.topic-picker {
  width: min(100%, 720px);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
}
.topic-button {
  min-height: 88px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  text-align: left;
  cursor: pointer;
}
.topic-button strong,
.topic-button span { display: block; }
.topic-button strong { margin-bottom: 4px; font-size: 14px; }
.topic-button span { color: var(--muted); font-size: 12px; line-height: 1.35; }
.topic-button.active { border-color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent); }
.topic-panel[hidden] { display: none; }.coordinate-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 0.95fr);
  gap: 24px;
  align-items: start;
}
.coordinate-copy h2 {
  margin: 0 0 10px;
  font-size: 24px;
}
.coordinate-copy > .topic-panel > p {
  margin: 0 0 18px;
  color: var(--muted);
  line-height: 1.6;
}
.answer-row,
.move-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.answer-row label,
.move-grid label {
  display: grid;
  gap: 7px;
  font-size: 13px;
  font-weight: 700;
}.answer-row input,
.move-grid input {
  width: 100%;
  min-height: 46px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--surface);
  color: var(--text);
  font-size: 18px;
}
.learning-result.compact {
  margin-top: 16px;
  padding: 14px 16px;
}
.learning-result.compact:empty { display: none; }
.coordinate-visual-panel {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 11px;
  background: var(--surface-soft);
}
.coordinate-visual-panel h3 {
  margin: 0 0 12px;
  font-size: 18px;
}
.learning-visual-eyebrow {
  margin: 0 0 5px;
  color: var(--muted);
  font-size: 11px;
  font-weight: 800;
  letter-spacing: .08em;
}.coordinate-stage {
  width: 100%;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--surface);
}
.coordinate-stage svg {
  display: block;
  width: 100%;
  height: auto;
}
.axis-help {
  margin: 12px 0 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}
.coord-grid-line { stroke: var(--line); stroke-width: 1; }
.coord-axis { stroke: var(--text); stroke-width: 2.2; }
.coord-tick { fill: var(--muted); font-size: 11px; }
.coord-axis-label { fill: var(--text); font-size: 14px; font-weight: 800; }
.coord-point { fill: var(--accent); stroke: var(--surface); stroke-width: 3; }
.coord-point-old { fill: var(--muted); stroke: var(--surface); stroke-width: 3; }
.coord-point-label { fill: var(--text); font-size: 14px; font-weight: 800; }
.coord-move { stroke: var(--accent); stroke-width: 3; stroke-dasharray: 7 6; fill: none; }@media (max-width: 760px) {
  .topic-picker { grid-template-columns: 1fr; }
  .topic-button { min-height: 68px; }
  .coordinate-layout { grid-template-columns: 1fr; }
  .coordinate-visual-panel { order: -1; }
}
@media (max-width: 480px) {
  .calculator-card { padding: 18px; }
  .answer-row,
  .move-grid { grid-template-columns: 1fr; }
  .coordinate-visual-panel { padding: 14px; }
}
.explain-card {
  margin: 0 0 18px;
  padding: 14px 16px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--surface-soft);
}
.explain-card strong {
  display: block;
  margin-bottom: 7px;
}
.explain-card p,
.explain-card ol {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.55;
}
.explain-card ol {
  padding-left: 20px;
}
.explain-card li + li {
  margin-top: 4px;
}
.coord-guide {
  stroke: var(--accent);
  stroke-width: 2.5;
  stroke-dasharray: 7 5;
  fill: none;
}
.coord-origin {
  fill: var(--surface);
  stroke: var(--accent);
  stroke-width: 3;
}