/* ==========================================================================
   动画（Animations）
   ========================================================================== */

/* 进入视口淡入 —— 初始隐藏，由 IntersectionObserver 触发 */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity var(--duration) var(--ease-out),
    transform var(--duration) var(--ease-out);
  transition-delay: var(--reveal-delay, 0s);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

/* 滚动提示线 */
.hero__scroll-line {
  display: block;
  width: 1px;
  height: 42px;
  background: linear-gradient(180deg, transparent, var(--color-text-secondary));
  animation: pulse-line 2s ease-in-out infinite;
}

@keyframes pulse-line {
  0%, 100% { opacity: 0.25; transform: scaleY(0.6); transform-origin: top; }
  50% { opacity: 1; transform: scaleY(1); transform-origin: top; }
}

/* 视差层的基础位移由 JS 驱动，这里仅保证过渡平滑 */
[data-parallax] {
  will-change: transform;
}

/* 无障碍：尊重系统“减少动态效果”偏好 */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }

  .reveal {
    opacity: 1;
    transform: none;
  }
}