.viz {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.viz-cap {
  font-size: 13px;
  color: var(--ink-2);
  text-align: center;
  line-height: 1.5;
}

/* ---------- 阵列图 ---------- */

.dot-grid {
  display: grid;
  gap: 6px;
  width: 100%;
  max-width: 420px;
}

.dot {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1;
  width: 100%;
  max-width: 40px;
  max-height: 40px;
  justify-self: center;
  align-self: center;
  border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, #d5beff 0%, var(--brand) 60%, var(--brand-d) 100%);
  border: 1.5px solid var(--brand-d);
  box-shadow: 0 2px 4px rgba(110, 68, 255, .25);
  min-height: 14px;
  font-style: normal;
  user-select: none;
  transition: transform .15s var(--ease);
}

/* 🍎 苹果皮 */
.dot.is-b {
  background: radial-gradient(circle at 35% 35%, #ffd0e6 0%, var(--accent) 62%, var(--accent-d) 100%);
  border-color: var(--accent-d);
  box-shadow: 0 2px 4px rgba(244, 114, 182, .28);
}

.dot.is-taken {
  opacity: .4;
  position: relative;
}

.dot.is-taken::after {
  content: '';
  position: absolute;
  left: 12%;
  right: 12%;
  top: 46%;
  height: 2px;
  background: #9a4a68;
  transform: rotate(-18deg);
}

.dot.dot-apple {
  background: transparent;
  border: none;
  box-shadow: none;
  border-radius: 0;
}
.dot.dot-apple::before {
  content: '🍎';
  font-size: clamp(14px, 4vw, 24px);
  line-height: 1;
  filter: drop-shadow(0 2px 3px rgba(220, 50, 50, .3));
}

/* ⭐ 闪闪星 */
.dot.dot-star {
  background: transparent;
  border: none;
  box-shadow: none;
  border-radius: 0;
}
.dot.dot-star::before {
  content: '⭐';
  font-size: clamp(13px, 3.8vw, 22px);
  line-height: 1;
  filter: drop-shadow(0 2px 3px rgba(255, 180, 0, .4));
}

/* 🍪 巧克饼 */
.dot.dot-cookie {
  background: transparent;
  border: none;
  box-shadow: none;
  border-radius: 0;
}
.dot.dot-cookie::before {
  content: '🍪';
  font-size: clamp(14px, 4vw, 24px);
  line-height: 1;
  filter: drop-shadow(0 2px 3px rgba(160, 90, 40, .35));
}

.dot.dot-apple.is-a,
.dot.dot-star.is-a,
.dot.dot-cookie.is-a {
  box-shadow: 0 0 0 3px rgba(139, 92, 246, .45);
  border-radius: 12px;
}

.dot.dot-apple.is-b,
.dot.dot-star.is-b,
.dot.dot-cookie.is-b {
  box-shadow: 0 0 0 3px rgba(244, 114, 182, .6);
  border-radius: 12px;
}

.viz-array.anim .dot {
  animation: pop .32s var(--ease) both;
  animation-delay: calc(var(--i, 0) * var(--stagger, 40ms));
}

/* ---------- 等组图 ---------- */

.group-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  width: 100%;
}

.group {
  border: 2px dashed var(--accent);
  border-radius: 14px;
  background: var(--accent-l);
  padding: 8px 10px 6px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}

.group-dots {
  display: grid;
  gap: 5px;
  justify-content: center;
}

.group-dots .dot {
  width: 22px;
  max-width: 22px;
  min-height: 22px;
  max-height: 22px;
  background: radial-gradient(circle at 35% 35%, #d5beff 0%, var(--brand) 60%, var(--brand-d) 100%);
  border-color: var(--brand-d);
}

.group-dots .dot.dot-apple,
.group-dots .dot.dot-star,
.group-dots .dot.dot-cookie {
  background: transparent;
  border: none;
  box-shadow: none;
}
.group-dots .dot.dot-apple::before,
.group-dots .dot.dot-star::before,
.group-dots .dot.dot-cookie::before {
  font-size: 16px;
}

.group-label {
  font-size: 11px;
  color: var(--accent-d);
}

.viz-groups.anim .group {
  animation: pop .34s var(--ease) both;
  animation-delay: calc(var(--gi, 0) * var(--gstagger, 160ms));
}

.viz-groups.anim .group .dot {
  animation: pop .3s var(--ease) both;
  animation-delay: calc(var(--gi, 0) * var(--gstagger, 160ms) + var(--i, 0) * var(--stagger, 35ms));
}

/* ---------- 数轴跳格 ---------- */

.nl-scroll {
  width: 100%;
  overflow-x: auto;
  text-align: center;
}

.nl-svg {
  display: inline-block;
  max-width: none;
  height: auto;
}

.nl-axis { stroke: var(--axis); stroke-width: 2; }
.nl-minor { stroke: var(--axis-minor); stroke-width: 1.5; }
.nl-major { stroke: var(--axis-major); stroke-width: 2; }

.nl-num {
  font-family: var(--font-num);
  font-size: 14px;
  fill: var(--ink);
}

.nl-plus {
  font-family: var(--font-num);
  font-size: 13px;
  font-weight: 500;
  fill: var(--accent-d);
}

.nl-arc {
  stroke: var(--accent);
  stroke-width: 3;
  stroke-linecap: round;
  vector-effect: non-scaling-stroke;
}

.nl-ball {
  fill: var(--brand);
  stroke: var(--brand-d);
  stroke-width: 1.5;
  vector-effect: non-scaling-stroke;
}

.nl-ball-start { fill: var(--card); }

.viz-nl.anim .nl-arc {
  stroke-dasharray: var(--len, 200);
  stroke-dashoffset: var(--len, 200);
  animation: draw .4s ease-out both;
  animation-delay: calc(var(--i, 0) * var(--jstagger, 160ms));
}

.viz-nl.anim .nl-ball {
  animation: hop .42s cubic-bezier(.34, 1.4, .64, 1) both;
  animation-delay: calc((var(--i, 0) + 1) * var(--jstagger, 160ms));
  transform-box: fill-box;
  transform-origin: center;
}

.viz-nl.anim .nl-plus {
  animation: pop .3s var(--ease) both;
  animation-delay: calc(var(--i, 0) * var(--jstagger, 160ms));
}

/* ---------- 面积模型（作用域限定，避免影响口诀表格子） ---------- */

.area-grid {
  display: grid;
  gap: 3px;
  width: 100%;
  max-width: 420px;
}

.ax {
  font-family: var(--font-num);
  font-size: 11px;
  color: var(--ink-3);
  display: flex;
  align-items: center;
  justify-content: center;
}

.area-grid .cell {
  border: 1.5px solid var(--brand);
  border-radius: 4px;
  background: var(--brand-l);
  min-height: 12px;
}

.viz-area.anim .cell {
  animation: pop .28s var(--ease) both;
  animation-delay: calc(var(--i, 0) * var(--stagger, 40ms));
}

/* ---------- 并排四图 ---------- */

.viz-all {
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
  width: 100%;
}

.viz-card {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--card);
  padding: 8px 10px 10px;
}

.viz-card-title {
  font-size: 12px;
  color: var(--ink-3);
  margin-bottom: 6px;
}

.viz-card-body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 90px;
}

.viz-card .dot-grid { max-width: 300px; }
.viz-card .area-grid { max-width: 300px; }
.viz-card .group-dots .dot { width: 16px; max-width: 16px; min-height: 16px; max-height: 16px; }
.viz-card .group { padding: 6px 8px 4px; }

@media (min-width: 640px) {
  .viz-all { grid-template-columns: 1fr 1fr; }
}