/* Figure 4. Three paths, pairs only. Every class is prefixed br4-. Colours follow the page's tokens when present. */
.br4 {
  --x-paper: var(--br-paper, #faf8f3); --x-ink: var(--br-ink, #1d1d1b); --x-body: var(--br-body, #2a2926); --x-soft: var(--br-soft, #3c3a36);
  --x-hair: var(--br-hair, #8a8a8a); --x-c: var(--br-cyan, #009fe3); --x-c-text: var(--br-cyan-text, #0072b5);
  --x-m: var(--br-magenta, #e6007e); --x-m-text: var(--br-magenta-text, #c4006b);
  --x-ok: var(--br-holds, #0b7a3e); --x-lost: var(--br-moves, #c8401f);
  --x-rule: color-mix(in srgb, var(--x-ink) 16%, var(--x-paper));
  --x-text: var(--br-text, "InterVariable", "Inter", -apple-system, "Helvetica Neue", Arial, sans-serif);
  --x-mono: var(--br-mono, "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace);
  margin: 0; padding: clamp(.9rem, 1.8vw, 1.25rem) clamp(.9rem, 2vw, 1.4rem); background: var(--x-paper); color: var(--x-body);
  border: 1px solid var(--x-ink); font-family: var(--x-text); font-weight: 420; line-height: 1.42;
  font-optical-sizing: auto; box-sizing: border-box; position: relative;
}
@media screen and (prefers-color-scheme: dark) {
  .br4 { --x-paper: var(--br-paper, #141413); --x-ink: var(--br-ink, #faf8f3); --x-body: var(--br-body, #e9e6df); --x-soft: var(--br-soft, #c9c5bc);
    --x-c: var(--br-cyan, #2bb3f0); --x-c-text: var(--br-cyan-text, #2bb3f0); --x-m: var(--br-magenta, #ff3d9e); --x-m-text: var(--br-magenta-text, #ff5aae);
    --x-ok: var(--br-holds, #3fb871); --x-lost: var(--br-moves, #ff6a3d); }
}
.br4 *, .br4 *::before, .br4 *::after { box-sizing: border-box; }
.br4-label { margin: 0; font: 700 .7rem/1.3 var(--x-mono); letter-spacing: .14em; text-transform: uppercase; color: var(--x-soft); }
.br4-label sub { font-size: .8em; text-transform: none; letter-spacing: 0; }
.br4-head { display: flex; flex-wrap: wrap; justify-content: space-between; gap: .5rem 1rem; align-items: baseline;
  padding-bottom: .6rem; margin-bottom: .8rem; border-bottom: 1px solid var(--x-rule); }
.br4-head .br4-live { color: var(--x-ink); }
.br4-live::before { content: ""; display: inline-block; width: .5rem; height: .5rem; margin-right: .45rem; background: var(--x-m); vertical-align: .05rem; }
.br4-sub { text-transform: none; letter-spacing: .04em; font-weight: 400; font-size: .78rem; color: var(--x-body); }
.br4-plots { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 1rem; margin-top: .6rem; }
.br4-plot { min-width: 0; padding-top: .45rem; border-top: 1px solid var(--x-rule); }
.br4-plot.is-zero { border-top: 2px solid var(--x-ok); }
.br4-pname { margin: 0; font-size: .9rem; color: var(--x-ink); }
.br4-sym { font: 700 .85rem/1.3 var(--x-mono); color: var(--x-m-text); margin-right: .3rem; }
.br4-psvg { display: block; width: 100%; margin-top: .25rem; touch-action: pan-y; cursor: ew-resize; }
.br4-base { stroke: var(--x-rule); stroke-width: 1; }
.br4-gap { fill: color-mix(in srgb, var(--x-lost) 30%, transparent); stroke: none; }
.br4-three { fill: none; stroke: var(--x-ink); stroke-width: 1.6; stroke-linejoin: round; }
.br4-pairs { fill: none; stroke: var(--x-m); stroke-width: 1.6; stroke-dasharray: 5 4; stroke-linejoin: round; }
.br4-det { stroke: var(--x-c); stroke-width: 1.5; }
.br4-tick { font: 700 10.5px var(--x-mono); letter-spacing: .08em; fill: var(--x-soft); }
.br4-g { text-transform: none; font-family: var(--x-text); font-size: 1.15em; letter-spacing: 0; }
.br4-co { font-size: .78rem; color: var(--x-ok); }
.br4-pread { margin: .3rem 0 0; font: 400 .72rem/1.4 var(--x-mono); color: var(--x-body); font-variant-numeric: tabular-nums; }
.br4-pread b { font-weight: 700; color: var(--x-ink); }
.br4-pread b.is-zero { color: var(--x-ok); } .br4-pread b.is-off { color: var(--x-lost); }
.br4-slider { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 0 .4rem; align-items: center; margin-top: .8rem;
  font: 700 .62rem/1.3 var(--x-mono); letter-spacing: .12em; text-transform: uppercase; color: var(--x-soft); }
.br4-slider output { font-weight: 700; color: var(--x-c-text); font-variant-numeric: tabular-nums; font-size: .78rem; letter-spacing: .02em; text-transform: none; }
.br4-slider input { grid-column: 1 / -1; width: 100%; margin: .05rem 0 0; accent-color: var(--x-c); min-height: 26px; }
.br4 input:focus-visible { outline: 2px solid var(--x-ink); outline-offset: 2px; }
.br4-axisbox { margin-top: 1rem; padding-top: .7rem; border-top: 1px solid var(--x-ink); }
.br4-axis { display: block; width: 100%; margin-top: .3rem; overflow: visible; }
.br4-axl { stroke: var(--x-ink); stroke-width: 1; }
.br4-band { stroke: none; }
.br4-b1 { fill: color-mix(in srgb, var(--x-ok) 14%, transparent); background: color-mix(in srgb, var(--x-ok) 14%, var(--x-paper)); }
.br4-b2 { fill: color-mix(in srgb, var(--x-ok) 30%, transparent); background: color-mix(in srgb, var(--x-ok) 30%, var(--x-paper)); }
.br4-b3 { fill: color-mix(in srgb, var(--x-ok) 60%, transparent); background: color-mix(in srgb, var(--x-ok) 60%, var(--x-paper)); }
.br4-err { fill: none; stroke: var(--x-ok); stroke-width: 1.6; }
.br4-errpt { fill: var(--x-ok); }
.br4-mark circle { fill: var(--x-ok); stroke: var(--x-paper); stroke-width: 1.5; }
.br4-mark rect { fill: var(--x-lost); stroke: var(--x-paper); stroke-width: 1.5; }
.br4-mlab { font: 700 11px var(--x-mono); fill: var(--x-ink); }
.br4-bands { list-style: none; margin: .5rem 0 0; padding: 0; display: flex; flex-direction: column; gap: .15rem; font-size: .78rem; color: var(--x-soft); }
.br4-bands b { color: var(--x-ink); font: 700 .74rem/1.3 var(--x-mono); margin-right: .3rem; }
.br4-swpt { display: inline-block; min-width: 1.4rem; margin-right: .4rem; font-style: normal; font-weight: 700; color: var(--x-ok); letter-spacing: -.1em; }
.br4-sw { display: inline-block; width: .9rem; height: .7rem; margin-right: .4rem; vertical-align: -.05rem; border: 1px solid var(--x-ok); }
.br4-words { margin: .8rem 0 0; font-size: .92rem; line-height: 1.38; color: var(--x-ink); }
.br4-caption { margin: .9rem 0 0; padding-top: .7rem; border-top: 1px solid var(--x-rule); font-size: .92rem; color: var(--x-body); max-width: 52rem; }
.br4-caption b { color: var(--x-ink); font-weight: 650; }
.br4-sr { position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.br4 input { scroll-margin: 1rem 0; }
@media (max-width: 760px) { .br4-plots { grid-template-columns: minmax(0, 1fr); } }
@container br4fig (max-width: 40rem) { .br4-plots { grid-template-columns: minmax(0, 1fr); } }
@media (max-width: 480px) { .br4 { padding-left: .6rem; padding-right: .6rem; } }
@media (pointer: coarse) { .br4 input[type="range"] { min-height: 44px; } }
.br4.br4-print { --x-paper: #ffffff; --x-ink: #1d1d1b; --x-body: #2a2926; --x-soft: #3c3a36; --x-c: #009fe3; --x-c-text: #0072b5;
  --x-m: #e6007e; --x-m-text: #c4006b; --x-ok: #0b7a3e; --x-lost: #c8401f; }
@media print {
  .br4 { background: #ffffff; color: #2a2926; border-color: #1d1d1b; break-inside: avoid-page; }
  .br4 input[type="range"] { display: none; }
  .br4-plots { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: .6rem; }   /* side by side on paper, so the figure fits one page */
  .br4-pread { font-size: .62rem; }
}
@media (forced-colors: active) {
  .br4-three, .br4-axl, .br4-base { stroke: CanvasText; }
  .br4-pairs { stroke: CanvasText; } .br4-det { stroke: Highlight; }
  .br4-gap, .br4-band { fill: none; }
  .br4-mark circle, .br4-mark rect { fill: Highlight; }
  .br4-tick, .br4-mlab { fill: CanvasText; }
}
@media print {
  .br4, .br4 * { -webkit-print-color-adjust: exact; print-color-adjust: exact; }   /* drawn bars and swatches print with background graphics off */
}
/* a slider's name and its value share a line while both fit; with large text the value takes the next line */
.br4-slider { display: flex; flex-wrap: wrap; align-items: center; }
.br4-slider > span { flex: 1 1 auto; }
.br4-slider output { margin-left: auto; }
.br4-slider input { flex: 1 0 100%; }
/* the figure switches layout on its own width in the reader's text size (the @container twins of the window breakpoints) */
.br4 { container: br4fig / inline-size; }