/* The tails-problem explainer (DESIGN.md §7.2).
   Imported by `pages/ExplainerPage.tsx` — tokens come from widgets.css, layout
   chrome from site.css. Everything here is scoped under `.tails`, except the
   `.tails-*` figure primitives, which are only ever used inside it. */

.tails {
  --tails-measure: 68ch;
  --tails-wide: 1080px;
  font-size: 16px;
  line-height: 1.65;
}

.tails p,
.tails li {
  color: var(--text);
}

.tails a {
  color: var(--accent);
}

.tails code {
  font-size: 0.92em;
  padding: 0 3px;
  border-radius: 4px;
  background: var(--panel-2);
  border: 1px solid var(--line);
}

/* --- rule lab (the single thing at the top) ------------------------------- */

.tails-lab-grid {
  display: grid;
  grid-template-columns: minmax(300px, 470px) minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}
@media (max-width: 880px) {
  .tails-lab-grid {
    grid-template-columns: minmax(0, 1fr);
  }
}
/* Eleven columns have to fit beside the tiles without a scrollbar eating the
   verdict column, so the lab's copy of the table runs tighter than stock. */
.tails-lab .tails-table th,
.tails-lab .tails-table td {
  padding: 3px 4px;
}
.tails-lab .tails-table thead th button {
  width: 22px;
  height: 22px;
}
.tails-lab .tails-strip {
  margin-top: 0;
}
.tails-lab > .muted {
  font-size: 13px;
  margin: 10px 0 0;
}

/* A selected class shows its seams in colour on every tile of the article —
   the line coming from that edge starts by lighting the edge itself. */
.tails .tile-view .meta-edge.is-selected .edge-visual {
  opacity: 0.5;
}

/* The loose end of a hanging tail breathes, matching the patch renderer's
   fraying-end markers. */
.tails .chord-tail .tail-end {
  animation: spectre-pulse 1.6s ease-in-out infinite;
}

/* --- hero ---------------------------------------------------------------- */

.tails-hero h1 {
  font-size: clamp(30px, 6vw, 46px);
  line-height: 1.12;
  margin: 4px 0 8px;
  letter-spacing: -0.01em;
}

.tails-kicker {
  margin: 0;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-size: 12px;
  font-weight: 650;
}

.tails-lede {
  font-size: 18px;
  color: var(--muted);
  font-style: italic;
  margin: 0 0 20px;
}

.tails-toc {
  margin: 26px 0 8px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}
.tails-toc h2 {
  margin: 0 0 6px;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}
.tails-toc ol {
  margin: 0;
  padding-left: 20px;
  columns: 2;
  column-gap: 24px;
  font-size: 14px;
}
@media (max-width: 620px) {
  .tails-toc ol {
    columns: 1;
  }
}

/* --- sections ------------------------------------------------------------ */

.tails-section {
  margin: 44px 0;
  scroll-margin-top: 72px;
}
.tails-section h2 {
  font-size: 26px;
  line-height: 1.2;
  margin: 0 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--line);
}
.tails-section p {
  max-width: var(--tails-measure);
}

.tails-kernel-list {
  font-size: 17px;
  text-align: center;
  padding: 12px;
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.tails-questions {
  max-width: var(--tails-measure);
  padding-left: 20px;
}
.tails-questions li {
  margin: 8px 0;
}

.tails-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 20px 0;
}

/* --- figure frame -------------------------------------------------------- */

.tails-figure {
  margin: 26px 0;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}
.tails-figure.is-wide {
  width: min(var(--tails-wide), calc(100vw - 28px));
  margin-left: 50%;
  transform: translateX(-50%);
}
.tails-figure-head h3 {
  margin: 0;
  font-size: 15px;
  letter-spacing: 0.01em;
}
.tails-figure-hint {
  margin: 4px 0 12px;
  font-size: 13px;
  color: var(--muted);
}
.tails-figure figcaption {
  margin-top: 12px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  font-size: 13px;
  color: var(--muted);
}

/* --- controls ------------------------------------------------------------ */

.tails-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  margin-bottom: 10px;
}
.tails-controls-label {
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}
.tails-controls .edge-legend {
  margin: 0;
  border: none;
  padding: 0;
}

.tails-field {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--muted);
}
.tails-field-check {
  cursor: pointer;
}
.tails-slider input[type='range'] {
  width: min(240px, 45vw);
}

.tails-stepper {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
}
.tails-stepper button {
  width: 26px;
  height: 26px;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
  line-height: 1;
}
.tails-stepper button:disabled {
  opacity: 0.4;
  cursor: default;
}

.tails-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--muted);
  cursor: pointer;
  font-size: 13px;
}
.tails-chip:hover:not(:disabled) {
  color: var(--text);
}
.tails-chip.is-on {
  color: var(--text);
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 18%, var(--panel-2));
}
.tails-chip:disabled {
  opacity: 0.45;
  cursor: default;
}
.tails-chip-swatch {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  border: 1px solid rgba(0, 0, 0, 0.5);
}

.tails-button {
  padding: 5px 11px;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
  font-size: 13px;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
}
.tails-button.is-primary {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 22%, var(--panel-2));
}

/* --- readouts ------------------------------------------------------------ */

.tails-readouts {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 10px 0;
}
.tails-readout {
  display: flex;
  flex-direction: column;
  min-width: 84px;
  padding: 5px 9px;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--panel-2);
}
.tails-readout-label {
  font-size: 11px;
  color: var(--muted);
  text-transform: lowercase;
}
.tails-readout-value {
  font-variant-numeric: tabular-nums;
  font-size: 15px;
}
.tails-readout.is-good .tails-readout-value {
  color: var(--ok);
}
.tails-readout.is-bad .tails-readout-value {
  color: #ff8f7a;
}

.tails-note {
  margin: 10px 0;
  padding: 8px 11px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--panel-2);
  font-size: 13px;
  max-width: var(--tails-measure);
}
.tails-note.is-solved {
  border-color: var(--ok);
  color: var(--ok);
}
.tails-note.is-sad {
  border-color: #ff8f7a;
  color: #ff8f7a;
}

.tails-details {
  margin: 10px 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 8px 11px;
  background: var(--panel);
}
.tails-details summary {
  cursor: pointer;
  color: var(--muted);
  font-size: 13px;
}
.tails-details p {
  font-size: 14px;
}

/* --- layout primitives --------------------------------------------------- */

.tails-split {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(220px, 0.85fr);
  gap: 16px;
  align-items: start;
}
.tails-split.is-wide-main {
  grid-template-columns: minmax(0, 1.6fr) minmax(200px, 0.6fr);
}
.tails-split-aside h4 {
  margin: 0 0 6px;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}
.tails-split-aside p {
  font-size: 13px;
}

.tails-duo {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
  align-items: start;
}
.tails-duo-cell {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  text-align: center;
}
.tails-duo-cell h4 {
  margin: 0;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}
.tails-duo-cell p {
  font-size: 13px;
}

@media (max-width: 720px) {
  .tails-split,
  .tails-split.is-wide-main {
    grid-template-columns: minmax(0, 1fr);
  }
}

.tails-inline-tile {
  display: flex;
  gap: 10px;
  align-items: center;
  margin-top: 10px;
}
.tails-inline-tile p {
  margin: 0;
  font-size: 12px;
}

/* --- seam tally ---------------------------------------------------------- */

.tails-seam-list {
  list-style: none;
  margin: 0 0 8px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 3px;
}
.tails-seam {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 3px 7px;
  border-radius: 6px;
  border: 1px solid transparent;
  cursor: default;
  font-size: 13px;
}
.tails-seam.is-hovered {
  border-color: var(--accent);
  background: var(--panel-2);
}
.tails-seam strong {
  min-width: 34px;
  font-variant-numeric: tabular-nums;
}
.tails-seam em {
  color: var(--muted);
  font-style: normal;
  font-size: 11px;
}
.tails-seam-swatch {
  width: 10px;
  height: 10px;
  border-radius: 2px;
  border: 1px solid rgba(0, 0, 0, 0.5);
}

/* --- patches ------------------------------------------------------------- */

.tails-patch-viewport {
  position: relative;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel-2);
  overflow: hidden;
}
.tails-patch-viewport > svg.tiling-view {
  width: 100%;
  height: 100%;
}
.tails-patch-veil {
  position: absolute;
  right: 8px;
  top: 8px;
  margin: 0;
  padding: 3px 8px;
  border-radius: 999px;
  background: var(--panel);
  border: 1px solid var(--line);
  font-size: 12px;
  color: var(--muted);
}

/* --- fingerprints -------------------------------------------------------- */

.tails-fingerprint {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 6px 0;
  border-top: 1px solid var(--line);
}
.tails-fingerprint-label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-width: 110px;
  font-size: 13px;
  color: var(--muted);
}
.tails-fingerprint-types {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}
.tails-badge {
  font-size: 11px;
  padding: 2px 7px;
  border-radius: 999px;
  border: 1px solid var(--line);
  color: var(--muted);
}
.tails-badge.is-odd {
  border-color: #ff8f7a;
  color: #ff8f7a;
  background: color-mix(in srgb, #ff8f7a 14%, transparent);
}
.tails-badge.is-even {
  opacity: 0.45;
}

/* --- matrix -------------------------------------------------------------- */

.tails-table-scroll {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
}
.tails-table {
  border-collapse: collapse;
  width: 100%;
  font-variant-numeric: tabular-nums;
  font-size: 13px;
}
.tails-table caption {
  caption-side: bottom;
  padding: 6px 8px;
  font-size: 12px;
  text-align: left;
}
.tails-table th,
.tails-table td {
  padding: 4px 8px;
  text-align: center;
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
}
.tails-table thead th {
  border-bottom-width: 2px;
  border-bottom-style: solid;
}
.tails-table thead th button {
  width: 26px;
  height: 26px;
  border-radius: 6px;
  border: 1px solid var(--line);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
}
.tails-table thead th.is-selected button {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 22%, var(--panel-2));
}
.tails-table tbody th {
  text-align: left;
  color: var(--muted);
  font-weight: 500;
}
.tails-table td.is-selected {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  color: var(--text);
}
.tails-table td.is-hovered {
  outline: 1px solid var(--accent);
  outline-offset: -1px;
}
.tails-table td:not(.is-selected) {
  color: var(--muted);
}
.tails-parity-cell {
  font-weight: 700;
}
.tails-parity-cell.is-odd {
  color: #ff8f7a;
}
.tails-parity-cell.is-even {
  color: var(--ok);
}
.tails-table tbody tr.is-odd th {
  color: #ff8f7a;
}

/* --- tile strip ---------------------------------------------------------- */

.tails-strip {
  margin-top: 12px;
}
.tails-parity {
  font-size: 11px;
  color: var(--muted);
}
.tails-parity.is-odd {
  color: #ff8f7a;
}

/* --- kernel gallery ------------------------------------------------------ */

.tails-gallery-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
}
.tails-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 8px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel-2);
}
.tails-card.is-picked {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent) inset;
}
.tails-card.is-result {
  border-color: var(--ok);
  box-shadow: 0 0 0 1px var(--ok) inset;
}
.tails-card header {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 5px;
}
.tails-card-title {
  border: none;
  background: none;
  color: var(--text);
  font-size: 14px;
  font-weight: 650;
  cursor: pointer;
  padding: 0;
}
.tails-card-badge {
  font-size: 10px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 1px 6px;
}
.tails-card footer {
  font-size: 12px;
}

/* --- crossfade ----------------------------------------------------------- */

.tails-crossfade {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
}
.tails-crossfade-layer {
  position: absolute;
  inset: 0;
  opacity: 0;
  pointer-events: none;
  transition: opacity 420ms ease;
}
.tails-crossfade-layer.is-active {
  opacity: 1;
  pointer-events: auto;
}
.tails-crossfade-layer .tails-patch,
.tails-crossfade-layer .tails-patch-viewport {
  height: 100%;
}

/* --- puzzle console ------------------------------------------------------ */

.tails-console .edge-legend-chips {
  gap: 5px;
}
.tails-found {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 5px;
  margin: 6px 0;
  padding: 0;
}

@media (prefers-reduced-motion: reduce) {
  .tails-crossfade-layer {
    transition: none;
  }
  .tails .tile-view .tile-shape.is-odd {
    animation: none;
    stroke: #ff3b30;
  }
  .tails .chord-tail .tail-end {
    animation: none;
  }
}

/* Contract figure: one full-span notched slider per class, stacked. */
.tails-contract-rows {
  display: flex;
  flex-direction: column;
  gap: 6px;
  width: 100%;
}
.tails-contract-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.tails-contract-row .contract-slider {
  flex: 1 1 160px;
}
.tails-contract-row code {
  min-width: 52px;
  text-align: right;
  font-size: 12px;
  color: var(--muted);
}
.tails-contract-row.is-active code {
  color: var(--text);
}