/* ==========================================================================
   Black Holes directory and comparison view
   ========================================================================== */

.bh-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(245px, 1fr));
  gap: 12px;
  margin: 24px 0;
}

.bh-grid-toggle {
  display: block;
  width: fit-content;
  margin: 0 auto;
  padding: 9px 16px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 12px;
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.bh-grid-toggle:hover,
.bh-grid-toggle:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  background: var(--surface-strong);
  color: var(--text);
}

.bh-grid-toggle[hidden] {
  display: none;
}

.bh-grid-note {
  margin: 0 0 14px;
  color: var(--text-dim);
  font-size: 11px;
  line-height: 1.55;
}

.bh-card {
  display: grid;
  gap: 10px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.2s ease;
}

.bh-card.is-collapsed {
  display: none;
}

.bh-card:hover {
  border-color: color-mix(in srgb, var(--bh-accent, var(--accent)) 42%, var(--line));
  background: var(--surface-strong);
  transform: translateY(-2px);
}

.bh-card-main {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 12px;
  align-items: center;
  color: inherit;
  text-decoration: none;
}

.bh-glyph {
  position: relative;
  justify-self: center;
  width: var(--glyph-size, 38px);
  height: var(--glyph-size, 38px);
  border-radius: 50%;
  background:
    radial-gradient(circle at 50% 50%, #05060a 0 34%, color-mix(in srgb, var(--bh-accent) 88%, #fff) 37%, color-mix(in srgb, var(--bh-accent) 58%, transparent) 54%, transparent 74%);
  box-shadow: 0 0 calc(var(--glyph-size, 38px) * 0.5) color-mix(in srgb, var(--bh-accent) 34%, transparent);
  transition: filter 0.2s ease, box-shadow 0.2s ease;
}

.bh-card:hover .bh-glyph {
  filter: brightness(1.18);
  box-shadow: 0 0 calc(var(--glyph-size, 38px) * 0.66) color-mix(in srgb, var(--bh-accent) 52%, transparent);
}

.bh-card-copy strong {
  display: block;
  color: var(--text);
  font-size: 13.5px;
  font-weight: 600;
  line-height: 1.25;
}

.bh-card-copy span {
  display: block;
  margin-top: 4px;
  color: var(--text-dim);
  font-size: 9px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-card-copy small {
  display: block;
  margin-top: 3px;
  color: var(--text-soft);
  font-size: 11px;
  line-height: 1.45;
}

.bh-compare {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  width: fit-content;
  padding: 5px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-soft);
  font-size: 10.5px;
  cursor: pointer;
  user-select: none;
}

.bh-compare:hover,
.bh-compare:has(input:checked) {
  border-color: color-mix(in srgb, var(--bh-accent, var(--accent)) 50%, var(--line));
  color: var(--text);
}

.bh-compare input {
  accent-color: var(--bh-accent, var(--accent));
  width: 13px;
  height: 13px;
  margin: 0;
}

.bh-compare-panel {
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.bh-compare-head {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 10px;
}

.bh-compare-head h2 {
  margin: 0;
  color: var(--text);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.bh-compare-head p {
  margin: 4px 0 0;
  color: var(--text-soft);
  font-size: 12px;
  line-height: 1.6;
}

.bh-compare-actions {
  display: flex;
  gap: 7px;
}

.bh-compare-actions button {
  padding: 7px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 10.5px;
  cursor: pointer;
}

.bh-compare-actions button:hover,
.bh-compare-actions button:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  color: var(--text);
}

.bh-compare-hint {
  margin: 10px 0 0;
  color: var(--text-dim);
  font-size: 12px;
  line-height: 1.6;
}

.bh-compare-wrap {
  margin-top: 14px;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.bh-compare-table {
  width: 100%;
  min-width: 620px;
  border-collapse: collapse;
  font-size: 11.5px;
}

.bh-compare-table th,
.bh-compare-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.bh-compare-table thead th {
  color: var(--text-dim);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  white-space: nowrap;
}

.bh-compare-table thead th:first-child,
.bh-compare-table tbody th {
  position: sticky;
  left: 0;
  z-index: 1;
  min-width: 120px;
  background: var(--surface-strong);
}

.bh-compare-table tbody th {
  color: var(--text-dim);
  font-size: 9.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  white-space: nowrap;
}

.bh-compare-table tbody td {
  color: var(--text-soft);
  line-height: 1.5;
}

.bh-compare-table tbody tr:last-child th,
.bh-compare-table tbody tr:last-child td {
  border-bottom: 0;
}

.bh-compare-table a {
  color: var(--accent);
  text-decoration: none;
}

.bh-compare-table a:hover {
  text-decoration: underline;
}

.bh-page-link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  margin-top: 18px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text-soft);
  font-size: 11px;
  text-decoration: none;
}

.bh-page-link:hover {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  color: var(--text);
}

.bh-compare-toast {
  position: fixed;
  left: 50%;
  bottom: 18px;
  z-index: 1200;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  max-width: min(92vw, 560px);
  padding: 10px 12px 10px 16px;
  border: 1px solid color-mix(in srgb, var(--accent) 42%, var(--line));
  border-radius: 14px;
  background: color-mix(in srgb, var(--surface-strong) 94%, transparent);
  box-shadow: 0 14px 40px rgba(0, 0, 0, 0.45);
  color: var(--text);
  transform: translateX(-50%);
  backdrop-filter: blur(14px) saturate(1.1);
}

.bh-compare-toast[hidden] {
  display: none;
}

.bh-compare-toast-text {
  flex: 1 1 auto;
  min-width: 0;
  color: var(--text-soft);
  font-size: 12px;
  line-height: 1.45;
}

.bh-compare-toast-action {
  flex: none;
  padding: 8px 12px;
  border: 1px solid color-mix(in srgb, var(--accent) 55%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent) 16%, transparent);
  color: var(--text);
  font: inherit;
  font-size: 11px;
  font-weight: 600;
  cursor: pointer;
}

.bh-compare-toast-action:hover,
.bh-compare-toast-action:focus-visible {
  background: color-mix(in srgb, var(--accent) 24%, transparent);
}

.bh-compare-toast-close {
  flex: none;
  width: 28px;
  height: 28px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: transparent;
  color: var(--text-soft);
  font-size: 15px;
  line-height: 1;
  cursor: pointer;
}

.bh-compare-toast-close:hover,
.bh-compare-toast-close:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  color: var(--text);
}

@media (max-width: 700px) {
  .bh-grid {
    grid-template-columns: 1fr;
  }

  .bh-compare-table {
    min-width: 540px;
  }

  .bh-compare-toast {
    bottom: 12px;
    gap: 8px;
    padding: 10px 12px;
  }

  .bh-compare-toast-text {
    flex: 1 1 100%;
  }
}

/* ==========================================================================
   Anatomy of a black hole (interactive diagram)
   ========================================================================== */

.bh-section-head {
  margin: 34px 0 18px;
}

.bh-section-head .eyebrow {
  margin-bottom: 8px;
}

.bh-section-head h2 {
  margin: 0;
  color: var(--text);
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.bh-section-lede {
  max-width: 680px;
  margin: 9px 0 0;
  color: var(--text-soft);
  font-size: 13.5px;
  line-height: 1.75;
}

.bh-anatomy-layout {
  display: block;
}

.bh-anatomy-figure {
  margin: 0;
  padding: 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(120% 90% at 50% 42%, #101527 0%, #080a12 58%, #05060c 100%);
  overflow: hidden;
}

.bh-anatomy-svg {
  display: block;
  width: 100%;
  height: auto;
}

.bh-anatomy-svg .bh-part {
  cursor: pointer;
  transition: opacity 0.22s ease;
}

.bh-anatomy-svg .bh-part:hover {
  filter: brightness(1.22) saturate(1.08);
}

.bh-anatomy-svg.is-dimmed .bh-part,
.bh-anatomy-svg.is-dimmed .bh-label {
  opacity: 0.16;
}

.bh-anatomy-svg.is-dimmed .bh-part.is-active,
.bh-anatomy-svg.is-dimmed .bh-label.is-active {
  opacity: 1;
}

.bh-anatomy-svg .bh-label {
  pointer-events: none;
  transition: opacity 0.22s ease;
}

.bh-anatomy-svg .bh-label path {
  fill: none;
  stroke: rgba(255, 255, 255, 0.34);
  stroke-width: 1;
}

.bh-anatomy-svg .bh-label-title {
  fill: rgba(242, 242, 248, 0.92);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0;
}

.bh-anatomy-svg .bh-label-sub {
  fill: rgba(242, 242, 248, 0.52);
  font-size: 10.5px;
}

.bh-anatomy-detail {
  display: grid;
  grid-template-columns: minmax(0, 0.42fr) minmax(0, 0.58fr);
  gap: 16px;
  align-items: start;
  margin-top: 16px;
}

.bh-anatomy-info {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.bh-anatomy-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}

.bh-anatomy-chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 11px;
  cursor: pointer;
  transition: border-color 0.18s ease, color 0.18s ease, background 0.18s ease;
}

.bh-anatomy-chip:hover {
  border-color: color-mix(in srgb, var(--accent) 45%, var(--line));
  color: var(--text);
}

.bh-anatomy-chip.is-active {
  border-color: color-mix(in srgb, var(--chip, var(--accent)) 62%, var(--line));
  background: color-mix(in srgb, var(--chip, var(--accent)) 14%, var(--surface));
  color: var(--text);
}

.bh-anatomy-chip-dot {
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  border-radius: 50%;
  box-shadow: 0 0 8px color-mix(in srgb, var(--chip, var(--accent)) 65%, transparent);
}

.bh-anatomy-copy {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.bh-anatomy-copy h3 {
  margin: 0 0 7px;
  color: var(--text);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.bh-anatomy-copy p {
  margin: 0;
  color: var(--text-soft);
  font-size: 12.5px;
  line-height: 1.7;
}

.bh-anatomy-hint {
  margin: 0;
  color: var(--text-dim);
  font-size: 11px;
  line-height: 1.6;
}

/* ==========================================================================
   Compare their scale (log overview + size/mass explorer)
   ========================================================================== */

.bh-scale {
  margin-top: 10px;
}

/* --------------------------------------------------------------------------
   True-size zoom camera
   -------------------------------------------------------------------------- */

.bh-zoom {
  margin-top: 18px;
}

.bh-zoom-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 12px;
}

.bh-zoom-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}

.bh-zoom-play,
.bh-zoom-reset {
  appearance: none;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 34px;
  padding: 7px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 10.5px;
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.bh-zoom-play {
  border-color: color-mix(in srgb, var(--accent) 42%, var(--line));
  background: color-mix(in srgb, var(--accent) 12%, var(--surface));
  color: var(--text);
}

.bh-zoom-play:hover,
.bh-zoom-reset:hover,
.bh-zoom-play:focus-visible,
.bh-zoom-reset:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 62%, var(--line));
  background: color-mix(in srgb, var(--accent) 17%, var(--surface-strong));
  color: var(--text);
  outline: none;
}

.bh-zoom-play.is-playing {
  border-color: color-mix(in srgb, var(--accent) 70%, var(--line));
  background: color-mix(in srgb, var(--accent) 20%, var(--surface-strong));
}

.bh-zoom-play-icon {
  width: 0;
  height: 0;
  flex: 0 0 auto;
  border-top: 4.5px solid transparent;
  border-bottom: 4.5px solid transparent;
  border-left: 7px solid currentColor;
}

.bh-zoom-play.is-playing .bh-zoom-play-icon {
  width: 8px;
  height: 9px;
  border: 0;
  background: linear-gradient(90deg, currentColor 0 2px, transparent 2px 6px, currentColor 6px 8px);
}

.bh-zoom-fov {
  color: var(--text-soft);
  font-size: 10.5px;
  letter-spacing: 0;
  font-variant-numeric: tabular-nums;
}

.bh-zoom-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(255px, 0.38fr);
  gap: 12px;
  align-items: stretch;
}

.bh-zoom-stage-wrap {
  position: relative;
  min-width: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(circle at 21% 27%, rgba(186, 211, 255, 0.18) 0 1px, transparent 1.6px),
    radial-gradient(circle at 73% 18%, rgba(186, 211, 255, 0.14) 0 1px, transparent 1.5px),
    radial-gradient(circle at 82% 68%, rgba(186, 211, 255, 0.12) 0 1px, transparent 1.5px),
    radial-gradient(circle at 36% 79%, rgba(186, 211, 255, 0.1) 0 1px, transparent 1.5px),
    radial-gradient(120% 100% at 50% 48%, #11182a 0%, #080b14 56%, #04060b 100%);
  cursor: zoom-in;
}

.bh-zoom-stage-wrap::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(65% 62% at 50% 50%, transparent 38%, rgba(2, 4, 9, 0.4) 100%);
  pointer-events: none;
}

.bh-zoom-stage {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: auto;
}

.bh-zoom-fill {
  fill: #020409;
  opacity: 0.92;
  pointer-events: none;
  transition: opacity 0.18s ease;
}

.bh-zoom-fill.is-selected {
  opacity: 1;
}

.bh-zoom-fill.is-dimmed {
  opacity: 0.42;
}

.bh-zoom-glow {
  fill: none;
  stroke-width: 13;
  opacity: 0.15;
  transition: opacity 0.2s ease;
}

.bh-zoom-glow.is-selected {
  opacity: 0.46;
}

.bh-zoom-glow.is-dimmed {
  opacity: 0.025;
}

.bh-zoom-ring {
  fill: none;
  stroke-width: 1.7;
  opacity: 0.82;
  transition: opacity 0.18s ease, stroke-width 0.18s ease;
}

.bh-zoom-ring.is-selected {
  stroke-width: 3.2;
  opacity: 1;
}

.bh-zoom-ring.is-dimmed {
  opacity: 0.14;
}

.bh-zoom-label {
  pointer-events: none;
  transition: opacity 0.2s ease;
}

.bh-zoom-label.is-dimmed {
  opacity: 0.16;
}

.bh-zoom-leader {
  fill: none;
  stroke: rgba(225, 233, 252, 0.28);
  stroke-width: 1;
  stroke-dasharray: 2 4;
}

.bh-zoom-label.is-selected .bh-zoom-leader {
  stroke: var(--acc);
  opacity: 0.8;
}

.bh-zoom-label-name,
.bh-zoom-label-size {
  paint-order: stroke;
  stroke: #060811;
  stroke-linejoin: round;
}

.bh-zoom-label-name {
  fill: rgba(242, 242, 248, 0.92);
  stroke-width: 4px;
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0;
}

.bh-zoom-label-size {
  fill: rgba(242, 242, 248, 0.5);
  stroke-width: 3px;
  font-size: 12px;
  letter-spacing: 0;
}

.bh-zoom-label.is-selected .bh-zoom-label-name {
  fill: #fff;
}

.bh-zoom-label.is-selected .bh-zoom-label-size {
  fill: var(--acc);
}

.bh-zoom-ref-ring {
  fill: none;
  stroke: rgba(205, 216, 248, 0.2);
  stroke-width: 1;
  stroke-dasharray: 2 7;
}

.bh-zoom-reticle circle {
  fill: rgba(215, 230, 255, 0.45);
}

.bh-zoom-overlay {
  position: absolute;
  z-index: 2;
  inset: 0;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: 12px;
  pointer-events: none;
}

.bh-zoom-visible {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 4px 10px;
  max-width: 76%;
  color: var(--text-dim);
  font-size: 9.5px;
  line-height: 1.45;
}

.bh-zoom-visible-label {
  color: var(--text-soft);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-zoom-visible-item {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: var(--text-soft);
  white-space: nowrap;
}

.bh-zoom-visible-item i {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  box-shadow: 0 0 5px currentColor;
}

.bh-zoom-visible-refs,
.bh-zoom-visible-beyond,
.bh-zoom-visible-empty {
  flex-basis: 100%;
  color: var(--text-dim);
  font-size: 9px;
}

.bh-zoom-visible-beyond {
  color: color-mix(in srgb, var(--accent-warm) 62%, var(--text-dim));
}

.bh-zoom-gesture {
  align-self: flex-end;
  margin: 0;
  color: var(--text-dim);
  font-size: 8px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-zoom-detail {
  --acc: var(--accent);
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 18px;
  border: 1px solid color-mix(in srgb, var(--acc) 24%, var(--line));
  border-radius: var(--radius);
  background:
    radial-gradient(120% 80% at 88% 8%, color-mix(in srgb, var(--acc) 13%, transparent), transparent 58%),
    var(--surface);
}

.bh-zoom-detail-kicker {
  margin: 0 0 8px;
  color: var(--text-dim);
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-zoom-detail h3 {
  margin: 0;
  color: var(--text);
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.08;
}

.bh-zoom-tagline {
  margin: 7px 0 16px;
  color: color-mix(in srgb, var(--acc) 72%, var(--text));
  font-size: 11.5px;
  line-height: 1.55;
}

.bh-zoom-facts {
  display: grid;
  gap: 1px;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--line);
}

.bh-zoom-facts div {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  padding: 7px 9px;
  background: color-mix(in srgb, var(--surface-strong) 70%, transparent);
}

.bh-zoom-facts dt {
  color: var(--text-dim);
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-zoom-facts dd {
  margin: 0;
  color: var(--text-soft);
  font-size: 10.5px;
  line-height: 1.45;
  text-align: right;
}

.bh-zoom-story {
  margin: 15px 0 0;
  color: var(--text-soft);
  font-size: 11.5px;
  line-height: 1.7;
}

.bh-zoom-detail .bh-page-link {
  margin-top: auto;
  align-self: flex-start;
}

.bh-zoom-controls {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) 34px;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
}

.bh-zoom-step {
  appearance: none;
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
}

.bh-zoom-step:hover,
.bh-zoom-step:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 58%, var(--line));
  color: var(--text);
  outline: none;
}

.bh-zoom-range {
  width: 100%;
  accent-color: var(--accent);
  cursor: ew-resize;
}

.bh-zoom-map-wrap {
  margin-top: 14px;
}

.bh-zoom-map-head,
.bh-zoom-map-ends {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  color: var(--text-dim);
  font-size: 8.5px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-zoom-map {
  position: relative;
  height: 40px;
  margin: 7px 0 4px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background:
    linear-gradient(90deg, color-mix(in srgb, var(--accent) 5%, transparent), transparent 34%, color-mix(in srgb, var(--accent-warm) 5%, transparent)),
    var(--surface);
  cursor: ew-resize;
  touch-action: none;
  outline: none;
}

.bh-zoom-map:focus-visible {
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--accent) 40%, transparent);
}

.bh-zoom-map::before {
  content: "";
  position: absolute;
  left: 10px;
  right: 10px;
  top: 50%;
  height: 1px;
  background: rgba(215, 226, 252, 0.12);
}

.bh-zoom-map-window {
  position: absolute;
  z-index: 3;
  top: 5px;
  bottom: 5px;
  left: 0;
  width: 2px;
  border-radius: 999px;
  background: var(--accent-strong);
  box-shadow: 0 0 8px color-mix(in srgb, var(--accent) 75%, transparent);
  transform: translateX(-50%);
}

.bh-zoom-map-window::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 11px;
  height: 11px;
  border: 1px solid var(--accent-strong);
  border-radius: 50%;
  background: var(--page-bg);
  transform: translate(-50%, -50%);
  box-shadow: 0 0 10px color-mix(in srgb, var(--accent) 45%, transparent);
}

.bh-zoom-map-dot {
  position: absolute;
  z-index: 2;
  top: calc(50% + var(--lift, 0px));
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--chip);
  box-shadow: 0 0 6px color-mix(in srgb, var(--chip) 62%, transparent);
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.bh-zoom-map-dot.is-selected {
  width: 10px;
  height: 10px;
  box-shadow: 0 0 0 2px color-mix(in srgb, var(--chip) 24%, transparent), 0 0 12px var(--chip);
}

.bh-zoom-map-tick {
  position: absolute;
  top: 50%;
  padding-top: 18px;
  color: var(--text-dim);
  font-size: 7.5px;
  line-height: 1;
  white-space: nowrap;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.bh-zoom-map-tick::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 3px;
  width: 1px;
  height: 8px;
  background: rgba(215, 226, 252, 0.18);
}

.bh-zoom-quick {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 15px;
}

.bh-zoom-chip {
  appearance: none;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 10px;
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.bh-zoom-chip:hover,
.bh-zoom-chip:focus-visible {
  border-color: color-mix(in srgb, var(--chip) 55%, var(--line));
  color: var(--text);
  outline: none;
}

.bh-zoom-chip.is-selected {
  border-color: color-mix(in srgb, var(--chip) 68%, var(--line));
  background: color-mix(in srgb, var(--chip) 12%, var(--surface));
  color: var(--text);
}

.bh-zoom-chip-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--chip);
  box-shadow: 0 0 6px color-mix(in srgb, var(--chip) 65%, transparent);
}

.bh-zoom-caption {
  margin: 12px 0 0;
  color: var(--text-dim);
  font-size: 10.5px;
  line-height: 1.65;
}

@media (max-width: 980px) {
  .bh-zoom-layout {
    grid-template-columns: 1fr;
  }

  .bh-zoom-detail {
    min-height: auto;
  }
}

@media (max-width: 700px) {
  .bh-zoom-topbar {
    align-items: flex-start;
  }

  .bh-zoom-fov {
    width: 100%;
  }

  .bh-zoom-label-name {
    font-size: 30px;
    stroke-width: 6px;
  }

  .bh-zoom-label-size {
    font-size: 19px;
    stroke-width: 5px;
  }

  .bh-zoom-label:not(.is-selected) {
    display: none !important;
  }

  .bh-zoom-visible {
    max-width: 92%;
    font-size: 8.5px;
  }

  .bh-zoom-map-tick {
    display: none;
  }

  .bh-zoom-facts dd {
    font-size: 10px;
  }
}

.bh-overview {
  display: flex;
  gap: 10px;
  padding: 4px 2px 8px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.bh-overview-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  gap: 7px;
  min-width: 108px;
  padding: 14px 10px 12px;
  border: 1px solid transparent;
  border-radius: 12px;
  background: transparent;
  color: var(--text-dim);
  font: inherit;
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease;
}

.bh-overview-item:hover {
  border-color: var(--line);
  background: var(--surface);
}

.bh-overview-item.is-active {
  border-color: color-mix(in srgb, var(--acc, var(--accent)) 52%, var(--line));
  background: color-mix(in srgb, var(--acc, var(--accent)) 9%, transparent);
}

.bh-overview-dot {
  display: block;
  width: var(--dot);
  height: var(--dot);
  border-radius: 50%;
  background:
    radial-gradient(circle at 50% 50%, #05060a 0 34%, color-mix(in srgb, var(--acc) 88%, #fff) 37%, color-mix(in srgb, var(--acc) 58%, transparent) 54%, transparent 74%);
  box-shadow: 0 0 calc(var(--dot) * 0.5) color-mix(in srgb, var(--acc) 34%, transparent);
  transition: transform 0.18s ease;
}

.bh-overview-item:hover .bh-overview-dot,
.bh-overview-item.is-active .bh-overview-dot {
  transform: scale(1.06);
}

.bh-overview-name {
  color: var(--text);
  font-size: 12px;
  font-weight: 600;
  line-height: 1.25;
  text-align: center;
}

.bh-overview-item:not(.is-active) .bh-overview-name {
  color: var(--text-soft);
  font-weight: 600;
}

.bh-overview-size {
  color: var(--text-dim);
  font-size: 10px;
  line-height: 1.3;
  text-align: center;
}

.bh-overview-mass {
  color: var(--text-dim);
  font-size: 9.5px;
  letter-spacing: 0;
  white-space: nowrap;
}

.bh-overview-readout {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  align-items: baseline;
  margin-top: 4px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.bh-overview-readout .bh-scale-name {
  color: var(--text);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.bh-overview-readout .bh-scale-type {
  color: var(--text-dim);
  font-size: 11px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-overview-readout .bh-scale-stats {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 20px;
  width: 100%;
  margin-top: 3px;
}

.bh-overview-readout .bh-scale-stats span {
  color: var(--text-soft);
  font-size: 12px;
}

.bh-overview-readout .bh-scale-stats b {
  color: var(--text-dim);
  font-weight: 600;
  letter-spacing: 0;
  text-transform: uppercase;
  font-size: 9px;
  margin-right: 6px;
}

.bh-overview-readout .bh-scale-story {
  width: 100%;
  margin: 4px 0 0;
  color: var(--text-soft);
  font-size: 12.5px;
  line-height: 1.7;
}

.bh-truescale {
  margin-top: 30px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.bh-truescale-head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.bh-truescale-head h3 {
  margin: 0;
  color: var(--text);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.bh-truescale-head p {
  margin: 0;
  color: var(--text-soft);
  font-size: 12px;
}

.bh-mode-toggle {
  display: inline-flex;
  gap: 4px;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
}

.bh-mode-btn {
  padding: 6px 12px;
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--text-soft);
  font: inherit;
  font-size: 10.5px;
  cursor: pointer;
  transition: background 0.18s ease, color 0.18s ease, box-shadow 0.18s ease;
}

.bh-mode-btn:hover {
  color: var(--text);
}

.bh-mode-btn.is-active {
  background: var(--surface-strong);
  color: var(--text);
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--accent) 35%, var(--line));
}

.bh-mode-mass-hint {
  display: none;
  margin: 0 0 12px;
  color: var(--text-dim);
  font-size: 11px;
  line-height: 1.6;
}

.bh-truescale.is-mass .bh-mode-mass-hint {
  display: block;
}

.bh-truescale.is-mass .bh-size-atlas,
.bh-truescale.is-mass .bh-size-atlas-note {
  display: none;
}

.bh-truescale:not(.is-mass) .bh-truescale-stage-wrap {
  display: none;
}

.bh-size-atlas {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 14px;
}

.bh-size-panel {
  --acc: var(--accent);
  position: relative;
  appearance: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
  padding: 13px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background:
    radial-gradient(120% 90% at 72% 18%, color-mix(in srgb, var(--acc) 10%, transparent), transparent 62%),
    var(--surface);
  color: var(--text);
  font: inherit;
  text-align: left;
  cursor: pointer;
  overflow: hidden;
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.bh-size-panel::before {
  content: "";
  position: absolute;
  inset: 0 0 auto;
  height: 1px;
  background: linear-gradient(90deg, transparent, color-mix(in srgb, var(--acc) 55%, transparent), transparent);
  opacity: 0.55;
}

.bh-size-panel:hover,
.bh-size-panel:focus-visible {
  border-color: color-mix(in srgb, var(--acc) 48%, var(--line));
  background:
    radial-gradient(120% 90% at 72% 18%, color-mix(in srgb, var(--acc) 15%, transparent), transparent 62%),
    var(--surface-strong);
  transform: translateY(-2px);
  outline: none;
}

.bh-size-panel.is-selected {
  border-color: color-mix(in srgb, var(--acc) 68%, var(--line));
  background:
    radial-gradient(120% 90% at 72% 18%, color-mix(in srgb, var(--acc) 19%, transparent), transparent 62%),
    var(--surface-strong);
  box-shadow: 0 0 0 1px color-mix(in srgb, var(--acc) 20%, transparent), 0 10px 28px rgba(0, 0, 0, 0.22);
}

.bh-size-panel.is-dimmed {
  opacity: 0.34;
}

.bh-size-panel-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px;
}

.bh-size-panel-name {
  color: var(--text);
  font-size: 12.5px;
  font-weight: 600;
  line-height: 1.25;
}

.bh-size-panel-mass {
  flex: 0 0 auto;
  color: var(--text-dim);
  font-size: 9.5px;
  letter-spacing: 0;
  white-space: nowrap;
}

.bh-size-panel-art {
  display: block;
  height: 116px;
}

.bh-size-panel-art svg {
  display: block;
  width: 100%;
  height: 100%;
  overflow: visible;
}

.bh-size-ref-ring {
  fill: none;
  stroke: rgba(255, 255, 255, 0.3);
  stroke-width: 1.2;
  stroke-dasharray: 3 5;
}

.bh-size-horizon-halo {
  fill: color-mix(in srgb, var(--acc) 15%, transparent);
  filter: blur(5px);
}

.bh-size-horizon {
  fill: #03050a;
  stroke: var(--acc);
  stroke-width: 2;
  filter: drop-shadow(0 0 5px color-mix(in srgb, var(--acc) 48%, transparent));
  transition: stroke-width 0.2s ease, filter 0.2s ease;
}

.bh-size-panel:hover .bh-size-horizon,
.bh-size-panel.is-selected .bh-size-horizon {
  stroke-width: 3;
  filter: drop-shadow(0 0 9px color-mix(in srgb, var(--acc) 70%, transparent));
}

.bh-size-panel-foot {
  display: grid;
  gap: 2px;
  margin-top: auto;
  padding-top: 8px;
  border-top: 1px solid var(--line);
  font-size: 9.5px;
  line-height: 1.45;
}

.bh-size-panel-radius {
  color: var(--text-soft);
}

.bh-size-panel-ref {
  color: var(--text-dim);
}

.bh-size-panel-ratio {
  color: color-mix(in srgb, var(--acc) 62%, var(--text));
  font-weight: 600;
  letter-spacing: 0;
}

.bh-size-atlas-note {
  margin: 12px 0 0;
  color: var(--text-dim);
  font-size: 11px;
  line-height: 1.65;
}

.bh-truescale-stage-wrap {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(120% 100% at 50% 42%, #0e1322 0%, #080a12 60%, #05060c 100%);
  overflow: hidden;
}

.bh-truescale-stage {
  display: block;
  width: 100%;
  height: auto;
  max-height: 560px;
}

.bh-ts-ref-ring {
  fill: none;
  stroke: rgba(255, 255, 255, 0.11);
  stroke-width: 1;
  stroke-dasharray: 2 5;
}

.bh-ts-ref-label {
  fill: rgba(242, 242, 248, 0.58);
  font-size: 10.5px;
  letter-spacing: 0;
}

.bh-ts-sun {
  fill: #ffd77a;
  filter: drop-shadow(0 0 4px rgba(255, 215, 122, 0.65));
}

.bh-ts-sun-label {
  fill: rgba(242, 242, 248, 0.55);
  font-size: 10px;
  letter-spacing: 0;
}

.bh-ts-bh {
  fill: none;
  stroke-width: 2;
  transition: opacity 0.18s ease, stroke-width 0.18s ease;
}

.bh-ts-bh.is-selected {
  stroke-width: 3.5;
}

.bh-ts-bh.is-dimmed {
  opacity: 0.2;
}

.bh-truescale-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
  margin-top: 14px;
}

.bh-ts-chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 10.5px;
  cursor: pointer;
  transition: border-color 0.18s ease, color 0.18s ease, background 0.18s ease;
}

.bh-ts-chip:hover {
  border-color: color-mix(in srgb, var(--chip, var(--accent)) 55%, var(--line));
  color: var(--text);
}

.bh-ts-chip.is-selected {
  border-color: color-mix(in srgb, var(--chip, var(--accent)) 62%, var(--line));
  background: color-mix(in srgb, var(--chip, var(--accent)) 10%, var(--surface));
  color: var(--text);
}

.bh-ts-chip-dot {
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--chip, var(--accent));
  box-shadow: 0 0 7px color-mix(in srgb, var(--chip, var(--accent)) 65%, transparent);
}

.bh-truescale-caption {
  margin: 12px 0 0;
  color: var(--text-soft);
  font-size: 12px;
  line-height: 1.7;
}

@media (max-width: 1050px) {
  .bh-size-atlas {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .bh-size-atlas {
    grid-template-columns: 1fr;
  }

  .bh-size-panel-art {
    height: 104px;
  }
}

@media (max-width: 720px) {
  .bh-anatomy-layout {
    display: block;
  }

  .bh-anatomy-detail {
    grid-template-columns: 1fr;
  }

  .bh-anatomy-figure {
    padding: 6px;
  }

  .bh-anatomy-svg .bh-label-title {
    font-size: 11px;
  }

  .bh-anatomy-svg .bh-label-sub {
    font-size: 8.5px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .bh-anatomy-svg .bh-part,
  .bh-anatomy-svg .bh-label,
  .bh-overview-dot,
  .bh-glyph,
  .bh-size-panel,
  .bh-size-horizon,
  .bh-zoom-play,
  .bh-zoom-reset,
  .bh-zoom-chip,
  .bh-zoom-label,
  .bh-zoom-ring,
  .bh-zoom-glow,
  .bh-zoom-fill {
    transition: none;
  }
}

/* ==========================================================================
   Anatomy of a black hole , refined interactive diagram
   ========================================================================== */

.bh-anatomy-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(320px, 0.72fr);
  gap: 14px;
  align-items: center;
}

.bh-anatomy-figure {
  position: relative;
  isolation: isolate;
  margin: 0;
  padding: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(circle at 18% 24%, rgba(171, 207, 255, 0.13) 0 1px, transparent 1.6px),
    radial-gradient(circle at 79% 19%, rgba(171, 207, 255, 0.11) 0 1px, transparent 1.5px),
    radial-gradient(circle at 72% 73%, rgba(171, 207, 255, 0.09) 0 1px, transparent 1.5px),
    radial-gradient(circle at 26% 81%, rgba(171, 207, 255, 0.08) 0 1px, transparent 1.5px),
    radial-gradient(76% 68% at 50% 44%, #121a2c 0%, #090d18 52%, #04060b 100%);
  box-shadow: inset 0 0 70px rgba(0, 0, 0, 0.35);
}

.bh-anatomy-svg {
  position: relative;
  z-index: 1;
  display: block;
  width: 100%;
  height: auto;
}

.bh-anatomy-hotspots {
  position: absolute;
  z-index: 5;
  inset: 0;
  pointer-events: none;
}

.bh-layer {
  cursor: pointer;
  transition: opacity 0.28s ease, filter 0.28s ease;
}

.bh-layer:hover {
  filter: brightness(1.12);
}

.bh-anatomy-svg.is-dimmed .bh-layer {
  opacity: 0.38;
}

.bh-anatomy-svg.is-dimmed .bh-layer.is-active,
.bh-anatomy-svg.is-dimmed .bh-layer.is-preview {
  opacity: 1;
}

.bh-layer.is-active {
  filter: brightness(1.14) saturate(1.08) drop-shadow(0 0 7px var(--part));
}

.bh-layer.is-preview {
  filter: brightness(1.18) saturate(1.08);
}

.bh-photon-dash {
  animation: bhPhotonDrift 24s linear infinite;
}

.bh-hawking-particle {
  fill: var(--part);
  animation: bhHawkingPulse 3.6s ease-in-out infinite;
}

@keyframes bhPhotonDrift {
  to { stroke-dashoffset: -120; }
}

@keyframes bhHawkingPulse {
  0%, 100% { opacity: 0.28; }
  50% { opacity: 0.82; }
}

.bh-hotspot {
  position: absolute;
  left: var(--x);
  top: var(--y);
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: transparent;
  pointer-events: auto;
  cursor: pointer;
  transform: translate(-50%, -50%);
}

.bh-hotspot:focus-visible {
  outline: none;
}

.bh-hotspot[data-part="event-horizon"] { --x: 36%; --y: 50%; }
.bh-hotspot[data-part="photon-sphere"] { --x: 65%; --y: 34%; }
.bh-hotspot[data-part="accretion-disk"] { --x: 22%; --y: 52%; }
.bh-hotspot[data-part="doppler"] { --x: 76%; --y: 48%; }
.bh-hotspot[data-part="jet"] { --x: 50%; --y: 14%; }
.bh-hotspot[data-part="singularity"] { --x: 50%; --y: 50%; }
.bh-hotspot[data-part="hawking"] { --x: 69%; --y: 67%; }

.bh-hotspot-pin {
  display: grid;
  place-items: center;
  width: 26px;
  height: 26px;
  border: 1px solid color-mix(in srgb, var(--chip) 48%, rgba(255, 255, 255, 0.2));
  border-radius: 50%;
  background: color-mix(in srgb, var(--chip) 11%, rgba(5, 8, 15, 0.9));
  color: color-mix(in srgb, var(--chip) 70%, white);
  backdrop-filter: blur(9px);
  box-shadow: 0 0 0 4px rgba(4, 7, 13, 0.26), 0 0 12px color-mix(in srgb, var(--chip) 18%, transparent);
  font-size: 10px;
  font-weight: 600;
  line-height: 1;
  transition: background 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease, color 0.18s ease;
}

.bh-hotspot:hover .bh-hotspot-pin,
.bh-hotspot:focus-visible .bh-hotspot-pin,
.bh-hotspot.is-preview .bh-hotspot-pin,
.bh-hotspot.is-active .bh-hotspot-pin {
  border-color: var(--chip);
  background: color-mix(in srgb, var(--chip) 26%, rgba(5, 8, 15, 0.92));
  color: #fff;
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--chip) 12%, transparent), 0 0 16px color-mix(in srgb, var(--chip) 55%, transparent);
}

.bh-hotspot-label {
  position: absolute;
  z-index: 6;
  padding: 5px 8px;
  border: 1px solid color-mix(in srgb, var(--chip) 44%, var(--line));
  border-left: 2px solid var(--chip);
  border-radius: 7px;
  background: rgba(6, 9, 16, 0.94);
  color: #f2f2f8;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.32);
  font-size: 10px;
  line-height: 1.35;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.18s ease, transform 0.18s ease;
}

.bh-hotspot:hover .bh-hotspot-label,
.bh-hotspot:focus-visible .bh-hotspot-label,
.bh-hotspot.is-preview .bh-hotspot-label,
.bh-hotspot.is-active .bh-hotspot-label {
  opacity: 1;
}

.bh-hotspot[data-side="right"] .bh-hotspot-label {
  left: calc(100% + 1px);
  top: 50%;
  transform: translate(-4px, -50%);
}

.bh-hotspot[data-side="right"]:hover .bh-hotspot-label,
.bh-hotspot[data-side="right"].is-preview .bh-hotspot-label,
.bh-hotspot[data-side="right"].is-active .bh-hotspot-label {
  transform: translate(0, -50%);
}

.bh-hotspot[data-side="left"] .bh-hotspot-label {
  right: calc(100% + 1px);
  top: 50%;
  transform: translate(4px, -50%);
}

.bh-hotspot[data-side="left"]:hover .bh-hotspot-label,
.bh-hotspot[data-side="left"].is-preview .bh-hotspot-label,
.bh-hotspot[data-side="left"].is-active .bh-hotspot-label {
  transform: translate(0, -50%);
}

.bh-hotspot[data-side="top"] .bh-hotspot-label {
  left: 50%;
  bottom: calc(100% + 1px);
  transform: translate(-50%, 4px);
}

.bh-hotspot[data-side="top"]:hover .bh-hotspot-label,
.bh-hotspot[data-side="top"].is-preview .bh-hotspot-label,
.bh-hotspot[data-side="top"].is-active .bh-hotspot-label {
  transform: translate(-50%, 0);
}

.bh-hotspot[data-side="bottom"] .bh-hotspot-label {
  left: 50%;
  top: calc(100% + 1px);
  transform: translate(-50%, -4px);
}

.bh-hotspot[data-side="bottom"]:hover .bh-hotspot-label,
.bh-hotspot[data-side="bottom"].is-preview .bh-hotspot-label,
.bh-hotspot[data-side="bottom"].is-active .bh-hotspot-label {
  transform: translate(-50%, 0);
}

.bh-anatomy-panel {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(100% 70% at 100% 0%, color-mix(in srgb, var(--accent) 7%, transparent), transparent 62%),
    var(--surface);
}

.bh-anatomy-panel-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  color: var(--text-dim);
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-anatomy-copy {
  --chip: var(--accent);
  position: relative;
  margin-top: 10px;
  padding: 16px 16px 17px 18px;
  border: 1px solid color-mix(in srgb, var(--chip) 24%, var(--line));
  border-radius: 12px;
  background:
    radial-gradient(110% 90% at 100% 0%, color-mix(in srgb, var(--chip) 9%, transparent), transparent 58%),
    var(--surface-strong);
}

.bh-anatomy-copy::before {
  content: "";
  position: absolute;
  left: -1px;
  top: 14px;
  bottom: 14px;
  width: 2px;
  border-radius: 2px;
  background: var(--chip);
  box-shadow: 0 0 10px color-mix(in srgb, var(--chip) 62%, transparent);
}

.bh-anatomy-copy.is-changing {
  animation: bhAnatomyCalloutIn 0.28s ease both;
}

@keyframes bhAnatomyCalloutIn {
  from { opacity: 0.55; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

.bh-anatomy-part-tag {
  margin: 0 0 6px;
  color: color-mix(in srgb, var(--chip) 72%, var(--text));
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-anatomy-copy h3 {
  margin: 0 0 8px;
  color: var(--text);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.015em;
  line-height: 1.15;
}

.bh-anatomy-copy #bh-anatomy-part-body {
  margin: 0;
  color: var(--text-soft);
  font-size: 12px;
  line-height: 1.7;
}

.bh-anatomy-chips {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(92px, 1fr));
  gap: 6px;
  margin-top: 12px;
}

.bh-anatomy-chip {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  gap: 7px;
  width: 100%;
  min-height: 44px;
  padding: 7px 8px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 10px;
  text-align: left;
  cursor: pointer;
  transition: border-color 0.18s ease, background 0.18s ease, color 0.18s ease;
}

.bh-anatomy-chip:hover,
.bh-anatomy-chip:focus-visible {
  border-color: color-mix(in srgb, var(--chip, var(--accent)) 48%, var(--line));
  background: var(--surface-strong);
  color: var(--text);
  outline: none;
}

.bh-anatomy-chip.is-active {
  border-color: color-mix(in srgb, var(--chip, var(--accent)) 66%, var(--line));
  background: color-mix(in srgb, var(--chip, var(--accent)) 11%, var(--surface-strong));
  color: var(--text);
}

.bh-anatomy-chip-index {
  flex: 0 0 auto;
  color: var(--text-dim);
  font-size: 8.5px;
  font-variant-numeric: tabular-nums;
  letter-spacing: 0;
}

.bh-anatomy-chip-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--chip, var(--accent));
  box-shadow: 0 0 6px color-mix(in srgb, var(--chip, var(--accent)) 65%, transparent);
}

.bh-anatomy-chip-title {
  min-width: 0;
  font-size: 9.5px;
  line-height: 1.15;
  white-space: normal;
}

.bh-anatomy-panel-foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: auto;
  padding-top: 13px;
}

.bh-anatomy-source {
  margin: 12px 0 0;
  color: var(--text-dim);
  font-size: 9px;
  line-height: 1.55;
}

.bh-anatomy-source a {
  color: var(--text-soft);
  text-decoration-color: color-mix(in srgb, var(--accent) 42%, transparent);
  text-underline-offset: 2px;
}

.bh-anatomy-source a:hover {
  color: var(--text);
}

.bh-anatomy-hint {
  margin: 0;
  color: var(--text-dim);
  font-size: 9.5px;
  line-height: 1.55;
}

.bh-anatomy-overview {
  appearance: none;
  flex: 0 0 auto;
  min-height: 44px;
  padding: 6px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 9.5px;
  cursor: pointer;
}

.bh-anatomy-overview:hover,
.bh-anatomy-overview:focus-visible,
.bh-anatomy-overview.is-active {
  border-color: color-mix(in srgb, var(--accent) 48%, var(--line));
  background: var(--surface-strong);
  color: var(--text);
  outline: none;
}

@media (max-width: 980px) {
  .bh-anatomy-layout {
    display: grid;
    grid-template-columns: 1fr;
  }

  .bh-anatomy-panel {
    min-height: auto;
  }
}

@media (max-width: 700px) {
  .bh-anatomy-figure {
    padding: 0;
  }

  .bh-hotspot-label {
    display: none;
  }

  .bh-hotspot-pin {
    width: 24px;
    height: 24px;
    font-size: 9px;
  }

  .bh-anatomy-panel {
    padding: 12px;
  }

  .bh-anatomy-copy h3 {
    font-size: 19px;
  }

  .bh-anatomy-chip {
    min-height: 44px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .bh-layer,
  .bh-hotspot-pin,
  .bh-hotspot-label,
  .bh-anatomy-chip,
  .bh-anatomy-overview {
    transition: none;
  }

  .bh-photon-dash,
  .bh-hawking-particle {
    animation: none;
  }

  .bh-anatomy-copy.is-changing {
    animation: none;
  }
}

/* ==========================================================================
   Anatomy , rotatable 2.5D scene
   ========================================================================== */

.bh-anatomy-figure {
  padding: 0;
}

.bh-anatomy-stage {
  position: relative;
  width: 100%;
  aspect-ratio: 1000 / 660;
  overflow: hidden;
  perspective: 1100px;
  perspective-origin: 50% 47%;
  touch-action: none;
  cursor: grab;
  user-select: none;
  outline: none;
  background:
    radial-gradient(circle at 18% 25%, rgba(171, 207, 255, 0.14) 0 1px, transparent 1.6px),
    radial-gradient(circle at 79% 18%, rgba(171, 207, 255, 0.11) 0 1px, transparent 1.5px),
    radial-gradient(circle at 72% 73%, rgba(171, 207, 255, 0.09) 0 1px, transparent 1.5px),
    radial-gradient(circle at 26% 81%, rgba(171, 207, 255, 0.08) 0 1px, transparent 1.5px),
    radial-gradient(76% 68% at 50% 44%, #111827 0%, #0b101a 54%, #070a12 100%);
}

.bh-anatomy-stage::after {
  content: "";
  position: absolute;
  z-index: 3;
  inset: 0;
  background: radial-gradient(65% 62% at 50% 50%, transparent 38%, rgba(3, 5, 10, 0.34) 100%);
  pointer-events: none;
}

.bh-anatomy-stage.is-dragging,
.bh-anatomy-stage.is-dragging * {
  cursor: grabbing;
}

.bh-anatomy-stage:focus-visible {
  box-shadow: inset 0 0 0 2px color-mix(in srgb, var(--accent) 48%, transparent);
}

.bh-anatomy-scene {
  position: absolute;
  inset: 0;
  z-index: 1;
  transform-style: preserve-3d;
  pointer-events: none;
}

.bh-anatomy-rotor {
  position: absolute;
  inset: 0;
  transform: rotateX(var(--pitch, 8deg)) rotateY(var(--yaw, -12deg));
  transform-style: preserve-3d;
  transform-origin: 50% 50%;
  pointer-events: none;
  will-change: transform;
}

.bh-anatomy-static {
  position: absolute;
  z-index: 2;
  inset: 0;
  pointer-events: none;
}

.bh-anatomy-jets,
.bh-anatomy-disk,
.bh-anatomy-doppler {
  position: absolute;
  left: 50%;
  top: 50%;
  transform-style: preserve-3d;
}

.bh-anatomy-jets {
  width: 14%;
  height: 74%;
  transform: translate(-50%, -50%) translateZ(-28px);
  pointer-events: auto;
  cursor: pointer;
}

.bh-anatomy-disk,
.bh-anatomy-doppler {
  width: 74%;
  aspect-ratio: 1;
  transform: translate(-50%, -50%) rotateX(66deg) translateZ(-4px);
}

.bh-anatomy-disk {
  pointer-events: auto;
  cursor: pointer;
}

.bh-anatomy-doppler {
  pointer-events: none;
}

.bh-anatomy-doppler .bh-doppler-arc {
  pointer-events: none;
}

.bh-m87-vector {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: contain;
  filter: saturate(1.08) brightness(1.04);
  pointer-events: none;
}

.bh-doppler-node {
  position: absolute;
  left: 2%;
  top: 55%;
  width: 24%;
  height: 24%;
  border-radius: 50%;
  background: radial-gradient(circle,
    rgba(255, 248, 226, 0.24) 0%,
    rgba(255, 186, 99, 0.11) 42%,
    transparent 72%);
  filter: blur(4px);
  opacity: 0.52;
  pointer-events: auto;
  cursor: pointer;
  transition: opacity 0.25s ease, filter 0.25s ease;
}

.bh-anatomy-doppler .bh-anchor {
  left: 14%;
  top: 67%;
}

.bh-doppler-node.is-active {
  opacity: 1;
  filter: blur(2px) brightness(1.24) drop-shadow(0 0 11px rgba(255, 228, 169, 0.6));
}

.bh-doppler-node.is-preview {
  opacity: 1;
  filter: blur(2px) brightness(1.3);
}

.bh-jet {
  position: absolute;
  left: 50%;
  width: 100%;
  transform: translateX(-50%);
  filter: blur(0.5px) drop-shadow(0 0 8px rgba(123, 193, 255, 0.2));
  opacity: 0.42;
}

.bh-jet-top {
  top: 0;
  height: 47%;
  background: linear-gradient(to top, rgba(117, 191, 255, 0) 0%, rgba(117, 191, 255, 0.3) 38%, rgba(217, 241, 255, 0.82) 100%);
  clip-path: polygon(43% 100%, 57% 100%, 91% 0, 9% 0);
}

.bh-jet-bottom {
  bottom: 0;
  height: 47%;
  background: linear-gradient(to bottom, rgba(117, 191, 255, 0) 0%, rgba(117, 191, 255, 0.3) 38%, rgba(217, 241, 255, 0.82) 100%);
  clip-path: polygon(43% 0, 57% 0, 91% 100%, 9% 100%);
}

.bh-jet::after {
  content: "";
  position: absolute;
  left: 50%;
  width: 2px;
  height: 82%;
  background: linear-gradient(to top, transparent, rgba(230, 247, 255, 0.92), transparent);
  transform: translateX(-50%);
  filter: blur(1.2px);
}

.bh-jet-bottom::after {
  bottom: 0;
  background: linear-gradient(to bottom, transparent, rgba(230, 247, 255, 0.92), transparent);
}

.bh-jet-top::after {
  top: 0;
}

.bh-jet-spark {
  position: absolute;
  left: 50%;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: #d9f1ff;
  box-shadow: 0 0 8px rgba(194, 232, 255, 0.8);
  opacity: 0.55;
  transform: translateX(-50%);
}

.bh-jet-spark-top { top: 22%; }
.bh-jet-spark-bottom { bottom: 22%; }

.bh-disk-haze {
  position: absolute;
  inset: -7%;
  border-radius: 50%;
  background: radial-gradient(circle, transparent 42%, rgba(255, 154, 82, 0.16) 58%, rgba(255, 154, 82, 0.03) 72%, transparent 78%);
  filter: blur(16px);
}

.bh-disk-ring {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: conic-gradient(from 18deg,
    #40151c 0%,
    #a84332 11%,
    #ffb167 29%,
    #ffe4bd 45%,
    #f18b4d 60%,
    #7b2a24 79%,
    #351219 100%);
  -webkit-mask: radial-gradient(farthest-side, transparent 0 78%, #000 79% 98%, transparent 99%);
  mask: radial-gradient(farthest-side, transparent 0 78%, #000 79% 98%, transparent 99%);
}

.bh-disk-ring-outer {
  inset: -4%;
  opacity: 0.22;
  filter: blur(9px);
  -webkit-mask: radial-gradient(farthest-side, transparent 0 69%, #000 70% 100%);
  mask: radial-gradient(farthest-side, transparent 0 69%, #000 70% 100%);
}

.bh-disk-ring-main {
  filter: drop-shadow(0 0 12px rgba(255, 147, 78, 0.28));
}

.bh-disk-ring-inner {
  inset: 12%;
  opacity: 0.52;
  filter: blur(0.8px);
  -webkit-mask: radial-gradient(farthest-side, transparent 0 87%, #000 88% 100%);
  mask: radial-gradient(farthest-side, transparent 0 87%, #000 88% 100%);
}

.bh-doppler-arc {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: conic-gradient(from -67deg,
    transparent 0 39%,
    rgba(255, 249, 228, 0.9) 48%,
    transparent 59% 100%);
  -webkit-mask: radial-gradient(farthest-side, transparent 0 79%, #000 80% 96%, transparent 97%);
  mask: radial-gradient(farthest-side, transparent 0 79%, #000 80% 96%, transparent 97%);
  filter: drop-shadow(0 0 10px rgba(255, 245, 219, 0.44));
  opacity: 0.9;
}

.bh-anatomy-photon,
.bh-anatomy-horizon {
  position: absolute;
  left: 50%;
  top: 50%;
  aspect-ratio: 1;
  transform: translate(-50%, -50%);
  pointer-events: none;
}

.bh-anatomy-photon {
  width: 22%;
}

.bh-anatomy-horizon {
  width: 16%;
  pointer-events: auto;
  cursor: pointer;
}

.bh-photon-ring,
.bh-photon-dash {
  position: absolute;
  inset: 0;
  border-radius: 50%;
}

.bh-photon-ring {
  background: conic-gradient(from 8deg,
    rgba(255, 227, 186, 0.25) 0%,
    rgba(255, 246, 218, 0.9) 16%,
    rgba(255, 205, 139, 0.22) 34%,
    rgba(255, 245, 219, 0.78) 55%,
    rgba(255, 220, 160, 0.2) 73%,
    rgba(255, 244, 213, 0.88) 89%,
    rgba(255, 227, 186, 0.25) 100%);
  -webkit-mask: radial-gradient(farthest-side, transparent 0 93%, #000 94% 100%);
  mask: radial-gradient(farthest-side, transparent 0 93%, #000 94% 100%);
  filter: drop-shadow(0 0 9px rgba(255, 224, 170, 0.36));
}

.bh-photon-dash {
  inset: -3%;
  background: repeating-conic-gradient(from 0deg,
    rgba(255, 244, 217, 0.82) 0deg 1deg,
    transparent 1deg 11deg);
  -webkit-mask: radial-gradient(farthest-side, transparent 0 94%, #000 95% 100%);
  mask: radial-gradient(farthest-side, transparent 0 94%, #000 95% 100%);
  opacity: 0.72;
  animation: bhPhotonSpin 28s linear infinite;
}

.bh-horizon-disc {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: radial-gradient(circle at 39% 34%, #111a2e 0%, #050912 31%, #010205 68%, #000 100%);
  box-shadow:
    0 0 0 1px rgba(155, 199, 255, 0.32),
    0 0 22px rgba(110, 173, 255, 0.2),
    inset 0 0 34px rgba(0, 0, 0, 0.96);
}

.bh-horizon-disc::after {
  content: "";
  position: absolute;
  inset: -2.5%;
  border: 1px solid rgba(170, 208, 255, 0.25);
  border-radius: 50%;
  box-shadow: 0 0 14px rgba(123, 183, 255, 0.18);
}

.bh-anatomy-singularity {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.bh-singularity-core {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: radial-gradient(circle, #fff 0 18%, #ffe9c4 33%, rgba(255, 233, 196, 0.1) 72%);
  box-shadow: 0 0 18px rgba(255, 249, 229, 0.94), 0 0 44px rgba(255, 220, 164, 0.28);
  transform: translate(-50%, -50%);
  animation: bhSingularityPulse 3.4s ease-in-out infinite;
}

.bh-singularity-core::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 46px;
  height: 46px;
  border: 1px dashed rgba(255, 233, 196, 0.25);
  border-radius: 50%;
  transform: translate(-50%, -50%);
}

.bh-anatomy-hawking {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.bh-anatomy-hawking i {
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--part);
  box-shadow: 0 0 9px rgba(185, 198, 255, 0.84);
  transform: translate(-50%, -50%);
  animation: bhHawkingFloat 4.6s ease-in-out infinite;
  animation-delay: var(--delay);
}

.bh-anatomy-jets .bh-anchor { left: 50%; top: 2%; }
.bh-anatomy-disk .bh-anchor { left: 1%; top: 50%; }
.bh-anatomy-doppler .bh-anchor { left: 99%; top: 50%; }
.bh-anatomy-photon .bh-anchor { left: 84%; top: 16%; }
.bh-anatomy-horizon .bh-anchor { left: 0; top: 50%; }
.bh-anatomy-singularity .bh-anchor { left: 50%; top: 50%; }
.bh-anatomy-hawking .bh-anchor { left: 70%; top: 70%; }

.bh-anchor {
  position: absolute;
  width: 2px;
  height: 2px;
  pointer-events: none;
  transform: translate(-50%, -50%);
}

.bh-anatomy-links {
  position: absolute;
  z-index: 4;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: visible;
  pointer-events: none;
}

.bh-anatomy-link-line {
  fill: none;
  stroke-width: 1;
  stroke-dasharray: 2 4;
  opacity: 0.5;
}

.bh-anatomy-stage.is-dimmed .bh-part-layer {
  opacity: 0.65;
}

.bh-anatomy-stage.is-dimmed .bh-part-layer.is-active,
.bh-anatomy-stage.is-dimmed .bh-part-layer.is-preview {
  opacity: 1;
}

.bh-part-layer {
  transition: opacity 0.25s ease, filter 0.25s ease;
}

.bh-part-layer.is-active {
  filter: brightness(1.14) saturate(1.08) drop-shadow(0 0 8px var(--part));
}

.bh-part-layer.is-preview {
  filter: brightness(1.2) saturate(1.08);
}

.bh-anatomy-hotspots {
  z-index: 7;
}

.bh-anatomy-callout {
  --callout-color: var(--accent);
  position: absolute;
  z-index: 8;
  width: 190px;
  padding: 9px 10px;
  border: 1px solid color-mix(in srgb, var(--callout-color) 38%, rgba(255, 255, 255, 0.12));
  border-left: 2px solid var(--callout-color);
  border-radius: 9px;
  background: rgba(6, 9, 16, 0.95);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.36);
  color: #f2f2f8;
  pointer-events: none;
  opacity: 0;
  visibility: hidden;
  transform: translateY(4px);
  transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s ease;
}

.bh-anatomy-callout.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.bh-anatomy-callout-tag {
  display: block;
  margin-bottom: 3px;
  color: color-mix(in srgb, var(--callout-color) 76%, white);
  font-size: 7.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-anatomy-callout strong {
  display: block;
  font-size: 11.5px;
  font-weight: 600;
  line-height: 1.25;
}

.bh-anatomy-callout-summary {
  display: block;
  margin-top: 4px;
  color: rgba(242, 242, 248, 0.64);
  font-size: 9px;
  line-height: 1.45;
}

.bh-anatomy-rotate-ui {
  position: absolute;
  z-index: 9;
  left: 12px;
  right: 12px;
  bottom: 11px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  pointer-events: none;
}

.bh-anatomy-rotate-hint {
  color: rgba(240, 238, 232, 0.5);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-anatomy-rotate-reset {
  appearance: none;
  min-height: 44px;
  padding: 5px 9px;
  border: 1px solid rgba(224, 234, 255, 0.18);
  border-radius: 999px;
  background: rgba(6, 9, 16, 0.62);
  color: rgba(240, 238, 232, 0.72);
  font: inherit;
  font-size: 9px;
  cursor: pointer;
  pointer-events: auto;
  backdrop-filter: blur(8px);
}

.bh-anatomy-rotate-reset:hover,
.bh-anatomy-rotate-reset:focus-visible {
  border-color: color-mix(in srgb, var(--accent) 62%, rgba(224, 234, 255, 0.18));
  color: #f0eee8;
  outline: none;
}

@keyframes bhPhotonSpin {
  to { transform: rotate(360deg); }
}

@keyframes bhSingularityPulse {
  0%, 100% { opacity: 0.78; transform: translate(-50%, -50%) scale(0.9); }
  50% { opacity: 1; transform: translate(-50%, -50%) scale(1.08); }
}

@keyframes bhHawkingFloat {
  0%, 100% { opacity: 0.24; transform: translate(-50%, -50%) translateY(0); }
  50% { opacity: 0.84; transform: translate(-50%, -50%) translateY(-4px); }
}

@media (max-width: 700px) {
  .bh-anatomy-callout {
    display: none;
  }

  .bh-anatomy-rotate-ui {
    left: 8px;
    right: 8px;
    bottom: 7px;
  }

  .bh-anatomy-rotate-reset {
    min-height: 44px;
    font-size: 8.5px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .bh-anatomy-rotor,
  .bh-anatomy-callout,
  .bh-part-layer,
  .bh-anatomy-rotate-reset {
    transition: none;
  }

  .bh-photon-dash,
  .bh-singularity-core,
  .bh-anatomy-hawking i {
    animation: none;
  }
}

/* ==========================================================================
   Anatomy , image-derived vector relief
   ========================================================================== */

.bh-picture-layer {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 92%;
  aspect-ratio: 1000 / 620;
  transform: translate(-50%, -50%);
  transform-style: preserve-3d;
  pointer-events: none;
}

.bh-picture-layer img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  pointer-events: none;
}

.bh-picture-halo {
  transform: translate(-50%, -50%) scale(1.055) translateZ(-32px);
  opacity: 0.3;
  filter: blur(18px) saturate(1.3) brightness(0.86);
}

.bh-picture-main {
  transform: translate(-50%, -50%) translateZ(0);
  pointer-events: auto;
  cursor: pointer;
}

.bh-picture-main img {
  filter: saturate(1.04) brightness(0.98);
}

.bh-picture-main.is-active {
  filter: brightness(1.03) saturate(1.04);
}

.bh-picture-event {
  transform: translate(-50%, -50%) translateZ(8px);
}

.bh-picture-photon {
  transform: translate(-50%, -50%) translateZ(6px);
}

.bh-picture-lensed {
  transform: translate(-50%, -50%) translateZ(5px);
}

.bh-picture-doppler {
  transform: translate(-50%, -50%) translateZ(10px);
}

.bh-picture-turbulence {
  transform: translate(-50%, -50%) translateZ(7px);
}

.bh-picture-jet {
  transform: translate(-50%, -50%) translateZ(4px);
}

.bh-picture-singularity {
  transform: translate(-50%, -50%) translateZ(9px);
}

.bh-picture-hawking {
  transform: translate(-50%, -50%) translateZ(10px);
}

.bh-picture-main .bh-anchor { left: 15%; top: 52%; }
.bh-picture-event .bh-anchor { left: 32%; top: 52%; }
.bh-picture-photon .bh-anchor { left: 39%; top: 36%; }
.bh-picture-lensed .bh-anchor { left: 50%; top: 28%; }
.bh-picture-doppler .bh-anchor { left: 23%; top: 66%; }
.bh-picture-turbulence .bh-anchor { left: 74%; top: 57%; }
.bh-picture-jet .bh-anchor { left: 50%; top: 13%; }
.bh-picture-singularity .bh-anchor { left: 50%; top: 52%; }
.bh-picture-hawking .bh-anchor { left: 65%; top: 39%; }

.bh-shadow-organic {
  position: absolute;
  left: 50%;
  top: 52%;
  width: 37%;
  height: 36%;
  border: 1px solid rgba(136, 191, 255, 0.14);
  border-radius: 48% 52% 46% 54% / 54% 45% 55% 46%;
  background: radial-gradient(ellipse, transparent 55%, rgba(104, 157, 229, 0.035) 72%, transparent 90%);
  box-shadow: inset 0 0 20px rgba(92, 141, 209, 0.07);
  transform: translate(-50%, -50%) rotate(-3deg);
  pointer-events: auto;
  cursor: pointer;
}

.bh-photon-arc {
  position: absolute;
  left: 27%;
  top: 30%;
  width: 25%;
  height: 23%;
  border-top: 1.4px solid rgba(255, 235, 195, 0.48);
  border-radius: 50% 50% 0 0;
  filter: drop-shadow(0 0 5px rgba(255, 218, 158, 0.32));
  transform: rotate(-11deg);
  pointer-events: auto;
  cursor: pointer;
}

.bh-lensed-arc {
  position: absolute;
  left: 19%;
  top: 20%;
  width: 63%;
  height: 27%;
  border-top: 1px solid rgba(204, 227, 255, 0.36);
  border-radius: 50% 50% 0 0;
  filter: drop-shadow(0 0 6px rgba(160, 204, 255, 0.2));
  transform: rotate(-3deg);
  pointer-events: auto;
  cursor: pointer;
}

.bh-doppler-knot {
  position: absolute;
  left: 12%;
  top: 55%;
  width: 23%;
  height: 22%;
  border-radius: 50%;
  background: radial-gradient(ellipse,
    rgba(255, 244, 217, 0.34) 0%,
    rgba(255, 198, 116, 0.16) 38%,
    transparent 72%);
  filter: blur(7px);
  transform: rotate(-8deg);
  pointer-events: auto;
  cursor: pointer;
}

.bh-turbulence-knot {
  position: absolute;
  left: 63%;
  top: 46%;
  width: 22%;
  height: 22%;
  border-radius: 50%;
  background:
    radial-gradient(ellipse at 35% 40%, rgba(255, 231, 190, 0.22), transparent 34%),
    radial-gradient(ellipse at 68% 58%, rgba(255, 147, 79, 0.14), transparent 46%);
  filter: blur(6px);
  transform: rotate(8deg);
  pointer-events: auto;
  cursor: pointer;
}

.bh-key-jet {
  position: absolute;
  left: 50%;
  width: 8%;
  opacity: 0.2;
  filter: blur(1.4px) drop-shadow(0 0 7px rgba(141, 204, 255, 0.26));
  transform: translateX(-50%);
  pointer-events: none;
  transition: opacity 0.25s ease, filter 0.25s ease;
}

.bh-key-jet-top {
  top: 5%;
  height: 41%;
  background: linear-gradient(to top, rgba(151, 212, 255, 0.68), transparent 92%);
  clip-path: polygon(36% 100%, 64% 100%, 100% 0, 0 0);
}

.bh-key-jet-bottom {
  bottom: 5%;
  height: 41%;
  background: linear-gradient(to bottom, rgba(151, 212, 255, 0.68), transparent 92%);
  clip-path: polygon(36% 0, 64% 0, 100% 100%, 0 100%);
}

.bh-picture-jet.is-active .bh-key-jet,
.bh-picture-jet.is-preview .bh-key-jet {
  opacity: 0.62;
  filter: blur(1.2px) drop-shadow(0 0 12px rgba(141, 204, 255, 0.52));
}

.bh-key-singularity {
  position: absolute;
  left: 50%;
  top: 52%;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #fff9ea;
  box-shadow: 0 0 10px rgba(255, 245, 220, 0.8), 0 0 24px rgba(255, 219, 161, 0.28);
  opacity: 0.34;
  transform: translate(-50%, -50%);
  pointer-events: none;
  animation: bhKeyPulse 3.4s ease-in-out infinite;
}

.bh-picture-singularity.is-active .bh-key-singularity,
.bh-picture-singularity.is-preview .bh-key-singularity {
  opacity: 1;
  animation: none;
  box-shadow: 0 0 13px rgba(255, 249, 231, 0.95), 0 0 30px rgba(255, 209, 143, 0.44);
}

.bh-key-particle {
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: #b9c6ff;
  box-shadow: 0 0 7px rgba(185, 198, 255, 0.7);
  opacity: 0.18;
  transform: translate(-50%, -50%);
  animation: bhKeyParticle 4.6s ease-in-out infinite;
  animation-delay: var(--delay);
  pointer-events: none;
}

.bh-picture-hawking.is-active .bh-key-particle,
.bh-picture-hawking.is-preview .bh-key-particle {
  opacity: 0.82;
  animation: none;
}

.bh-anatomy-stage.is-dimmed .bh-picture-event {
  opacity: 1;
}

.bh-anatomy-stage.is-dimmed .bh-picture-main {
  opacity: 0.96;
}

.bh-picture-event.is-active .bh-shadow-organic {
  border-color: rgba(146, 195, 255, 0.38);
  box-shadow:
    inset 0 0 20px rgba(92, 141, 209, 0.12),
    0 0 17px rgba(126, 181, 255, 0.14);
}

.bh-picture-photon.is-active .bh-photon-arc,
.bh-picture-photon.is-preview .bh-photon-arc {
  border-top-color: rgba(255, 247, 220, 1);
  filter: drop-shadow(0 0 9px rgba(255, 222, 168, 0.74));
}

.bh-picture-lensed.is-active .bh-lensed-arc,
.bh-picture-lensed.is-preview .bh-lensed-arc {
  border-top-color: rgba(229, 242, 255, 0.95);
  filter: drop-shadow(0 0 9px rgba(166, 207, 255, 0.62));
}

.bh-picture-doppler.is-active .bh-doppler-knot,
.bh-picture-doppler.is-preview .bh-doppler-knot {
  filter: blur(3px) brightness(1.35);
}

.bh-picture-turbulence.is-active .bh-turbulence-knot,
.bh-picture-turbulence.is-preview .bh-turbulence-knot {
  filter: blur(3px) brightness(1.4) saturate(1.2);
}

@keyframes bhKeyPulse {
  0%, 100% { opacity: 0.28; transform: translate(-50%, -50%) scale(0.88); }
  50% { opacity: 0.78; transform: translate(-50%, -50%) scale(1.08); }
}

@keyframes bhKeyParticle {
  0%, 100% { opacity: 0.12; transform: translate(-50%, -50%) translateY(0); }
  50% { opacity: 0.68; transform: translate(-50%, -50%) translateY(-3px); }
}

@media (prefers-reduced-motion: reduce) {
  .bh-key-singularity,
  .bh-key-particle {
    animation: none;
  }
}

@media (max-width: 980px) {
  .bh-anatomy-layout {
    align-items: start;
  }
}

/* ==========================================================================
   Annotated black hole in motion
   ========================================================================== */

.bh-motion {
  margin-top: 10px;
}

.bh-motion-figure {
  width: min(100%, 820px);
  margin: 0 auto;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #05070d;
  box-shadow: var(--shadow-soft);
}

.bh-motion-stage {
  position: relative;
  width: 100%;
  aspect-ratio: 985 / 568;
  overflow: hidden;
  background: #05070d;
}

.bh-motion-gif {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center;
}

.bh-motion-highlights {
  position: absolute;
  z-index: 2;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.bh-motion-highlight {
  opacity: 0;
  transition: opacity 0.18s ease;
}

.bh-motion-highlight.is-active {
  opacity: 1;
}

.bh-motion-highlight .bh-disk {
  fill: color-mix(in srgb, var(--part-color) 12%, transparent);
  stroke: color-mix(in srgb, var(--part-color) 82%, white);
  stroke-width: 1.8;
  stroke-linejoin: round;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 0 3px color-mix(in srgb, var(--part-color) 65%, transparent))
          drop-shadow(0 0 10px color-mix(in srgb, var(--part-color) 30%, transparent));
}

.bh-motion-highlight .bh-horizon {
  fill: color-mix(in srgb, var(--part-color) 10%, transparent);
  stroke: var(--part-color);
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 0 6px color-mix(in srgb, var(--part-color) 65%, transparent));
}

.bh-motion-highlight .bh-ring {
  fill: none;
  stroke: color-mix(in srgb, var(--part-color) 90%, white);
  stroke-width: 1.6;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 0 5px color-mix(in srgb, var(--part-color) 55%, transparent));
}

.bh-motion-highlight .bh-doppler {
  fill: none;
  stroke: color-mix(in srgb, var(--part-color) 78%, transparent);
  stroke-width: 3.2;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 0 5px color-mix(in srgb, var(--part-color) 55%, transparent));
}

.bh-motion-highlight .bh-arc {
  fill: none;
  stroke: var(--part-color);
  stroke-width: 2.2;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
  filter: drop-shadow(0 0 5px color-mix(in srgb, var(--part-color) 65%, transparent));
}

.bh-motion-leader {
  position: absolute;
  z-index: 2;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.bh-motion-leader line {
  stroke: var(--leader-color, var(--accent));
  stroke-width: 1;
  stroke-dasharray: 4 5;
  vector-effect: non-scaling-stroke;
  opacity: 0.8;
}

.bh-motion-highlight-jet {
  mix-blend-mode: screen;
}

.bh-motion-highlight-jet .bh-jet-beam {
  opacity: 0.6;
}

.bh-motion-highlight-jet .bh-jet-spine {
  stroke: #ffffff;
  stroke-width: 1.4;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
  opacity: 0.75;
  filter: drop-shadow(0 0 5px rgba(207, 230, 255, 0.95));
}

.bh-motion-highlight-jet .bh-jet-particles {
  filter: drop-shadow(0 0 4px rgba(207, 230, 255, 0.9));
}

.bh-motion-highlight-jet.is-active .bh-jet-beam {
  animation: bhJetPulse 1.05s ease-in-out infinite;
}

.bh-motion-highlight-jet.is-active .bh-jet-spine {
  animation: bhJetSpine 0.6s ease-in-out infinite;
}

.bh-motion-highlight-jet .bh-jet-flare {
  fill: #eaf7ff;
  opacity: 0;
  transform-box: fill-box;
  transform-origin: center;
  filter: drop-shadow(0 0 6px rgba(207, 230, 255, 0.9));
}

.bh-motion-highlight-jet .bh-jet-burst {
  fill: none;
  stroke: #ffffff;
  stroke-width: 1.5;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
  opacity: 0;
  filter: drop-shadow(0 0 4px rgba(207, 230, 255, 0.95));
}

.bh-motion-highlight-jet.is-active .bh-jet-flare {
  opacity: 1;
  animation: bhJetFlare 1.35s ease-in-out infinite;
}

.bh-motion-highlight-jet.is-active .bh-jet-flare-2,
.bh-motion-highlight-jet.is-active .bh-jet-flare-5 {
  animation-delay: 0.35s;
}

.bh-motion-highlight-jet.is-active .bh-jet-flare-3,
.bh-motion-highlight-jet.is-active .bh-jet-flare-4 {
  animation-delay: 0.7s;
}

.bh-motion-highlight-jet.is-active .bh-jet-burst {
  opacity: 0.9;
  animation: bhJetBurst 0.9s ease-in-out infinite;
}

@keyframes bhJetPulse {
  0%, 100% { opacity: 0.55; }
  50% { opacity: 1; }
}

@keyframes bhJetSpine {
  0%, 100% { opacity: 0.55; }
  50% { opacity: 1; }
}

@keyframes bhJetFlare {
  0%, 100% { opacity: 0.15; transform: scale(0.65); }
  45% { opacity: 0.95; transform: scale(1.3); }
}

@keyframes bhJetBurst {
  0%, 100% { opacity: 0.15; }
  45% { opacity: 1; }
}

.bh-motion-focus {
  position: absolute;
  z-index: 3;
  width: 44px;
  height: 44px;
  border: 1px solid var(--focus-color, var(--accent));
  border-radius: 50%;
  box-shadow: 0 0 14px color-mix(in srgb, var(--focus-color, var(--accent)) 40%, transparent);
  opacity: 0;
  transform: translate(-50%, -50%) scale(0.85);
  transition: opacity 0.18s ease, transform 0.18s ease;
  pointer-events: none;
}

.bh-motion-focus.is-visible {
  opacity: 1;
  transform: translate(-50%, -50%) scale(1);
}

.bh-motion-pins {
  position: absolute;
  z-index: 4;
  inset: 0;
  pointer-events: none;
}

.bh-motion-pin {
  position: absolute;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: #f2f2f8;
  font: inherit;
  cursor: pointer;
  transform: translate(-50%, -50%);
  pointer-events: auto;
}

.bh-motion-pin-dot {
  display: grid;
  place-items: center;
  width: 20px;
  height: 20px;
  border: 1px solid color-mix(in srgb, var(--chip) 58%, rgba(255, 255, 255, 0.25));
  border-radius: 50%;
  background: color-mix(in srgb, var(--chip) 16%, rgba(6, 9, 16, 0.68));
  color: #f2f2f8;
  box-shadow: 0 0 0 4px rgba(5, 8, 14, 0.3), 0 0 8px color-mix(in srgb, var(--chip) 35%, transparent);
  font-size: 8px;
  font-weight: 600;
  line-height: 1;
  transition: background 0.18s ease, border-color 0.18s ease, box-shadow 0.18s ease;
}

.bh-motion-pin:hover .bh-motion-pin-dot,
.bh-motion-pin:focus-visible .bh-motion-pin-dot,
.bh-motion-pin.is-active .bh-motion-pin-dot,
.bh-motion-pin.is-preview .bh-motion-pin-dot {
  border-color: var(--chip);
  background: color-mix(in srgb, var(--chip) 32%, rgba(6, 9, 16, 0.78));
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--chip) 12%, transparent),
              0 0 13px color-mix(in srgb, var(--chip) 62%, transparent);
}

.bh-motion-pin:focus-visible {
  outline: none;
}

.bh-motion-label {
  --chip: var(--accent);
  position: absolute;
  z-index: 5;
  left: 68%;
  display: grid;
  gap: 2px;
  width: min(29%, 255px);
  min-height: 44px;
  padding: 7px 9px;
  border: 1px solid color-mix(in srgb, var(--chip) 32%, rgba(255, 255, 255, 0.13));
  border-radius: 8px;
  background: rgba(7, 10, 17, 0.86);
  color: #f2f2f8;
  font: inherit;
  text-align: left;
  cursor: pointer;
  transform: translateY(-50%);
  backdrop-filter: blur(7px);
  transition: border-color 0.18s ease, background 0.18s ease, box-shadow 0.18s ease;
}

.bh-motion-label:hover,
.bh-motion-label:focus-visible,
.bh-motion-label.is-active,
.bh-motion-label.is-preview {
  border-color: color-mix(in srgb, var(--chip) 78%, rgba(255, 255, 255, 0.2));
  background: rgba(10, 14, 24, 0.96);
  box-shadow: 0 7px 22px rgba(0, 0, 0, 0.28);
  outline: none;
}

.bh-motion-label-title {
  display: block;
  color: #f5f2ec;
  font-size: 10.5px;
  font-weight: 600;
  line-height: 1.25;
}

.bh-motion-label-title::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 6px;
  margin-right: 6px;
  border-radius: 50%;
  background: var(--chip);
  box-shadow: 0 0 6px color-mix(in srgb, var(--chip) 60%, transparent);
  vertical-align: 1px;
}

.bh-motion-label-tagline {
  display: block;
  color: rgba(240, 238, 232, 0.52);
  font-size: 8.5px;
  line-height: 1.25;
}

.bh-motion-label:hover .bh-motion-label-tagline,
.bh-motion-label.is-active .bh-motion-label-tagline,
.bh-motion-label.is-preview .bh-motion-label-tagline {
  color: color-mix(in srgb, var(--chip) 62%, rgba(240, 238, 232, 0.58));
}

.bh-motion-figure figcaption {
  padding: 10px 13px;
  border-top: 1px solid var(--line);
  color: var(--text-dim);
  font-size: 9.5px;
  line-height: 1.5;
}

.bh-motion-figure figcaption a {
  color: var(--text-soft);
  text-underline-offset: 2px;
}

.bh-motion-tooltip {
  --chip: var(--accent);
  position: absolute;
  z-index: 6;
  width: min(260px, 32%);
  padding: 10px 11px;
  border: 1px solid color-mix(in srgb, var(--chip) 52%, rgba(255, 255, 255, 0.14));
  border-radius: 9px;
  background: rgba(9, 12, 20, 0.7);
  color: #f2f2f8;
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.34);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  pointer-events: none;
}

.bh-motion-tooltip[hidden] {
  display: none;
}

.bh-motion-tooltip-tag {
  display: block;
  margin-bottom: 3px;
  color: color-mix(in srgb, var(--chip) 74%, white);
  font-size: 7.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-motion-tooltip strong {
  display: block;
  color: #fff;
  font-size: 12px;
  font-weight: 600;
  line-height: 1.25;
}

.bh-motion-tooltip-body {
  display: block;
  margin-top: 4px;
  color: rgba(240, 238, 232, 0.66);
  font-size: 9.5px;
  line-height: 1.5;
}

.bh-motion-key {
  margin-top: 12px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.bh-motion-hint {
  margin: 0 0 8px;
  color: var(--text-dim);
  font-size: 9.5px;
  line-height: 1.5;
}

.bh-motion-detail {
  display: none;
  margin: 10px 0 0;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  color: var(--text-soft);
  font-size: 11px;
  line-height: 1.6;
}

.bh-motion-guide {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.9fr);
  gap: 18px;
  margin-top: 12px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background:
    radial-gradient(110% 90% at 0% 0%, color-mix(in srgb, var(--accent) 7%, transparent), transparent 60%),
    var(--surface);
}

.bh-motion-guide-copy {
  min-width: 0;
}

.bh-motion-guide-tag {
  margin: 0 0 5px;
  color: color-mix(in srgb, var(--chip, var(--accent)) 62%, var(--text));
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.bh-motion-guide-copy h3 {
  margin: 0 0 7px;
  color: var(--text);
  font-size: 20px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

.bh-motion-guide-copy > p:last-child {
  margin: 0;
  color: var(--text-soft);
  font-size: 12px;
  line-height: 1.7;
}

.bh-motion-guide-side {
  min-width: 0;
}

.bh-motion-chips {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(125px, 1fr));
  gap: 6px;
}

.bh-motion-chip {
  appearance: none;
  display: flex;
  align-items: center;
  gap: 7px;
  min-height: 44px;
  padding: 7px 9px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text-soft);
  font: inherit;
  font-size: 9.5px;
  text-align: left;
  cursor: pointer;
}

.bh-motion-chip:hover,
.bh-motion-chip:focus-visible,
.bh-motion-chip.is-active {
  border-color: color-mix(in srgb, var(--chip) 62%, var(--line));
  background: color-mix(in srgb, var(--chip) 9%, var(--surface));
  color: var(--text);
  outline: none;
}

.bh-motion-chip-index {
  display: grid;
  place-items: center;
  width: 20px;
  height: 20px;
  flex: 0 0 auto;
  border: 1px solid color-mix(in srgb, var(--chip) 52%, var(--line));
  border-radius: 50%;
  background: color-mix(in srgb, var(--chip) 11%, var(--surface));
  color: color-mix(in srgb, var(--chip) 64%, var(--text));
  font-size: 8px;
  font-weight: 600;
  line-height: 1;
}

.bh-motion-chip-title {
  min-width: 0;
  line-height: 1.25;
}

.bh-motion-chip-dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--chip);
  box-shadow: 0 0 6px color-mix(in srgb, var(--chip) 60%, transparent);
}

.bh-motion-hint {
  margin: 0 0 8px;
  color: var(--text-dim);
  font-size: 9.5px;
  line-height: 1.5;
}

@media (max-width: 760px) {
  .bh-motion-tooltip {
    display: none !important;
  }

  .bh-motion-detail:not([hidden]) {
    display: block;
  }

  .bh-motion-chips {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .bh-motion-chip {
    font-size: 9px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .bh-motion-label,
  .bh-motion-chip,
  .bh-motion-focus,
  .bh-motion-highlight {
    transition: none;
  }

  .bh-motion-highlight-jet.is-active .bh-jet-beam,
  .bh-motion-highlight-jet.is-active .bh-jet-spine,
  .bh-motion-highlight-jet.is-active .bh-jet-flare,
  .bh-motion-highlight-jet.is-active .bh-jet-burst {
    animation: none;
  }

  .bh-motion-highlight-jet .bh-jet-particles {
    display: none;
  }
}