/* B-tree. The accent marks the numbers the machine computes, and nothing else.

   The layout classes here are deliberately the same shape as Race's, and that
   duplication is worth naming: four machines built in one pass all wanted a
   step label, a hint, a knob, a readout and a verdict. If a fifth wants them
   they should be promoted into the shared sheet rather than copied again. */

:root { --accent: #009999; }

/* The reading column, and the box model.
 *
 * Leaving these out is invisible in a screenshot: the browser paints a dark
 * canvas from color-scheme, so the page looks right while its column runs the
 * full width of a desktop window against the measure every other machine
 * holds. There is a gate for it, and it caught all five of these at once. */
* { margin: 0; padding: 0; box-sizing: border-box; }

main.nibble {
  max-width: var(--la-measure);
  margin: 0 auto;
  padding: 3rem 1.25rem 3rem;
}

/* The measure belongs to the column, not to every block inside it. */
main.nibble p, main.nibble ul, main.nibble ol, main.nibble dl,
main.nibble h1, main.nibble h2 { max-width: none; }

/* Leaving this out is invisible: the browser paints a dark canvas from
   color-scheme, so the page LOOKS right in a screenshot while having no
   background colour at all, and a contrast checker then measures against
   white and is correct to fail it. Seventy-nine violations per page, on
   five pages, from one missing declaration. */
body {
  font-family: var(--la-font-ui);
  background: var(--la-page);
  color: var(--la-ink);
  line-height: var(--la-leading-body);
  -webkit-font-smoothing: antialiased;
}


.bt-sr {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0;
}

.bt-steplabel { margin: var(--la-space-5) 0 var(--la-space-2); font-weight: 600; color: var(--la-ink); }
.bt-stepno {
  display: inline-block; min-width: 1.6rem; margin-right: 0.5rem;
  padding: 0.05rem 0.5rem; border: 1px solid var(--la-hairline-strong);
  border-radius: 999px; font-family: var(--la-font-mono);
  font-size: var(--la-text-xs); color: var(--la-ink-dim); text-align: center;
}
.bt-hint { margin: 0 0 var(--la-space-3); color: var(--la-ink-dim); }

.bt-knob { margin: var(--la-space-3) 0; }
.bt-knob label { display: block; margin-bottom: 0.35rem; color: var(--la-ink-dim); font-size: var(--la-text-sm); }
.bt-value { color: var(--accent); font-family: var(--la-font-mono); }
.bt-range { width: 100%; max-width: 24rem; accent-color: var(--accent); }

.bt-table { width: 100%; border-collapse: collapse; font-size: var(--la-text-sm); }
.bt-table th, .bt-table td {
  text-align: left; padding: 0.35rem 0.6rem; border-bottom: 1px solid var(--la-hairline);
}
.bt-table thead th {
  font-size: var(--la-text-xs); letter-spacing: 0.05em; text-transform: uppercase;
  color: var(--la-ink-dim); font-weight: 600;
}
.bt-table tbody th, .bt-table td {
  font-family: var(--la-font-mono); font-size: 0.8rem; color: var(--la-ink-dim); font-weight: 400;
}
/* The level that finally reaches the row count. Marked by a rule and by the
   word in its own cell, never by colour alone. */
.bt-table tr[data-reaches="yes"] td { color: var(--accent); }
.bt-table tr[data-reaches="yes"] th {
  border-left: 3px solid var(--accent); padding-left: 0.45rem; color: var(--accent);
}

.bt-readout { margin: var(--la-space-4) 0 0; }
.bt-row {
  display: flex; justify-content: space-between; gap: var(--la-space-3);
  padding: 0.4rem 0; border-bottom: 1px solid var(--la-hairline);
}
.bt-row dt { color: var(--la-ink-dim); font-size: var(--la-text-sm); }
.bt-num { font-family: var(--la-font-mono); color: var(--la-ink); margin: 0; }
.bt-row.bt-strong dd { color: var(--accent); }

.bt-verdict { margin: var(--la-space-3) 0 0; color: var(--la-ink-dim); font-size: var(--la-text-sm); }