.bc-solution-view {
  --bc-sv-forest: var(--bc-green-900, #14532d);
  --bc-sv-forest-dark: var(--bc-green-950, #0b3b2a);
  --bc-sv-teal: var(--bc-green-800, #0f766e);
  --bc-sv-mint: var(--bc-green-50, #eef8f2);
  --bc-sv-ink: var(--bc-ink, #17231d);
  --bc-sv-copy: var(--bc-copy, #34463d);
  --bc-sv-muted: var(--bc-muted, #66766e);
  --bc-sv-line: var(--bc-line, #d7e3db);
  --bc-sv-warm: #fff8e8;
  --bc-sv-warm-line: #ead7aa;
  --bc-sv-indigo: var(--bc-indigo, #506773);
  --bc-sv-indigo-dark: #3d535f;
  --bc-sv-error: #a33a3a;
  margin-top: 22px;
  overflow: hidden;
  color: var(--bc-sv-copy);
  background: #fff;
  border: 1px solid var(--bc-sv-line);
  border-top: 4px solid var(--bc-sv-forest);
  border-radius: 12px;
  box-shadow: 0 12px 32px rgba(20, 83, 45, 0.08);
  font-family: var(--bc-sans, var(--font-body, "Source Sans 3", "Noto Sans SC", system-ui, sans-serif));
  line-height: 1.6;
}

.bc-solution-view *,
.bc-solution-view *::before,
.bc-solution-view *::after { box-sizing: border-box; }
.bc-solution-view [hidden] { display: none !important; }

.bc-sv-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding: 20px 22px 17px;
  color: #fff;
  background: var(--bc-sv-forest-dark);
}

.bc-sv-header p {
  margin: 0 0 4px;
  color: #cfe8da;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.bc-sv-header h2 {
  margin: 0;
  color: #fff;
  font: 400 clamp(22px, 3vw, 30px)/1.1 var(--bc-serif, var(--font-display, Georgia, serif));
}

.bc-sv-zh {
  display: block;
  margin-top: 2px;
  color: inherit;
  font-size: 0.9em;
  font-weight: inherit;
  opacity: 0.82;
}

html[data-lang="en"] .bc-solution-view .bc-sv-zh { display: none; }

.bc-sv-meta {
  display: grid;
  grid-template-columns: minmax(180px, 1.25fr) minmax(120px, 0.55fr) minmax(240px, 1.5fr);
  gap: 1px;
  background: var(--bc-sv-line);
  border-bottom: 1px solid var(--bc-sv-line);
}

.bc-sv-meta-item {
  min-width: 0;
  padding: 12px 15px;
  background: #fff;
}

.bc-sv-meta-item.is-source { box-shadow: inset 3px 0 var(--bc-sv-teal); }
.bc-sv-meta-item.is-eligible { background: var(--bc-sv-mint); }
.bc-sv-meta-item.is-boundary { background: #f7f9f8; }
.bc-sv-meta-label,
.bc-sv-section-label {
  display: block;
  margin-bottom: 4px;
  color: var(--bc-sv-muted);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.065em;
  text-transform: uppercase;
}

.bc-sv-meta-item > strong {
  display: block;
  color: var(--bc-sv-ink);
  font-size: 12px;
  font-weight: 700;
  line-height: 1.45;
}

.bc-sv-pending {
  margin: 20px;
  padding: 18px 20px;
  color: #526159;
  background: #f7f9f8;
  border: 1px dashed #aebcb4;
  border-radius: 8px;
}

.bc-sv-pending strong {
  display: block;
  margin-bottom: 6px;
  color: var(--bc-sv-ink);
  font-family: var(--bc-serif, var(--font-display, Georgia, serif));
  font-size: 18px;
}

.bc-sv-pending p { margin: 0; font-size: 13px; }

.bc-sv-attempt {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 18px;
  padding: 18px 154px 18px 22px;
  background: #fff;
  border-bottom: 1px solid var(--bc-sv-line);
}

.bc-sv-outcome {
  position: absolute;
  top: 18px;
  right: 22px;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 11px;
  font-weight: 850;
}

.bc-sv-outcome.is-correct { color: #17603d; background: #e6f5ec; }
.bc-sv-outcome.is-incorrect { color: #8d3030; background: #fff0ee; }
.bc-sv-outcome.is-unanswered { color: #5e6b65; background: #edf1ef; }

.bc-sv-answer {
  display: flex;
  align-items: flex-start;
  gap: 9px;
  min-height: 34px;
  color: var(--bc-sv-ink);
  font-family: var(--bc-serif, var(--font-display, Georgia, serif));
  font-size: 16px;
}

.bc-sv-answer-label {
  display: inline-grid;
  flex: 0 0 28px;
  width: 28px;
  height: 28px;
  place-items: center;
  color: #fff;
  background: var(--bc-sv-teal);
  border-radius: 50%;
  font-family: var(--bc-sans, var(--font-body, system-ui, sans-serif));
  font-size: 11px;
  font-weight: 850;
}

.bc-sv-observation { margin: 0; color: var(--bc-sv-muted); font-size: 12px; }
.bc-sv-observation.is-correct { color: #17603d; }
.bc-sv-observation.is-error { color: var(--bc-sv-error); }
.bc-sv-tag-list { display: flex; flex-wrap: wrap; gap: 6px; }
.bc-sv-tag {
  padding: 4px 8px;
  color: #8d3030;
  background: #fff2f0;
  border: 1px solid #e8b9b2;
  border-radius: 5px;
  font-size: 11px;
  font-weight: 750;
}

.bc-sv-levels {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  background: #f7faf8;
  border-bottom: 1px solid var(--bc-sv-line);
}

.bc-sv-levels button {
  display: grid;
  grid-template-columns: 25px auto;
  grid-template-rows: auto auto;
  column-gap: 8px;
  align-items: center;
  justify-content: center;
  min-height: 58px;
  padding: 8px 12px;
  color: var(--bc-sv-muted);
  background: transparent;
  border: 0;
  border-right: 1px solid var(--bc-sv-line);
  cursor: pointer;
  font: 800 13px/1.2 var(--bc-sans, var(--font-body, system-ui, sans-serif));
}

.bc-sv-levels button:last-child { border-right: 0; }
.bc-sv-levels button > span {
  display: grid;
  grid-row: 1 / 3;
  width: 25px;
  height: 25px;
  place-items: center;
  color: var(--bc-sv-teal);
  background: #fff;
  border: 1px solid #b9d7ca;
  border-radius: 50%;
  font-size: 10px;
}
.bc-sv-levels button small { color: inherit; font-size: 10px; font-weight: 650; opacity: 0.78; }
.bc-sv-levels button:hover { color: var(--bc-sv-forest); background: var(--bc-sv-mint); }
.bc-sv-levels button[aria-pressed="true"] { color: #fff; background: var(--bc-sv-forest); }
.bc-sv-levels button[aria-pressed="true"] > span { color: var(--bc-sv-forest); border-color: #fff; }

.bc-sv-levels button:focus-visible,
.bc-sv-retry:focus-visible,
.bc-sv-tutor:focus-visible {
  outline: 3px solid var(--bc-sv-forest);
  outline-offset: 3px;
}

.bc-sv-tracks {
  display: grid;
  grid-template-columns: minmax(0, 1.32fr) minmax(260px, 0.88fr);
  gap: 1px;
  background: var(--bc-sv-line);
}

.bc-sv-track { min-width: 0; padding: 20px 22px 24px; background: #fff; }
.bc-sv-repair-track { background: #fbfdfc; }
.bc-sv-track-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 9px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--bc-sv-forest);
}
.bc-sv-repair-track .bc-sv-track-title { border-color: var(--bc-sv-teal); }
.bc-sv-track-title span { color: var(--bc-sv-forest); font-size: 11px; font-weight: 850; letter-spacing: 0.06em; text-transform: uppercase; }
.bc-sv-track-title strong { color: var(--bc-sv-muted); font-size: 10px; font-weight: 700; }

.bc-sv-section { padding: 14px 0; border-bottom: 1px solid var(--bc-sv-line); }
.bc-sv-section:last-child { border-bottom: 0; }
.bc-sv-section h3 {
  margin: 0 0 6px;
  color: var(--bc-sv-ink);
  font: 400 18px/1.25 var(--bc-serif, var(--font-display, Georgia, serif));
}
.bc-sv-section p { margin: 0; color: var(--bc-sv-copy); font-size: 13px; line-height: 1.65; }

.bc-sv-argument ol { display: grid; gap: 14px; margin: 12px 0 0; padding: 0; list-style: none; }
.bc-sv-argument li { display: grid; grid-template-columns: 30px minmax(0, 1fr); gap: 11px; align-items: start; }
.bc-sv-step-number {
  display: grid;
  width: 30px;
  height: 30px;
  place-items: center;
  color: #fff;
  background: var(--bc-sv-teal);
  border-radius: 6px;
  font-size: 12px;
  font-weight: 850;
}
.bc-sv-step-body {
  min-width: 0;
  overflow: hidden;
  background: #fff;
  border: 1px solid var(--bc-sv-line);
  border-radius: 8px;
}
.bc-sv-step-body h4 {
  display: flex;
  align-items: baseline;
  gap: 9px;
  margin: 0;
  padding: 10px 12px;
  color: var(--bc-sv-ink);
  background: #f7faf8;
  border-bottom: 1px solid var(--bc-sv-line);
  font: 750 13px/1.45 var(--bc-sv-sans, var(--bc-sans, system-ui, sans-serif));
}
.bc-sv-step-label {
  flex: 0 0 auto;
  color: var(--bc-sv-teal);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.045em;
  text-transform: uppercase;
}
.bc-sv-step-row { padding: 10px 12px; }
.bc-sv-step-row + .bc-sv-step-row { border-top: 1px solid #e6ece8; }
.bc-sv-step-row strong {
  display: block;
  margin-bottom: 2px;
  color: var(--bc-sv-forest);
  font-size: 10px;
  font-weight: 850;
  letter-spacing: 0.035em;
  text-transform: uppercase;
}
.bc-sv-step-row p { margin: 0; }
.bc-sv-step-row.is-why { background: #f2f8f5; }
.bc-sv-step-row.is-check { background: #fffaf0; }
.bc-sv-step-equation {
  padding: 12px 14px;
  overflow-x: auto;
  color: var(--bc-sv-ink);
  background: #fffdf8;
  border-top: 1px solid #eadfca;
  border-bottom: 1px solid #eadfca;
  font-family: var(--bc-serif, Georgia, serif);
  font-size: 15px;
}
.bc-sv-step-equation .katex-display { margin: 0.25em 0; }

.bc-sv-visual {
  margin: 14px 0 0;
  padding: 15px 16px;
  background: #f3faf6;
  border: 1px solid #c9e2d3;
  border-left: 4px solid var(--bc-sv-teal);
  border-radius: 8px;
}
.bc-sv-visual h3 { margin: 0 0 9px; color: var(--bc-sv-forest); font: 800 12px/1.35 var(--bc-sans, var(--font-body, system-ui, sans-serif)); }
.bc-sv-visual ol,
.bc-sv-visual ul,
.bc-sv-visual dl { display: grid; gap: 7px; margin: 0; padding: 0; list-style: none; }
.bc-sv-visual li,
.bc-sv-visual dl > div {
  display: grid;
  grid-template-columns: minmax(86px, 0.42fr) minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  padding: 8px 10px;
  background: #fff;
  border: 1px solid #d9e9df;
  border-radius: 6px;
}
.bc-sv-visual.is-flow ol { counter-reset: bc-sv-flow; }
.bc-sv-visual.is-flow li { position: relative; padding-left: 38px; }
.bc-sv-visual.is-flow li::before {
  counter-increment: bc-sv-flow;
  content: counter(bc-sv-flow);
  position: absolute;
  top: 8px;
  left: 9px;
  display: grid;
  width: 20px;
  height: 20px;
  place-items: center;
  color: #fff;
  background: var(--bc-sv-teal);
  border-radius: 50%;
  font-size: 9px;
  font-weight: 850;
}
.bc-sv-visual strong,
.bc-sv-visual dt { color: var(--bc-sv-forest); font-size: 11px; }
.bc-sv-visual dd { margin: 0; }
.bc-sv-visual-value { color: var(--bc-sv-copy); font-size: 12px; }
.bc-sv-visual figcaption { margin-top: 8px; color: var(--bc-sv-muted); font-size: 10px; }
.bc-sv-visual.is-plot { padding: 15px 16px 12px; background: #fff; }
.bc-sv-visual.is-plot svg { display: block; width: 100%; height: auto; overflow: visible; }
.bc-sv-visual.is-question-diagram { padding: 15px 16px 12px; background: #fff; }
.bc-sv-diagram-slot { min-height: 180px; }
.bc-sv-diagram-slot.bc-question-visual { margin: 0; border: 0; background: transparent; }
.bc-sv-plot-bg { fill: #fbfdfc; stroke: #c9d8cf; }
.bc-sv-grid { stroke: #dce7e1; stroke-width: 1; vector-effect: non-scaling-stroke; }
.bc-sv-axis { stroke: #4d5f56; stroke-width: 1.35; vector-effect: non-scaling-stroke; }
.bc-sv-tick { fill: #66766e; font: 10px/1 var(--bc-sans, system-ui, sans-serif); text-anchor: middle; }
.bc-sv-tick.is-y { text-anchor: end; }
.bc-sv-axis-label { fill: #34463d; font: 700 11px/1 var(--bc-sans, system-ui, sans-serif); text-anchor: end; }
.bc-sv-axis-label.is-y { text-anchor: start; }
.bc-sv-curve { fill: none; stroke-width: 1.9; stroke-linecap: round; stroke-linejoin: round; vector-effect: non-scaling-stroke; }
.bc-sv-curve.is-teal { stroke: #0f766e; }
.bc-sv-curve.is-indigo { stroke: var(--bc-sv-indigo); }
.bc-sv-curve.is-red { stroke: #a33a3a; }
.bc-sv-curve.is-amber { stroke: #a15c08; }
.bc-sv-curve.is-ink { stroke: #17231d; }
.bc-sv-marker circle { stroke: #fff; stroke-width: 2; vector-effect: non-scaling-stroke; }
.bc-sv-marker text { fill: #34463d; font: 700 10px/1 var(--bc-sans, system-ui, sans-serif); }
.bc-sv-marker.is-teal circle { fill: #0f766e; }
.bc-sv-marker.is-indigo circle { fill: var(--bc-sv-indigo); }
.bc-sv-marker.is-red circle { fill: #a33a3a; }
.bc-sv-marker.is-amber circle { fill: #a15c08; }
.bc-sv-marker.is-ink circle { fill: #17231d; }
.bc-sv-marker.is-open circle { fill: #fff; stroke-width: 2.5; }
.bc-sv-marker.is-open.is-teal circle { stroke: #0f766e; }
.bc-sv-marker.is-open.is-indigo circle { stroke: var(--bc-sv-indigo); }
.bc-sv-marker.is-open.is-red circle { stroke: #a33a3a; }
.bc-sv-marker.is-open.is-amber circle { stroke: #a15c08; }
.bc-sv-marker.is-open.is-ink circle { stroke: #17231d; }
.bc-sv-plot-legend { display: flex; flex-wrap: wrap; gap: 7px 14px; margin-top: 8px; color: var(--bc-sv-muted); font-size: 10px; }
.bc-sv-plot-legend > span { display: inline-flex; align-items: center; gap: 6px; }
.bc-sv-plot-legend i { display: inline-block; width: 18px; height: 3px; border-radius: 99px; background: #0f766e; }
.bc-sv-plot-legend .is-indigo i { background: var(--bc-sv-indigo); }
.bc-sv-plot-legend .is-red i { background: #a33a3a; }
.bc-sv-plot-legend .is-amber i { background: #a15c08; }
.bc-sv-plot-legend .is-ink i { background: #17231d; }

.bc-sv-formula {
  margin-top: 14px;
  padding: 17px 18px;
  background: var(--bc-sv-warm);
  border: 1px solid var(--bc-sv-warm-line);
  border-radius: 8px;
}
.bc-sv-correct-answer {
  display: grid;
  grid-template-columns: minmax(110px, 0.45fr) minmax(0, 1fr);
  gap: 12px;
  align-items: center;
  margin-top: 14px;
  padding-top: 13px;
  border-top: 1px solid var(--bc-sv-warm-line);
}
.bc-sv-correct-answer > span { color: #7c5e22; font-size: 10px; font-weight: 850; letter-spacing: 0.05em; text-transform: uppercase; }

.bc-sv-next { margin-top: 8px; padding: 14px; background: var(--bc-sv-mint); border: 1px solid #cce4d6; border-radius: 8px; }
.bc-sv-retry {
  display: inline-flex;
  align-items: center;
  min-height: 38px;
  margin-top: 11px;
  padding: 7px 12px;
  color: #fff;
  background: var(--bc-sv-forest);
  border-radius: 6px;
  text-decoration: none;
  font-size: 12px;
  font-weight: 800;
}
.bc-sv-retry:hover { color: #fff; background: var(--bc-sv-forest-dark); }

.bc-sv-tutor-wrap { margin-top: 15px; }
.bc-sv-tutor {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  width: 100%;
  min-height: 48px;
  padding: 10px 13px;
  color: #fff;
  background: var(--bc-sv-indigo);
  border: 1px solid var(--bc-sv-indigo);
  border-radius: 8px;
  cursor: pointer;
  font: 800 13px/1.25 var(--bc-sans, var(--font-body, system-ui, sans-serif));
  text-align: left;
}
.bc-sv-tutor span { display: block; font-size: 10px; font-weight: 650; opacity: 0.82; }
.bc-sv-tutor:hover { background: var(--bc-sv-indigo-dark); border-color: var(--bc-sv-indigo-dark); }
.bc-sv-tutor-note { margin: 7px 2px 0; color: #596b72; font-size: 10px; line-height: 1.5; }

.bc-solution-view .katex-display { max-width: 100%; overflow-x: auto; overflow-y: hidden; }

@media (max-width: 780px) {
  .bc-sv-meta { grid-template-columns: 1fr; }
  .bc-sv-meta-item.is-source { box-shadow: inset 3px 0 var(--bc-sv-teal); }
  .bc-sv-attempt { grid-template-columns: 1fr; padding-right: 22px; padding-top: 56px; }
  .bc-sv-outcome { left: 22px; right: auto; }
  .bc-sv-tracks { grid-template-columns: 1fr; }
  .bc-sv-track-title { align-items: flex-start; flex-direction: column; gap: 2px; }
}

@media (max-width: 520px) {
  .bc-solution-view { margin-top: 17px; border-radius: 8px; }
  .bc-sv-header { padding: 17px 16px 15px; }
  .bc-sv-meta-item,
  .bc-sv-track { padding-left: 16px; padding-right: 16px; }
  .bc-sv-pending { margin: 16px; }
  .bc-sv-attempt { padding-left: 16px; padding-right: 16px; }
  .bc-sv-outcome { left: 16px; }
  .bc-sv-levels button { grid-template-columns: 22px auto; column-gap: 5px; min-height: 62px; padding: 7px 5px; font-size: 12px; }
  .bc-sv-levels button > span { width: 22px; height: 22px; }
  .bc-sv-correct-answer { grid-template-columns: 1fr; }
  .bc-sv-argument li { grid-template-columns: 26px minmax(0, 1fr); gap: 8px; }
  .bc-sv-step-number { width: 26px; height: 26px; }
  .bc-sv-step-body h4 { align-items: flex-start; flex-direction: column; gap: 3px; }
  .bc-sv-visual li,
  .bc-sv-visual dl > div { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  .bc-solution-view *,
  .bc-solution-view *::before,
  .bc-solution-view *::after { scroll-behavior: auto !important; transition: none !important; }
}