.lesson-visuals { margin: 48px 0; padding-top: 32px; border-top: 1px solid var(--line); }
.visual-section-heading { max-width: 720px; margin-bottom: 32px; }
.visual-section-heading h2 { font-size: 24px; line-height: 1.5; margin-bottom: 16px; }
.visual-section-heading > p:last-child { color: var(--muted); font-size: 16px; }
.visual-photo-layout { display: grid; grid-template-columns: minmax(0,1.2fr) minmax(0,1fr); gap: 32px; align-items: start; }
.lesson-visual-figure { margin: 0; min-width: 0; background: var(--surface); border: 1px solid var(--line); border-radius: 16px; overflow: hidden; }
.visual-kind { padding: 12px 24px; color: var(--muted); background: var(--wash); font-size: 12px; font-weight: 600; }
.visual-media { background: var(--wash); min-width: 0; }
.visual-media img { display: block; width: 100%; height: auto; max-height: 440px; object-fit: contain; }
.visual-media img[hidden] { display: none; }
.visual-media svg { display: block; width: 100%; height: auto; }
.visual-media-tools { display: flex; align-items: center; justify-content: space-between; gap: 8px; padding: 4px 16px; border-block: 1px solid var(--line); }
.visual-media-tools button { min-height: 44px; padding: 8px; border: 0; background: transparent; font: inherit; font-size: 14px; color: var(--muted); cursor: pointer; }
.visual-media-tools button:hover { color: var(--blue); background: var(--blue-soft); }
.visual-media-tools button:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.visual-enlarge { display: flex; gap: 12px; align-items: center; }
.visual-enlarge:hover { background: var(--blue-soft); }
.lesson-visual-figure figcaption { padding: 24px; }
.lesson-visual-figure h3 { margin: 0 0 12px; font-size: 20px; line-height: 1.5; }
.lesson-visual-figure figcaption > p { font-size: 16px; line-height: 1.85; }
.lesson-visual-figure figcaption > .visual-photo-note { margin-top: 16px; font-size: 14px; color: var(--muted); }
.visual-attribution { margin-top: 20px; padding-top: 16px; border-top: 1px solid var(--line); color: var(--muted); }
.visual-attribution p { margin: 4px 0; font-size: 12px; line-height: 1.8; overflow-wrap: anywhere; }
.visual-attribution a { color: var(--blue); text-decoration: underline; text-underline-offset: 3px; display: inline-block; padding-block: 8px; }
.visual-new-window { font-size: 12px; }
.visual-observe { padding: 24px 0; }
.visual-observe h3 { font-size: 24px; line-height: 1.5; }
.visual-observe ol,.visual-reading-steps { padding: 0; list-style: none; }
.visual-observe li { display: flex; align-items: start; gap: 16px; padding: 20px 0; border-bottom: 1px solid var(--line); }
.visual-step-number { flex: 0 0 32px; display: inline-grid; place-items: center; width: 32px; height: 32px; background: var(--blue-soft); color: var(--blue); font-size: 14px; border-radius: 8px; font-weight: 600; }
.visual-observe li p { font-size: 16px; line-height: 1.85; }
.visual-teaching-note { font-size: 14px; color: var(--muted); margin-top: 24px; line-height: 1.8; }
.visual-diagram,.visual-generated { margin-top: 32px; }
.visual-diagram > .visual-media { padding: 0; }
.visual-diagram > figcaption { max-width: 800px; padding-block: 24px 20px; }
.visual-diagram > figcaption h3 { font-size: 24px; letter-spacing: -.02em; }
.visual-diagram-summary { color: var(--muted); }
.visual-reading-steps { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 24px; margin: 0; padding: 24px; }
.visual-reading-steps li { display: flex; align-items: start; gap: 12px; }
.visual-reading-steps h4 { font-size: 16px; margin: 4px 0 12px; line-height: 1.5; }
.visual-reading-steps p { font-size: 14px; line-height: 1.85; color: var(--muted); }
.visual-generated .visual-kind { background: var(--blue-soft); color: var(--blue); }
.visual-generated .visual-media img { max-height: 640px; }
.visual-image-error { padding: 40px 24px; color: var(--muted); font-size: 16px; line-height: 1.8; }
.visual-viewer { box-sizing: border-box; width: calc(100vw - 32px); max-width: 1600px; height: calc(100dvh - 32px); max-height: none; margin: auto; padding: 0; border: 1px solid var(--line); border-radius: 16px; color: var(--ink); background: var(--surface); overflow: hidden; }
.visual-viewer[open] { display: flex; flex-direction: column; }
.visual-viewer::backdrop { background: rgb(32 43 49 / 80%); }
.visual-viewer-header { display: flex; justify-content: space-between; align-items: center; gap: 16px; padding: 16px 24px; border-bottom: 1px solid var(--line); }
.visual-viewer-header h2 { font-size: 20px; line-height: 1.5; margin: 0; }
.visual-viewer-kind { margin: 0 0 4px; color: var(--muted); font-size: 12px; line-height: 1.6; }
.visual-viewer-header .button { flex-shrink: 0; min-height: 44px; }
.visual-viewer-tools { display: flex; align-items: center; gap: 8px; padding: 8px 24px; flex-wrap: wrap; }
.visual-viewer-tools button { min-width: 64px; min-height: 44px; border: 0; border-radius: 8px; color: var(--ink); background: var(--wash); font: inherit; font-size: 14px; cursor: pointer; }
.visual-viewer-tools button[aria-pressed=true] { background: var(--blue-soft); color: var(--blue); font-weight: 700; }
.visual-viewer-tools span { color: var(--muted); font-size: 12px; margin-left: 8px; }
.visual-viewer-scroll { flex: 1; min-height: 0; overflow: auto; background: var(--wash); overscroll-behavior: contain; }
.visual-viewer-content { min-width: 100%; width: 100%; }
.visual-viewer-content .visual-media img { max-height: none; }
.visual-viewer-header,.visual-viewer-tools { flex-shrink: 0; }
.visual-zoom-region { max-width: 100%; overflow-x: auto; overflow-y: hidden; }
.visual-zoom-region > :is(.diagram-comparison-scenes,.visual-media) { width: var(--visual-scale,100%); }
.visual-zoom-region:focus-visible { outline: 3px solid var(--blue); outline-offset: -3px; }
.visual-viewer[data-comparison-layout=stacked] [data-diagram-compare=true] .diagram-comparison-scenes { grid-template-columns: minmax(0,1fr); }
.visual-viewer[data-comparison-layout=stacked] .diagram-comparison-pane + .diagram-comparison-pane { border-left: 0; border-top: 1px solid var(--line); }
@media(max-width:800px) {
  .visual-photo-layout { grid-template-columns: minmax(0,1fr); gap: 8px; }
  .visual-observe { padding: 24px 0; }
  .visual-reading-steps { grid-template-columns: minmax(0,1fr); }
  .visual-diagram > .visual-media { padding: 0; }
}
@media(max-width:600px) {
  .lesson-visuals { margin: 32px 0; padding-top: 24px; }
  .lesson-visual-figure figcaption,.visual-reading-steps { padding: 20px; }
  .visual-kind,.visual-enlarge { padding-inline: 20px; }
  .visual-viewer { width: calc(100vw - 16px); height: calc(100dvh - 16px); border-radius: 8px; }
  .visual-viewer-header { padding: 12px 16px; gap: 8px; }
  .visual-viewer-header h2 { font-size: 16px; }
  .visual-viewer-tools { padding: 8px 16px; }
  .visual-viewer-tools span { margin: 0; flex-basis: 100%; }
  .visual-viewer-tools { gap: 8px; }
  .visual-viewer-tools button { min-width: 60px; }
  .diagram-live-control select { font-size: 16px; }
}
.visual-image-box { position: relative; margin-inline: auto; width: 100%; }
.visual-image-box img { max-height: none; }
.visual-generated .visual-image-box img { max-height: none; }
.visual-hotspots { position: absolute; inset: 0; pointer-events: none; }
.visual-hotspot { position: absolute; transform: translate(-50%,-50%); pointer-events: auto; width: 44px; height: 44px; padding: 0; display: grid; place-items: center; border: 0; border-radius: 50%; background: transparent; cursor: pointer; }
.visual-hotspot-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--ink); box-shadow: 0 0 0 2px var(--surface); }
.visual-hotspot[aria-pressed=true] .visual-hotspot-dot { background: var(--blue); box-shadow: 0 0 0 1.5px var(--surface), 0 0 0 2.5px var(--blue); }
.visual-hotspot:hover .visual-hotspot-dot { background: var(--blue); }
.visual-hotspots[hidden] { display: none; }
.visual-part-chips button[aria-pressed=true],.visual-motion-stages button[aria-pressed=true] { background: var(--blue-soft); color: var(--blue); font-weight: 700; }
.visual-image-failed .visual-hotspots { display: none; }
.visual-exploration { padding: 24px; }
.visual-parts-hint { font-size: 14px; color: var(--muted); margin: 0 0 12px; }
.visual-part-chips,.visual-motion-actions,.visual-motion-stages { display: flex; flex-wrap: wrap; gap: 8px; }
.visual-part-chips button,.visual-motion button { min-height: 44px; border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; background: var(--surface); color: var(--ink); font: inherit; font-size: 14px; cursor: pointer; }
.visual-part-chips button:hover,.visual-motion button:hover { background: var(--wash); }
.visual-part-chips button span { margin-right: 4px; color: var(--muted); font-size: 12px; font-variant-numeric: tabular-nums; }
.visual-part-explanation { margin-top: 16px; padding: 20px; background: var(--wash); border-radius: 8px; }
.visual-part-explanation h4 { margin: 0 0 16px; font-size: 20px; line-height: 1.5; }
.visual-part-explanation dl { margin: 0; }
.visual-part-explanation dt { margin: 16px 0 4px; font-size: 14px; font-weight: 700; }
.visual-part-explanation dd { margin: 0; font-size: 16px; line-height: 1.85; }
.visual-practice-link { display: inline-flex; align-items: center; min-height: 44px; gap: 8px; margin-top: 16px; color: var(--blue); font-size: 14px; text-decoration: underline; text-underline-offset: 3px; }
.visual-motion { margin-top: 24px; padding-top: 24px; border-top: 1px solid var(--line); }
.visual-motion-actions { align-items: center; }
.visual-motion [data-motion-play] { display: inline-flex; align-items: center; justify-content: center; gap: 8px; min-width: 112px; color: var(--surface); background: var(--blue); border: 0; font-weight: 700; }
.visual-motion [data-motion-play]:hover { background: var(--blue); filter: brightness(.92); }
.visual-motion [data-motion-play]::before { content: ''; width: 12px; height: 12px; background: currentColor; clip-path: polygon(15% 0,100% 50%,15% 100%); }
.visual-motion[data-playing=true] [data-motion-play]::before { clip-path: polygon(0 0,35% 0,35% 100%,0 100%,0 0,65% 0,100% 0,100% 100%,65% 100%,65% 0); }
.visual-motion [data-motion-reset] { border: 0; background: transparent; color: var(--muted); }
.visual-motion-actions label { display: flex; align-items: center; flex: 1 1 160px; gap: 12px; min-width: 0; font-size: 14px; }
.visual-motion input { width: 100%; min-width: 0; min-height: 44px; accent-color: var(--blue); }
.visual-motion-position { font-size: 12px; font-variant-numeric: tabular-nums; color: var(--muted); white-space: nowrap; }
.visual-motion-stages { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); margin-top: 16px; gap: 4px; padding: 4px; background: var(--wash); border-radius: 8px; }
.visual-motion-stages button { display: flex; align-items: center; gap: 12px; text-align: left; border: 0; background: transparent; min-width: 0; }
.visual-motion-stages button[aria-pressed=true] { background: var(--surface); color: var(--ink); }
.visual-stage-index { font-size: 12px; font-variant-numeric: tabular-nums; color: var(--muted); }
.visual-motion-stages button[aria-pressed=true] .visual-stage-index { color: var(--blue); font-weight: 700; }
.visual-motion-story { display: grid; grid-template-columns: minmax(0,1fr) minmax(160px,.4fr); gap: 24px; align-items: start; padding: 20px 0 0; }
.visual-motion-observation { margin: 0 0 8px; font-size: 16px; font-weight: 700; line-height: 1.6; }
.visual-motion-description,.visual-reduced-note { font-size: 14px; line-height: 1.85; margin: 0; color: var(--muted); }
.visual-reduced-note { margin-top: 12px; }
.visual-motion-reference { display: grid; gap: 8px; padding-left: 20px; border-left: 1px solid var(--line); }
.visual-motion-reference > span { color: var(--muted); font-size: 12px; }
.visual-motion-metric { font-size: 16px; line-height: 1.6; font-weight: 600; font-variant-numeric: tabular-nums; }
.visual-motion button:disabled { cursor: default; opacity: .55; }
.visual-exploration button:focus-visible,.visual-hotspot:focus-visible,.visual-practice-link:focus-visible,.visual-motion input:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.visual-viewer-content .visual-image-box { max-width: none !important; }
.visual-viewer-content .lesson-visual-figure { border: 0; border-radius: 0; }
.visual-viewer-content .visual-exploration { max-width: 800px; }
@media(max-width:600px) {
  .visual-exploration { padding: 20px; }
  .visual-part-explanation { padding: 16px; }
}
.visual-exploration > .visual-motion:first-child { margin-top: 0; padding-top: 0; padding-bottom: 24px; margin-bottom: 24px; border-top: 0; border-bottom: 1px solid var(--line); }
.visual-photo-layout { display: block; }
.visual-photo-figure { display: grid; grid-template-columns: minmax(0,1.2fr) minmax(0,1fr); align-items: start; }
.visual-photo-figure > .visual-kind { grid-column: 1 / -1; }
.visual-photo-figure > .visual-media { grid-column: 1; grid-row: 2; }
.visual-photo-figure > .visual-media-tools { grid-column: 1; grid-row: 3; }
.visual-photo-figure > .visual-exploration { grid-column: 2; grid-row: 2 / 5; }
.visual-photo-figure > figcaption { grid-column: 1; grid-row: 4; }
.visual-photo-figure > .visual-observe { grid-column: 1 / -1; padding: 24px; border-top: 1px solid var(--line); }
.visual-photo-figure .visual-observe ol { display: grid; grid-template-columns: repeat(3,minmax(0,1fr)); gap: 24px; }
.visual-viewer-content .visual-photo-figure { display: block; }
@media(max-width:800px) {
  .visual-photo-figure { display: flex; flex-direction: column; align-items: stretch; }
  .visual-photo-figure .visual-observe ol { display: block; }
}
.visual-motion-actions label { white-space: nowrap; }
.diagram-live-controls { display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1fr); gap: 32px; padding: 24px; background: var(--wash); border-block: 1px solid var(--line); }
.diagram-live-playback { margin: 0; padding: 0 24px 20px; border: 0; }
.visual-diagram { overflow: clip; }
.diagram-workbench { min-width: 0; border-block: 1px solid var(--line); }
.diagram-stage { min-width: 0; background: var(--surface); }
.diagram-workbench .diagram-live-controls { border: 0; }
.diagram-link-notice { padding: 12px; border-left: 3px solid var(--orange); background: var(--surface); font-size: 14px; line-height: 1.75; }
@media(min-width:1000px) {
  .diagram-workbench { display: grid; grid-template-columns: minmax(0,1fr) clamp(320px,28%,360px); align-items: start; }
  .diagram-stage { position: sticky; top: 100px; }
  .diagram-workbench .diagram-live-controls { grid-template-columns: minmax(0,1fr); padding: 20px; gap: 24px; border-left: 1px solid var(--line); }
  .visual-viewer-content .diagram-stage { top: 16px; }
}
@media(max-width:600px) and (min-height:700px) {
  .diagram-stage { position: sticky; top: 0; z-index: 2; background: var(--surface); }
  .diagram-workbench .diagram-live-controls :is(input,select,button,summary) { scroll-margin-top: 420px; }
}
.diagram-live-playback button { min-height: 44px; border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; background: var(--surface); color: var(--ink); font: inherit; font-size: 14px; cursor: pointer; }
.diagram-live-playback [data-motion-play] { min-width: 112px; color: var(--surface); background: var(--blue); font-weight: 700; }
.diagram-live-playback button:disabled { opacity: .55; cursor: default; }
.diagram-live-playback input { width: 100%; min-width: 0; min-height: 44px; accent-color: var(--blue); }
.diagram-live-playback :is(button,input):focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.diagram-live-controls h4 { font-size: 20px; line-height: 1.5; margin: 4px 0 16px; }
.diagram-live-presets { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 20px; }
.diagram-live-presets button { min-height: 44px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 8px; background: var(--surface); color: var(--ink); font: inherit; font-size: 14px; cursor: pointer; }
.diagram-live-presets button[aria-pressed=true] { color: var(--blue); border-color: var(--blue); background: var(--blue-soft); }
.diagram-live-control { display: block; margin-top: 16px; font-size: 14px; }
.diagram-live-control > span:first-child { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.diagram-live-control output { font-weight: 700; color: var(--blue); font-variant-numeric: tabular-nums; }
.diagram-live-control input,.diagram-live-control select { display: block; width: 100%; min-width: 0; min-height: 44px; accent-color: var(--blue); }
.diagram-live-control select { margin-top: 8px; padding: 8px; border: 1px solid var(--line); border-radius: 8px; background: var(--surface); color: var(--ink); font: inherit; }
.diagram-live-bounds { display: flex; justify-content: space-between; gap: 8px; font-size: 12px; color: var(--muted); }
.diagram-live-metrics { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 16px; margin: 12px 0 20px; }
.diagram-live-metrics dt { color: var(--muted); font-size: 12px; }
.diagram-live-metrics dd { margin: 4px 0 0; font-size: 24px; font-weight: 700; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; }
.diagram-live-metrics small { font-size: 12px; font-weight: 400; }
.diagram-live-result { padding: 16px; background: var(--surface); border-left: 3px solid var(--blue); border-radius: 8px; }
.diagram-live-result p,.diagram-live-note,.diagram-live-controls details p { font-size: 14px; line-height: 1.75; margin: 8px 0 0; }
.diagram-live-note { color: var(--muted); }
.diagram-live-controls details { margin-top: 16px; font-size: 14px; }
.diagram-live-controls summary,.visual-reading-reference summary { cursor: pointer; min-height: 44px; align-content: center; }
.diagram-live-controls :is(input,select,button,summary):focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.visual-reading-reference { padding: 0 24px 24px; }
.diagram-comparison-toolbar { display: flex; flex-wrap: wrap; gap: 8px; padding: 16px 20px 0; }
.diagram-comparison-toolbar button { min-height: 44px; padding: 8px 12px; border: 0; border-radius: 8px; background: var(--wash); color: var(--ink); font: inherit; font-size: 14px; cursor: pointer; }
.diagram-comparison-toolbar [data-diagram-compare][aria-pressed=true] { background: var(--blue); color: var(--surface); }
.diagram-comparison-toolbar button:hover { filter: brightness(.96); }
.diagram-comparison-toolbar button:focus-visible { outline: 3px solid var(--blue); outline-offset: 3px; }
.diagram-comparison-status,.diagram-comparison-legend { margin: 8px 20px 12px; color: var(--muted); font-size: 13px; line-height: 1.65; }
.diagram-comparison-scenes { display: grid; grid-template-columns: minmax(0,1fr); }
[data-diagram-compare=true] .diagram-comparison-scenes { grid-template-columns: repeat(2,minmax(0,1fr)); }
.diagram-comparison-pane { min-width: 0; }
[data-diagram-compare=true] .diagram-comparison-pane + .diagram-comparison-pane { border-left: 1px solid var(--line); }
.diagram-comparison-pane-label { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 12px; padding: 12px 16px; background: var(--wash); font-size: 14px; }
.diagram-comparison-pane-label span { font-size: 12px; color: var(--muted); }
.diagram-before-media svg { display: block; width: 100%; height: auto; }
.diagram-comparison-panel { padding: 24px; border-bottom: 1px solid var(--line); }
.diagram-comparison-details { display: grid; gap: 24px; }
.diagram-comparison-details h4 { margin: 0 0 12px; font-size: 20px; line-height: 1.5; }
.diagram-comparison-inputs ul { display: flex; flex-wrap: wrap; gap: 12px 32px; padding: 0; margin: 0; list-style: none; }
.diagram-comparison-inputs li { display: grid; gap: 6px; font-size: 14px; line-height: 1.65; }
.diagram-comparison-inputs li span { font-variant-numeric: tabular-nums; }
.diagram-comparison-details mark,.diagram-live-control.is-comparison-changed output { background: #fff0a8; color: var(--ink); border-radius: 3px; padding: 1px 4px; box-decoration-break: clone; -webkit-box-decoration-break: clone; }
.diagram-comparison-table { min-width: 0; }
.diagram-comparison-table table { width: 100%; border-collapse: collapse; table-layout: fixed; font-size: 15px; line-height: 1.7; font-variant-numeric: tabular-nums; }
.diagram-comparison-table caption { text-align: left; font-size: 14px; margin-bottom: 12px; color: var(--muted); }
.diagram-comparison-table :is(th,td) { text-align: left; vertical-align: top; padding: 12px 16px; border-bottom: 1px solid var(--line); word-break: keep-all; overflow-wrap: anywhere; }
.diagram-comparison-table thead { background: var(--wash); }
.diagram-comparison-table tbody th { font-weight: 500; }
.diagram-comparison-table .comparison-delta { color: var(--muted); }
.diagram-comparison-table .is-changed .comparison-delta { color: var(--orange); font-weight: 700; }
.diagram-comparison-explanation { max-width: 82ch; }
.diagram-comparison-explanation ul { display: grid; gap: 12px; padding-left: 24px; margin: 0; }
.diagram-comparison-explanation li,.diagram-comparison-takeaway,.diagram-comparison-empty { font-size: 16px; line-height: 1.85; }
.diagram-comparison-takeaway { margin: 20px 0 0; padding: 16px 20px; border-radius: 8px; background: var(--wash); }
.diagram-comparison-takeaway strong { display: block; margin-bottom: 4px; }
.diagram-comparison-empty { margin: 0; color: var(--muted); }
.diagram-stage [hidden],.diagram-comparison-panel[hidden] { display: none; }
@media(max-width:600px) {
  .diagram-comparison-toolbar { gap: 4px; padding: 12px 12px 0; }
  .diagram-comparison-toolbar button { padding-inline: 8px; font-size: 12px; }
  .diagram-comparison-status,.diagram-comparison-legend { margin-inline: 12px; font-size: 12px; }
  .diagram-comparison-pane-label { display: grid; gap: 4px; padding: 8px 12px; }
  .diagram-comparison-panel { padding: 20px 16px; }
  .diagram-comparison-table table { font-size: 13px; }
  .diagram-comparison-table :is(th,td) { padding: 10px 6px; }
  .diagram-comparison-takeaway { padding: 16px; }
}
@media(max-width:800px) { .diagram-live-controls { grid-template-columns: minmax(0,1fr); gap: 24px; padding: 20px; } }
@media(max-width:600px) {
  .visual-motion-actions { gap: 8px; }
  .visual-motion-actions label { flex-basis: calc(100% - 64px); }
  .visual-motion-stages button { flex-direction: column; align-items: start; gap: 4px; padding: 8px; font-size: 12px; }
  .visual-motion-story { grid-template-columns: minmax(0,1fr); gap: 12px; }
  .visual-motion-reference { padding: 0; border: 0; display: flex; align-items: baseline; gap: 12px; }
  .visual-motion-reference > span { flex-shrink: 0; }
}