:1.125rem;font-weight:600}
.rank-features{display:block;font-size:1.125rem;color:#64717e}
.rank-distance{font-family:var(--font-mono);font-size:1.125rem}
.distance-result{border-top:1px solid var(--line);padding-top:14px;display:grid;grid-template-columns:1fr auto;align-items:center;gap:4px 12px;font-size:1.125rem}
.distance-result strong{font-family:var(--font-mono);font-size:1.8rem;color:var(--orange);line-height:1.3}
.distance-result small{grid-column:1/-1;color:var(--muted);font-size:1.125rem}
details{margin-top:18px;border-top:1px solid var(--line);padding-top:12px}
summary{font-size:1.125rem;cursor:pointer;color:var(--blue);margin-bottom:10px}
details p{font-size:1.125rem;line-height:1.8;margin:0 0 8px}
.formula{font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.learning-note{margin-top:20px;border:1px solid #cde5de;border-radius:8px;background:#f3faf7;padding:20px 24px}
.learning-note h3{font-size:1.125rem;margin-bottom:8px}
.learning-note p{font-size:1.125rem;line-height:1.9;margin-bottom:8px}
.learning-note .subtle{font-size:1.125rem;margin-bottom:0}
.lesson-navigation{display:flex;align-items:center;gap:14px;justify-content:space-between;margin:24px 0}
#stage-status{font-family:var(--font-mono);font-size:1.125rem;color:var(--muted);white-space:nowrap}
.data-note{font-size:1.125rem;color:var(--muted);margin:0 0 32px}
.lesson-footer{border-top:1px solid var(--line);padding-top:22px;padding-bottom:22px;display:flex;justify-content:space-between;gap:16px;font-size:1.125rem;color:var(--muted)}
.notice{padding:16px;border:1px solid var(--line);margin-top:20px}
.header-inner{flex-wrap:wrap;padding-top:12px;padding-bottom:12px}
.control-title{flex-wrap:wrap}
.rank-button{grid-template-columns:30px minmax(0,1fr) auto}
.rank-id{width:30px;height:30px}
.lesson-navigation{flex-wrap:wrap}
@media(max-width:420px){.steps{grid-template-columns:1fr}.steps button{flex-direction:row!important;align-items:center!important;gap:10px!important}.data-table th,.data-table td{padding-left:5px;padding-right:5px}}
@media(max-width:800px){.workspace{grid-template-columns:1fr}.lesson-shell{max-width:620px;padding:0 20px}.intro{padding-top:24px}.plot-panel{padding:16px 14px 0}#plot{max-width:460px;margin:auto}.steps button{flex-direction:column;align-items:flex-start;gap:4px;padding:10px;font-size:1.125rem}.detail-panel{padding:18px}.stage-heading{padding-top:22px}.lesson-footer{padding-top:20px;padding-bottom:20px;flex-wrap:wrap}}
@media(max-width:420px){.lesson-shell{padding-left:16px;padding-right:16px}.lesson-tag{font-size:1.125rem;padding:4px 6px}.header-inner{gap:8px;font-size:1.125rem}.intro>p:last-child{font-size:1.125rem}.steps{gap:6px}.steps button{padding:8px;font-size:1.125rem}.plot-heading>span{font-size:1.125rem}.stage-heading h2{font-size:1.125rem}.lesson-navigation{gap:8px;flex-wrap:wrap}.lesson-navigation .button{font-size:1.125rem;padding:9px 10px}.learning-note{padding:16px}.point-label{font-size:1.125rem}}