/* Scene 9 -- "Segmentation -- same machinery, per pixel."

   Layout:
     hero
     sample selector (row of 6 thumbnails)
     U-shape architecture diagram (left enc col / centre bottleneck / right dec col)
     prediction overlay (input | ground truth | prediction)
     class legend
     caption + controls + accuracy footnote */

.s9-root .s9-wrap {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.s9-hero h1 { font-size: 28px; }
.s9-hero .lede em {
  font-style: italic;
  color: var(--ink);
}

/* ---------------------------------------------------------------------------
   Sample selector strip
   --------------------------------------------------------------------------- */

.s9-selector {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 8px 4px;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.s9-selector-label {
  font-size: 12px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-secondary);
  flex: 0 0 auto;
}

.s9-selector-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  flex: 1 1 auto;
}

.s9-thumb {
  background: var(--card-bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 3px;
  cursor: pointer;
  transition: border-color 120ms ease-out, transform 120ms ease-out;
}
.s9-thumb:hover { border-color: var(--ink-secondary); }
.s9-thumb.active {
  border-color: var(--cnn-pos);
  box-shadow: 0 0 0 2px var(--cnn-pos);
  transform: translateY(-1px);
}

.s9-thumb-host { display: block; }
.s9-thumb canvas { display: block; image-rendering: pixelated; }

/* ---------------------------------------------------------------------------
   U-shape architecture diagram
   --------------------------------------------------------------------------- */

.s9-arch {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  grid-template-rows: auto auto auto;
  grid-template-areas:
    "enc1 .    dec1"
    "enc2 .    dec2"
    ".    bot  .";
  gap: 26px 32px;
  padding: 110px 12px 22px;
  background: var(--card-bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
}

.s9-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.s9-col-enc {
  grid-column: 1;
  grid-row: 1 / span 2;
  align-items: flex-start;
  padding-left: 8px;
}
.s9-col-bot {
  grid-column: 2;
  grid-row: 3;
  justify-self: center;
  align-self: end;
}
.s9-col-dec {
  grid-column: 3;
  grid-row: 1 / span 2;
  align-items: flex-end;
  padding-right: 8px;
}

/* Cards (one per U-Net level) */
.s9-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 8px 10px;
  background: var(--bg);
  border: 1px solid var(--rule);
  border-radius: 4px;
  opacity: 0.55;
  transition: opacity 220ms ease-out, border-color 220ms ease-out;
}
.s9-card.s9-visible {
  opacity: 1;
  border-color: var(--ink-secondary);
}

.s9-card-head {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-secondary);
}
.s9-card-name {
  font-weight: 600;
  color: var(--ink);
  font-family: "SF Mono", Menlo, monospace;
  font-size: 11px;
}
.s9-card-sub {
  font-style: italic;
  text-transform: none;
  letter-spacing: 0;
  font-size: 11px;
}

.s9-card-body {
  position: relative;
}
.s9-card-body canvas { display: block; }

/* ---------------------------------------------------------------------------
   Skip + flow arrows (SVG overlay)
   --------------------------------------------------------------------------- */

.s9-arrows {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 2;
  overflow: visible;
}
.s9-arrows svg {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
  /* Always render SVG content above feature-map cards. SVG has no
     z-index by default; without this, in some Chrome versions cards
     with transitions can paint above. */
  isolation: isolate;
}

/* Skip-connection arcs: amber, fade in only when the corresponding decoder
   level is active. */
.s9-skip-path {
  stroke: var(--cnn-accent);
  stroke-width: 4;
  stroke-dasharray: 14 6;
  stroke-linecap: round;
  fill: none;
  opacity: 0;
  /* No transition: in headless rendering the screenshot can fire mid-fade,
     and we want the arc fully drawn at step 6+. The fade was nice-to-have;
     correctness matters more. */
}
:root[data-theme="light"] .s9-skip-path {
  /* Darker amber on cream so the dashes read against the warm light
     background. The default token is too pale at small line widths. */
  stroke: #8d5f1f;
}
#s9-arrow path { fill: var(--cnn-accent); }
:root[data-theme="light"] #s9-arrow path { fill: #8d5f1f; }

.s9-skip-label {
  font-family: "Iowan Old Style", Palatino, Georgia, serif;
  font-style: italic;
  font-size: 14px;
  fill: var(--cnn-accent);
  opacity: 0;
  transition: opacity 220ms ease-out;
}

.s9-arch.s9-skip1-lit .s9-skip1 .s9-skip-path,
.s9-arch.s9-skip1-lit .s9-skip1 .s9-skip-label,
.s9-arch.s9-skip2-lit .s9-skip2 .s9-skip-path {
  opacity: 0.9;
}
.s9-arch.s9-skip1-active .s9-skip1 .s9-skip-path,
.s9-arch.s9-skip2-active .s9-skip2 .s9-skip-path {
  opacity: 1;
  stroke-width: 3;
}

/* Encoder/decoder flow arrows: thinner, ink-coloured, no dashing. */
.s9-down, .s9-up {
  stroke: var(--ink-secondary);
  stroke-width: 1.4;
  fill: none;
  opacity: 0;
  transition: opacity 220ms ease-out;
}
.s9-down-label, .s9-up-label {
  font-family: "Iowan Old Style", Palatino, Georgia, serif;
  font-style: italic;
  font-size: 13px;
  fill: var(--ink-secondary);
  opacity: 0;
  transition: opacity 220ms ease-out;
}

.s9-arch.s9-down1-lit .s9-flow-d1 .s9-down,
.s9-arch.s9-down1-lit .s9-flow-d1 .s9-down-label {
  opacity: 0.85;
}
.s9-arch.s9-down2-lit .s9-flow-d2 .s9-down,
.s9-arch.s9-down2-lit .s9-flow-d2 .s9-down-label {
  opacity: 0.85;
}
.s9-arch.s9-up1-lit .s9-flow-u1 .s9-up,
.s9-arch.s9-up1-lit .s9-flow-u1 .s9-up-label {
  opacity: 0.85;
}
.s9-arch.s9-up2-lit .s9-flow-u2 .s9-up,
.s9-arch.s9-up2-lit .s9-flow-u2 .s9-up-label {
  opacity: 0.85;
}

/* ---------------------------------------------------------------------------
   Prediction overlay panel
   --------------------------------------------------------------------------- */

.s9-overlay {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 18px;
  margin-top: 8px;
}

.s9-ov-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.s9-ov-label {
  font-size: 11px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-secondary);
  font-family: "SF Mono", Menlo, monospace;
}

.s9-ov-host {
  border: 1px solid var(--rule);
  border-radius: 3px;
  padding: 0;
  background: var(--card-bg);
}
.s9-ov-host.s9-visible {
  border-color: var(--ink-secondary);
}
.s9-ov-host canvas { display: block; image-rendering: pixelated; }

/* ---------------------------------------------------------------------------
   Class legend
   --------------------------------------------------------------------------- */

.s9-legend {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  padding: 8px;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

.s9-legend-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.s9-swatch {
  display: inline-block;
  width: 14px;
  height: 14px;
  border-radius: 2px;
  /* The .class-* utility sets `fill`, `stroke`, and `color`. We pull the
     color into background via currentColor so this stays theme-aware. */
  background: currentColor;
  border: 1px solid color-mix(in srgb, currentColor 80%, transparent);
}

.s9-legend-name {
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--ink);
  text-transform: lowercase;
}

/* ---------------------------------------------------------------------------
   Caption / controls / footnote
   --------------------------------------------------------------------------- */

.s9-caption {
  margin: 4px 4px 0;
  text-align: center;
  font-size: 14.5px;
}

.s9-controls {
  margin-top: 6px;
}

.s9-acc-note {
  display: flex;
  justify-content: flex-end;
  align-items: baseline;
  gap: 8px;
  font-size: 11px;
  color: var(--ink-secondary);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}
.s9-acc-value {
  font-family: "SF Mono", Menlo, monospace;
  color: var(--ink);
  font-size: 12px;
  text-transform: none;
  letter-spacing: 0;
}

/* ---------------------------------------------------------------------------
   Responsive: at narrower widths drop into a single-column flow.
   --------------------------------------------------------------------------- */

@media (max-width: 900px) {
  .s9-overlay {
    grid-template-columns: 1fr;
  }
}