/* ==========================================================================
   Motion — 滚动揭示、页面过渡、微交互、骨架屏（designeer.xyz 风格：克制、顺滑）
   ========================================================================== */

/* 滚动揭示：默认隐藏，进入视口后显现（由 JS 添加 .in） */
.reveal {
  opacity: 0;
  transform: translateY(18px);
  transition:
    opacity var(--dur-4) var(--ease-out),
    transform var(--dur-4) var(--ease-out);
  transition-delay: var(--reveal-delay, 0ms);
  will-change: opacity, transform;
}
.reveal.in {
  opacity: 1;
  transform: none;
}
.reveal-x { transform: translateX(-16px); }
.reveal-scale { transform: scale(0.97); }

/* 交错子元素 */
.stagger > * {
  opacity: 0;
  transform: translateY(14px);
  transition:
    opacity var(--dur-3) var(--ease-out),
    transform var(--dur-3) var(--ease-out);
}
.stagger.in > * { opacity: 1; transform: none; }
.stagger.in > *:nth-child(1) { transition-delay: 30ms; }
.stagger.in > *:nth-child(2) { transition-delay: 70ms; }
.stagger.in > *:nth-child(3) { transition-delay: 110ms; }
.stagger.in > *:nth-child(4) { transition-delay: 150ms; }
.stagger.in > *:nth-child(5) { transition-delay: 190ms; }
.stagger.in > *:nth-child(6) { transition-delay: 230ms; }
.stagger.in > *:nth-child(7) { transition-delay: 270ms; }
.stagger.in > *:nth-child(8) { transition-delay: 310ms; }
.stagger.in > *:nth-child(n + 9) { transition-delay: 350ms; }

/* 页面进入（路由切换回退动效，无 View Transitions 时使用） */
@keyframes page-in {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: none; }
}
.page-enter { animation: page-in var(--dur-3) var(--ease-out) both; }

/* View Transitions：路由切换的平滑淡入位移 */
@keyframes vt-fade-in {
  from { opacity: 0; transform: translateY(8px) scale(0.995); }
  to { opacity: 1; transform: none; }
}
@keyframes vt-fade-out {
  from { opacity: 1; }
  to { opacity: 0; transform: translateY(-6px); }
}
::view-transition-old(root) { animation: vt-fade-out var(--dur-2) var(--ease-out) both; }
::view-transition-new(root) { animation: vt-fade-in var(--dur-3) var(--ease-out) both; }

/* 通用弹入 */
@keyframes pop-in {
  0% { opacity: 0; transform: scale(0.94); }
  100% { opacity: 1; transform: scale(1); }
}
.pop-in { animation: pop-in var(--dur-2) var(--ease-spring) both; }

/* Toast */
@keyframes toast-in {
  from { opacity: 0; transform: translateY(-12px) scale(0.98); }
  to { opacity: 1; transform: none; }
}
@keyframes toast-out {
  from { opacity: 1; transform: none; }
  to { opacity: 0; transform: translateY(-8px) scale(0.98); }
}

/* 遮罩与模态 */
@keyframes mask-in { from { opacity: 0; } to { opacity: 1; } }
@keyframes modal-in {
  from { opacity: 0; transform: translateY(16px) scale(0.97); }
  to { opacity: 1; transform: none; }
}

/* 骨架屏微光 */
@keyframes shimmer {
  0% { background-position: -180% 0; }
  100% { background-position: 180% 0; }
}
.skeleton {
  background: linear-gradient(90deg, var(--surface-3) 25%, #e9e6e1 37%, var(--surface-3) 63%);
  background-size: 220% 100%;
  animation: shimmer 1.4s ease-in-out infinite;
  border-radius: var(--r-sm);
}

/* 按钮按压反馈 */
.press { transition: transform var(--dur-1) var(--ease-spring), box-shadow var(--dur-2) var(--ease-out), background-color var(--dur-1), border-color var(--dur-1), color var(--dur-1); }
.press:active { transform: scale(0.972); }

/* 强调下划线扫入（导航/链接） */
.sweep { position: relative; }
.sweep::after {
  content: "";
  position: absolute;
  left: 0; bottom: -2px;
  height: 2px; width: 100%;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--dur-2) var(--ease-out);
  border-radius: 2px;
}
.sweep:hover::after,
.sweep.active::after { transform: scaleX(1); }

/* 数字滚动计数由 JS 控制，此处保证不打断布局 */
.count-anim { font-variant-numeric: tabular-nums; }

/* 尊重「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, .stagger > * { opacity: 1 !important; transform: none !important; }
  ::view-transition-old(root), ::view-transition-new(root) { animation: none !important; }
}