/* Widget capability layer — shared across the book projects.
 *
 * This is an ADD-ON, not a full theme: it supplies the language switch and
 * every component class assets/js/viz.js's widgets render into (.viz*,
 * .ctl*, .seg, themed range sliders, details.math), plus a reduced-motion
 * override. It expects the consuming page's OWN stylesheet to already
 * define these custom properties (link this file AFTER that stylesheet):
 *
 *   --text          --border        --accent
 *   --text-muted    --viz-grid      --viz-bg
 *   --viz-a         --viz-b
 *
 * If your book's palette uses different names, alias them once, e.g.:
 *
 *   :root {
 *     --text-muted: var(--text-dim);
 *     --accent:     var(--amber);
 *     --viz-a:      var(--violet);
 *     --viz-b:      var(--cyan);
 *     --viz-grid:   var(--border);
 *     --viz-bg:     var(--bg-panel-alt);
 *   }
 *
 * See ../../docs/INTEGRATION.md for the full contract and a worked example.
 * Deliberately does not include any @media (prefers-color-scheme: dark)
 * split — if your book is single-theme, define the aliases once; if it
 * needs a light/dark split, add that override in your own stylesheet, not
 * here, since dark-only and light+dark books both consume this file as-is.
 */

/* ---------- Language switch (EN / PL) ---------- */
/* Both languages ship in the HTML; these two rules hide the inactive one, so
   the right language renders before any JS runs and with JS disabled. */
:root[data-lang="en"] [lang="pl"] { display: none; }
:root[data-lang="pl"] [lang="en"] { display: none; }

/* Only offer the switch once i18n.js has confirmed it can do something. */
.lang-switch { display: none; }

/* On bilingual pages the brand and the switch hold the top row, and the
   (longer) link list gets a row of its own underneath. Without this the
   switch wraps below the links and ends up bottom-left. */
.topnav--i18n .lang-switch { order: 2; margin-left: auto; }
.topnav--i18n .topnav__links { order: 3; flex-basis: 100%; }

:root.js .lang-switch {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 999px;
  overflow: hidden;
  background: var(--bg);
}

.lang-switch button {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  font: inherit;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  padding: 0.3rem 0.7rem;
  cursor: pointer;
  line-height: 1.4;
}

.lang-switch button:hover { color: var(--text); }

.lang-switch button.is-active {
  background: var(--accent);
  color: #fff;
}

.lang-switch button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

/* ---------- Interactive visualisation blocks ---------- */
.viz {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin: 1.75rem 0;
  overflow: hidden;
}

.viz__head {
  padding: 0.85rem 1.15rem;
  border-bottom: 1px solid var(--border);
}

.viz__title {
  font-weight: 700;
  font-size: 0.92rem;
  margin: 0;
}

.viz__sub {
  margin: 0.2rem 0 0;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.viz__stage {
  position: relative;
  background: var(--viz-bg);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 0.75rem;
}

.viz__stage--split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
}

@media (max-width: 620px) {
  .viz__stage--split { grid-template-columns: 1fr; }
}

.viz canvas {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  border-radius: 6px;
  touch-action: none;
}

.viz__controls {
  padding: 0.9rem 1.15rem 1.1rem;
  border-top: 1px solid var(--border);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 0.85rem 1.5rem;
}

.viz__legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1.1rem;
  padding: 0.6rem 1.15rem;
  font-size: 0.83rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

.viz__legend span {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

.viz__legend i {
  width: 0.85rem;
  height: 0.85rem;
  border-radius: 3px;
  display: inline-block;
  flex: none;
}

.legend-a { background: var(--viz-a); }
.legend-b { background: var(--viz-b); }
.legend-arnold { background: var(--arnold); }
.legend-pxr { background: var(--pxr); }

.viz__note {
  padding: 0.7rem 1.15rem 0.9rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
}

.viz__note p { margin: 0; }

.viz__fallback {
  padding: 1.25rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  text-align: center;
}

/* ---------- Controls ---------- */
.ctl { font-size: 0.85rem; }

.ctl__label {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.75rem;
  margin-bottom: 0.3rem;
  color: var(--text-muted);
}

.ctl__value {
  font-family: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.82rem;
  color: var(--text);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.ctl input[type="range"] {
  appearance: none;
  -webkit-appearance: none;
  width: 100%;
  height: 22px;
  background: transparent;
  cursor: pointer;
  margin: 0;
  display: block;
}

.ctl input[type="range"]::-webkit-slider-runnable-track {
  height: 4px;
  border-radius: 999px;
  background: var(--border);
}

.ctl input[type="range"]::-moz-range-track {
  height: 4px;
  border-radius: 999px;
  background: var(--border);
}

.ctl input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 15px;
  height: 15px;
  margin-top: -5.5px;
  border-radius: 999px;
  background: var(--accent);
  border: 2px solid var(--bg-elevated);
  box-shadow: 0 1px 2px rgba(0,0,0,0.25);
}

.ctl input[type="range"]::-moz-range-thumb {
  width: 15px;
  height: 15px;
  border-radius: 999px;
  background: var(--accent);
  border: 2px solid var(--bg-elevated);
  box-shadow: 0 1px 2px rgba(0,0,0,0.25);
}

.ctl input[type="range"]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 4px;
  border-radius: 999px;
}

/* Segmented toggle */
.seg {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  flex-wrap: wrap;
}

.seg button {
  appearance: none;
  border: 0;
  border-right: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  font: inherit;
  font-size: 0.8rem;
  padding: 0.3rem 0.7rem;
  cursor: pointer;
  line-height: 1.5;
}

.seg button:last-child { border-right: 0; }
.seg button:hover { color: var(--text); }

.seg button.is-active {
  background: var(--accent);
  color: #fff;
}

.seg button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.ctl--seg .ctl__label { margin-bottom: 0.4rem; }

/* Readout strip under a widget */
.readout {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem 1.5rem;
  padding: 0.6rem 1.15rem;
  border-top: 1px solid var(--border);
  font-size: 0.83rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.readout b {
  color: var(--text);
  font-family: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.82rem;
}

/* ---------- Optional maths ---------- */
details.math {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  padding: 0.6rem 1rem;
  margin: 1.25rem 0;
  font-size: 0.93rem;
}

details.math > summary {
  cursor: pointer;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--text-muted);
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

details.math > summary::-webkit-details-marker { display: none; }

details.math > summary::before {
  content: "▸";
  font-size: 0.75rem;
  transition: transform 0.15s ease;
}

details.math[open] > summary::before { transform: rotate(90deg); }
details.math[open] > summary { margin-bottom: 0.5rem; }
details.math > summary:hover { color: var(--accent); }

.formula {
  background: var(--code-bg);
  border-radius: 6px;
  padding: 0.7rem 0.9rem;
  margin: 0.75rem 0;
  overflow-x: auto;
  font-family: "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 0.84rem;
  line-height: 1.7;
  white-space: pre;
}

.formula-where {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0.4rem 0 0;
}

/* ---------- Reduced motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  details.math > summary::before { transition: none; }
}