/* ===== 滚动触发：淡入 ===== */

.anim-fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.anim-fade-in.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 滚动触发：从左滑入 ===== */

.anim-slide-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.anim-slide-left.is-visible {
  opacity: 1;
  transform: translateX(0);
}

/* ===== 滚动触发：从右滑入 ===== */

.anim-slide-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity var(--duration-slow) var(--ease-out),
              transform var(--duration-slow) var(--ease-out);
}

.anim-slide-right.is-visible {
  opacity: 1;
  transform: translateX(0);
}

/* ===== 数据条增长动画 ===== */

.anim-bar {
  width: 0;
  transition: width 800ms var(--ease-out);
}

.anim-bar.is-visible {
  /* width 由 JS 或 inline style 设置目标值 */
}

/* ===== 数字递增动画（配合 JS） ===== */

.anim-counter {
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum";
}

/* ===== 交错延迟 ===== */

.anim-stagger > *:nth-child(1)  { transition-delay: calc(var(--anim-stagger) * 0); }
.anim-stagger > *:nth-child(2)  { transition-delay: calc(var(--anim-stagger) * 1); }
.anim-stagger > *:nth-child(3)  { transition-delay: calc(var(--anim-stagger) * 2); }
.anim-stagger > *:nth-child(4)  { transition-delay: calc(var(--anim-stagger) * 3); }
.anim-stagger > *:nth-child(5)  { transition-delay: calc(var(--anim-stagger) * 4); }
.anim-stagger > *:nth-child(6)  { transition-delay: calc(var(--anim-stagger) * 5); }
.anim-stagger > *:nth-child(7)  { transition-delay: calc(var(--anim-stagger) * 6); }
.anim-stagger > *:nth-child(8)  { transition-delay: calc(var(--anim-stagger) * 7); }
.anim-stagger > *:nth-child(9)  { transition-delay: calc(var(--anim-stagger) * 8); }
.anim-stagger > *:nth-child(10) { transition-delay: calc(var(--anim-stagger) * 9); }

/* ===== 尊重用户偏好 ===== */

@media (prefers-reduced-motion: reduce) {
  .anim-fade-in,
  .anim-slide-left,
  .anim-slide-right {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .anim-bar {
    transition: none;
  }
}