:root {
  --train: #bfdbfe;
  --train-ink: #1d4ed8;
  --test: #bbf7d0;
  --test-ink: #15803d;
  --wrong: #b91c1c;
  --ink: #1c2230;
  --muted: #5d6677;
  --bg: #f4f5f8;
  --card: #fff;
  --line: #e3e6ec;
  --radius: 14px;
  /* Class colors, as in the binary metrics demo. */
  --c0: #0a66ff;
  --c1: #ff6b00;
  --model: #7c3aed;
}
* { box-sizing: border-box; }

body {
  margin: 0;
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", Roboto,
    "Helvetica Neue", sans-serif;
  color: var(--ink);
  background: var(--bg);
}

header, main, footer {
  max-width: 1360px;
  margin: 0 auto;
  padding-left: 24px;
  padding-right: 24px;
}
header { padding-top: 28px; padding-bottom: 6px; }
h1 { font-size: 2rem; margin: 0 0 2px; letter-spacing: -0.015em; }
.sub { color: var(--muted); margin: 0; font-size: 1.05rem; }

.tabs { display: flex; gap: 8px; margin-top: 18px; }
.tab {
  font: inherit;
  font-weight: 600;
  color: var(--muted);
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 7px 18px;
  cursor: pointer;
}
.tab:hover { color: var(--ink); }
.tab[aria-selected="true"] {
  background: var(--ink);
  border-color: var(--ink);
  color: #fff;
}

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: 0 1px 2px rgba(16, 24, 40, .04),
    0 6px 20px rgba(16, 24, 40, .05);
}
.side { display: flex; flex-direction: column; gap: 14px; }
.side .card { padding: 16px 18px; }
.card h2 { font-size: 1.12rem; margin: 0 0 8px; }
.card h3 {
  font-size: .75rem;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--muted);
  margin: 12px 0 6px;
}
.side .readout h3 { margin-top: 0; }
.card h3 i { text-transform: none; letter-spacing: 0; font-size: 1.1em; }
.card p { margin: 0 0 10px; }
.formula {
  font-family: "STIX Two Text", "Cambria", Georgia, serif;
  font-size: 1.1rem;
  text-align: center;
  background: #f6f7fa;
  border-radius: 10px;
  padding: 10px;
  margin: 6px 0 10px;
}
.formula b { font-family: system-ui, sans-serif; }
.implies { margin: 0 .45em; color: var(--muted); }
.frac {
  display: inline-flex;
  flex-direction: column;
  vertical-align: middle;
  text-align: center;
  line-height: 1.25;
}
.frac > span:first-child {
  border-bottom: 1.3px solid currentColor;
  padding: 0 .25em 1px;
}
.frac > span:last-child { padding-top: 1px; }
ul.try { margin: 0 0 10px; padding-left: 1.1em; }
ul.try li { margin: 3px 0; }
.answer { margin: 4px 0 2px; }
.answer summary {
  cursor: pointer;
  color: var(--train-ink);
  font-weight: 600;
  width: max-content;
}
.answer[open] {
  background: #f6f7fa;
  border-radius: 8px;
  padding: 4px 10px 6px;
}
.readout { font-variant-numeric: tabular-nums; }
.readout .row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding: 5px 0;
  border-bottom: 1px dashed var(--line);
}
.readout .row:last-child { border-bottom: 0; }
.readout .val { font-weight: 600; white-space: nowrap; }
.muted { color: var(--muted); font-size: .88em; }
.buttons { display: flex; flex-wrap: wrap; gap: 8px; margin: 4px 0 10px; }
button:not(.tab) {
  font: inherit;
  font-size: .92rem;
  font-weight: 600;
  color: var(--ink);
  background: #fff;
  border: 1px solid #cfd4dd;
  border-radius: 8px;
  padding: 5px 12px;
  cursor: pointer;
}
button:not(.tab):hover { background: #f3f4f7; }
button:not(.tab):active { background: #e9ebf0; }
footer {
  padding-top: 4px;
  padding-bottom: 28px;
  color: var(--muted);
  font-size: .9rem;
}
footer a { color: inherit; }
.warn {
  color: #9a3412;
  background: #fff7ed;
  border-radius: 8px;
  padding: 6px 9px;
  margin: 6px 0;
  font-size: .92rem;
}

.intro {
  max-width: 1312px;
  margin: 12px auto 0;
  padding: 16px 20px 6px;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  gap: 8px 32px;
}
.intro .card h3, .intro h3 { margin-top: 2px; }
.intro .formula { margin-bottom: 8px; }
.goal {
  background: #f3f6ff;
  border-left: 3px solid var(--train-ink);
  border-radius: 0 8px 8px 0;
  padding: 7px 11px;
}
.goal.approach { background: #f0fdf4; border-left-color: var(--test-ink); }
.notation {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 10px;
  margin: 0 0 10px;
}
.notation .labels { display: inline-flex; flex-wrap: wrap; gap: 6px; }
.notation .labels > span {
  font-weight: 650;
  background: #f1f3f7;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 1px 10px;
}
.notation i, .formula i { font-family: "STIX Two Text", Georgia, serif; }

/* ------------------------------------------------------------ controls */
.controls { display: flex; flex-direction: column; gap: 10px; }
.slider, .field {
  display: grid;
  grid-template-columns: 70px minmax(0, 1fr);
  align-items: center;
  gap: 2px 10px;
  margin: 0;
}
.slider input { accent-color: var(--ink); margin: 0; }
/* Own line under the slider, so its changing width cannot resize it. */
.slider .val {
  grid-column: 2;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  font-size: .92rem;
}
.check input { accent-color: var(--ink); margin: 0; }
.controls .buttons { margin: 0; }
.controls .buttons button { flex: 1; }
.seg {
  display: flex;
  border: 1px solid #cfd4dd;
  border-radius: 8px;
  overflow: hidden;
}
.seg.wrap { flex-wrap: wrap; border: 0; gap: 6px; overflow: visible; }
.seg button {
  flex: 1;
  border: 0 !important;
  border-radius: 0 !important;
  padding: 5px 8px !important;
}
.seg.wrap button {
  flex: 0 1 auto;
  border: 1px solid #cfd4dd !important;
  border-radius: 999px !important;
  padding: 3px 11px !important;
}
.seg:not(.wrap) button + button { border-left: 1px solid #cfd4dd !important; }
.seg button[aria-checked="true"] {
  background: var(--ink) !important;
  border-color: var(--ink) !important;
  color: #fff;
}

.formula .sep { display: inline-block; width: 1.6em; }
.status { margin: 8px 0 0; font-weight: 600; }
/* Column vector: entries stacked between square brackets. */
.colvec {
  position: relative;
  display: inline-flex;
  flex-direction: column;
  vertical-align: middle;
  align-items: flex-end;
  padding: 1px .45em;
  line-height: 1.25;
}
.colvec .vdots { align-self: center; line-height: 1; }
.colvec::before, .colvec::after {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  width: .28em;
  border: 1.5px solid currentColor;
}
.colvec::before { left: 0; border-right: 0; }
.colvec::after { right: 0; border-left: 0; }
.status.converged { color: var(--test-ink); }
.status.diverged { color: var(--wrong); }
.status.capped { color: #9a3412; }
.status.hovering { color: #ea580c; }
button.primary {
  background: var(--ink) !important;
  border-color: var(--ink) !important;
  color: #fff !important;
}
button:disabled { opacity: .45; cursor: default; }
.checks { display: grid; grid-template-columns: 1fr 1fr; gap: 6px 10px; }
.check { font-size: .92rem; }
.check input:disabled + * , .check:has(input:disabled) { color: #aab1bd; }
.field > span, .slider > span:first-child { font-size: .92rem; }
.seg.small button { padding: 2px 10px !important; font-size: .82rem; }

/* Hover (or focus) explanation on a control's name. */
.tip {
  position: relative;
  cursor: help;
  text-decoration: underline dotted #8a93a3;
  text-underline-offset: 3px;
}
.tip:hover::after, .tip:focus::after {
  content: attr(data-tip);
  position: absolute;
  z-index: 10;
  left: 0;
  top: calc(100% + 6px);
  width: 290px;
  padding: 8px 10px;
  border-radius: 8px;
  background: var(--ink);
  color: #fff;
  font-size: .82rem;
  font-style: normal;
  line-height: 1.4;
  white-space: normal;
  box-shadow: 0 6px 20px rgba(16, 24, 40, .18);
}
main { padding-top: 14px; padding-bottom: 24px; }
.panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr) 340px;
  gap: 16px;
  align-items: start;
}
[hidden] { display: none !important; }
.panel > * { min-width: 0; }
.panel.reg > .side { grid-column: 3; grid-row: 1 / span 2; }
.below { padding: 14px 16px; }
.seg.tight button { padding: 5px 4px !important; font-size: .86rem; }
.controls .buttons button { white-space: nowrap; padding: 5px 9px;
  font-size: .88rem; flex: 1 1 auto; }
.col { display: flex; flex-direction: column; gap: 14px; }
.col .card { padding: 14px 16px; }
.plot { padding: 10px 12px 8px; }
.plot svg {
  display: block;
  width: 100%;
  height: auto;
  max-height: calc(100vh - 150px);
  touch-action: none;
  user-select: none;
}
.plot-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 4px;
}
.plot-head h3 { margin: 2px 0; }
.eq { font-family: "STIX Two Text", Georgia, serif; font-size: 1.05rem; }
.hint { margin: 4px 2px 0; color: var(--muted); font-size: .86rem; }
.chart { display: block; width: 100%; height: auto; }

/* ----------------------------------------------------------------- SVG */
.grid { stroke: #edf0f4; stroke-width: 1; }
.frame { fill: none; stroke: #a3abb9; stroke-width: 1.2; }
.tick { fill: #8a93a3; font-size: 13px; }
.chart .tick { font-size: 11px; }
.axis-label { fill: var(--muted); font-size: 16px; }
.chart .axis-label { font-size: 12px; }
.sym { font-family: "STIX Two Text", Georgia, serif; font-style: italic; }
svg.orbit { cursor: grab; }
.here-level {
  fill: none;
  stroke: var(--ink);
  stroke-width: 2;
  stroke-opacity: .75;
  pointer-events: none;
}
.lockline {
  stroke: #ea580c;
  stroke-width: 1.5;
  stroke-dasharray: 6 4;
  pointer-events: none;
}
.clabel {
  font-size: 11.5px;
  fill: #33415c;
  paint-order: stroke;
  stroke: #eef2f9;
  stroke-width: 3.5px;
  stroke-linejoin: round;
  pointer-events: none;
}
.hover-ring { fill: none; stroke: #ea580c; stroke-width: 2.5;
  pointer-events: none; }
.mark { stroke: #ea580c; stroke-width: 1.2; stroke-dasharray: 3 3; }
.axis0 { stroke: #1c2230; stroke-opacity: .25; stroke-width: 1; }
.trail {
  fill: none;
  stroke: var(--ink);
  stroke-width: 2;
  stroke-linejoin: round;
  pointer-events: none;
}
.trail-dot { fill: #fff; stroke: var(--ink); stroke-width: 1.5;
  pointer-events: none; }
.step line { stroke: #ea580c; stroke-width: 3; }
.step polygon { fill: #ea580c; }
.grad line { stroke: var(--ink); stroke-width: 2; stroke-dasharray: 5 4; }
.grad polygon { fill: var(--ink); }
.offplot line { stroke: var(--wrong); stroke-width: 3; }
.offplot polygon { fill: var(--wrong); }
.step, .grad, .offplot { pointer-events: none; }
.handle {
  fill: var(--model);
  stroke: #fff;
  stroke-width: 2.5;
  cursor: move;
}
.handle:hover { stroke: var(--ink); }
.surf-pt { fill: var(--ink); stroke: #fff; stroke-width: 2;
  pointer-events: none; }
.dropline { stroke: var(--ink); stroke-width: 1.5; stroke-dasharray: 4 3; }
.tip-label, .arrow-label {
  font-size: 14px;
  font-weight: 600;
  fill: var(--ink);
  paint-order: stroke;
  stroke: #fff;
  stroke-width: 4px;
  stroke-linejoin: round;
  pointer-events: none;
}
.arrow-label { font-size: 13px; }
.floor polygon { fill: #f6f7fa; stroke: #a3abb9; stroke-dasharray: 4 3; }
.mesh polygon { fill-opacity: .78; stroke: #fff; stroke-opacity: .5;
  stroke-width: .6; }

/* Data panels */
.lh { fill: #fff; stroke: var(--model); stroke-width: 2.5;
  cursor: ns-resize; }
.lh:hover { fill: #ede9fe; }

/* Loss chart */
.loss { fill: none; stroke: var(--ink); stroke-width: 2;
  stroke-linejoin: round; }
.loss-dot { fill: #ea580c; }

@media (max-width: 1360px) {
  .intro { margin-left: 24px; margin-right: 24px; }
}
@media (max-width: 1240px) {
  .panel { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .panel > .side, .panel.reg > .side { grid-column: 1 / -1; grid-row: auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
}
@media (max-width: 820px) {
  .panel, .intro { grid-template-columns: 1fr; }
}
@media (max-width: 520px) {
  header, main, footer { padding-left: 16px; padding-right: 16px; }
  .intro { margin-left: 16px; margin-right: 16px; }
}
#tr-run { flex: 0 0 92px; }

.bands { image-rendering: auto; cursor: crosshair; }
.flevel { fill: none; stroke: rgba(40, 60, 100, .35); stroke-width: 1; }
.here-level { fill: none; }

/* Samples: filled by true class, ringed by predicted class. */
.s { stroke-width: 3; cursor: pointer; }
.s.k0 { fill: var(--c0); }
.s.k1 { fill: var(--c1); }
.s.p0 { stroke: var(--c0); }
.s.p1 { stroke: var(--c1); }
.s:hover, .s.on { r: 9px; }
.phat { fill: #fff; stroke-width: 1.6; pointer-events: none; }
.phat.k0 { stroke: var(--c0); }
.phat.k1 { stroke: var(--c1); }
.err { stroke: #dc2626; stroke-width: 1.8; stroke-opacity: .55;
  pointer-events: none; }
.curve { fill: none; pointer-events: none; stroke-linejoin: round; }
.curve.model { stroke: var(--model); stroke-width: 3; }
.curve.best { stroke: var(--ink); stroke-width: 2; stroke-dasharray: 7 5;
  stroke-opacity: .6; }
.curve.truth { stroke: #15803d; stroke-width: 2.5; stroke-dasharray: 1 5;
  stroke-linecap: round; }
.dp-bg { fill: transparent; cursor: ew-resize; }
.odds .dp-bg { cursor: ns-resize; }
.zero { stroke: var(--ink); stroke-opacity: .35; stroke-width: 1.2;
  pointer-events: none; }
.bound { stroke: var(--ink); stroke-opacity: .35; stroke-width: 1.2;
  pointer-events: none; }
.bound-label { font-size: 12px; fill: var(--muted); pointer-events: none; }
.ptick { font-size: 12px; }
.axis-label.small { font-size: 13px; }

/* Legend under a data panel. */
.key {
  display: flex;
  flex-wrap: wrap;
  gap: 2px 14px;
  margin: 4px 2px 0;
  color: var(--muted);
  font-size: .84rem;
}
.key > span { display: inline-flex; align-items: center; gap: 5px; }
.key .dot {
  display: inline-block;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  border: 2.5px solid transparent;
}
.key .dot.k0 { background: var(--c0); border-color: var(--c0); }
.key .dot.k1 { background: var(--c1); border-color: var(--c1); }
.key .dot.p1 { border-color: var(--c1); }
.key .ln { display: inline-block; width: 24px; border-top: 3px solid; }
.key .ln.model { border-color: var(--model); }
.key .ln.best { border-top: 2px dashed #8a93a3; }
.key .ln.truth { border-top: 3px dotted #15803d; }
.key .ln.err { width: 3px; height: 14px; border-top: 0;
  background: #dc2626; opacity: .6; }
.s.raw { stroke: #fff; stroke-width: 1.5; }
.s.raw.on { stroke: var(--ink); stroke-width: 2; }
.lane { stroke: #cfd4dd; stroke-width: 1; }
.readoff { fill: none; stroke: var(--model); stroke-width: 1.5;
  stroke-dasharray: 2 3; pointer-events: none; }
.panel.model > .strip { grid-column: 1 / 3; }
.panel.model > .side { grid-column: 3; grid-row: 1 / span 2; }
.strip svg { max-height: none; }
.pipe {
  margin: 4px 2px 0;
  font-size: .95rem;
  min-height: 3.4em;
}
.pipe i, .pipe .m { font-family: "STIX Two Text", Georgia, serif; }
.pipe .arr { color: var(--muted); margin: 0 .35em; }
.goal.problem { background: #fef2f2; border-left-color: var(--wrong); }
@media (max-width: 1240px) {
  .panel.model > .strip, .panel.model > .side { grid-column: 1 / -1;
    grid-row: auto; }
}
.fo-label { overflow: visible; pointer-events: none; }
.axis-html {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
  white-space: nowrap;
  color: var(--muted);
  font: 17px/1.2 "STIX Two Text", Georgia, serif;
  word-spacing: .1em;
}
.lh.ew { cursor: ew-resize; }
.zaxis .xonly { display: none; }
.plot-head .eq { margin-left: auto; }