/**
 * 尘渊文化 - 页面转场动画与加载优化
 * Page Transitions & Loading Optimizations
 * @version 1.0.0
 */

/* ========== 页面进入动画 ========== */
.page-enter {
  opacity: 0;
  transform: translateY(20px);
}

.page-enter-active {
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.4s ease, transform 0.4s ease;
}

.page-exit {
  opacity: 1;
  transform: translateY(0);
}

.page-exit-active {
  opacity: 0;
  transform: translateY(-20px);
  transition: opacity 0.3s ease, transform 0.3s ease;
}

/* ========== 页面内容淡入 ========== */
@keyframes pageFadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.page-content {
  animation: pageFadeIn 0.5s ease-out;
}

/* ========== 加载进度条 ========== */
.loading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--md-sys-color-primary), var(--md-sys-color-tertiary));
  z-index: 10000;
  transform-origin: left;
  transform: scaleX(0);
  transition: transform 0.3s ease;
}

.loading-progress.active {
  animation: loadingProgress 2s ease-in-out;
}

@keyframes loadingProgress {
  0% { transform: scaleX(0); }
  50% { transform: scaleX(0.6); }
  100% { transform: scaleX(1); }
}

/* ========== 骨架屏优化 ========== */
.skeleton {
  background: linear-gradient(
    90deg,
    var(--md-sys-color-surface-container) 25%,
    var(--md-sys-color-surface-container-high) 50%,
    var(--md-sys-color-surface-container) 75%
  );
  background-size: 200% 100%;
  animation: skeleton-loading 1.5s ease-in-out infinite;
  border-radius: var(--radius-sm);
}

@keyframes skeleton-loading {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

.skeleton-text {
  height: 1em;
  margin-bottom: 0.5em;
  border-radius: 4px;
}

.skeleton-text:last-child {
  width: 80%;
}

.skeleton-title {
  height: 1.5em;
  width: 60%;
  margin-bottom: 1em;
}

.skeleton-card {
  height: 200px;
  border-radius: var(--radius-lg);
}

.skeleton-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
}

/* ========== 渐进式图片加载 ========== */
.image-placeholder {
  background: var(--md-sys-color-surface-container);
  position: relative;
  overflow: hidden;
}

.image-placeholder::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.05),
    transparent
  );
  animation: shimmer 1.5s infinite;
}

@keyframes shimmer {
  0% { transform: translateX(-100%); }
  100% { transform: translateX(100%); }
}

.lazy-image {
  opacity: 0;
  transition: opacity 0.3s ease;
}

.lazy-image.loaded {
  opacity: 1;
}

/* ========== 内容占位符动画 ========== */
.content-placeholder {
  position: relative;
  overflow: hidden;
}

.content-placeholder::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(144, 202, 249, 0.05),
    transparent
  );
  animation: content-shimmer 2s infinite;
}

@keyframes content-shimmer {
  0% { left: -100%; }
  100% { left: 100%; }
}

/* ========== 路由过渡 ========== */
.route-transition-enter {
  opacity: 0;
  transform: scale(0.98);
}

.route-transition-enter-active {
  opacity: 1;
  transform: scale(1);
  transition: all 0.3s ease-out;
}

.route-transition-exit {
  opacity: 1;
  transform: scale(1);
}

.route-transition-exit-active {
  opacity: 0;
  transform: scale(1.02);
  transition: all 0.2s ease-in;
}

/* ========== 列表项进入动画 ========== */
.list-item-enter {
  opacity: 0;
  transform: translateX(-20px);
}

.list-item-enter-active {
  opacity: 1;
  transform: translateX(0);
  transition: all 0.3s ease;
}

/* 交错动画 */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
  animation: staggerFadeIn 0.4s ease forwards;
}

.stagger-children > *:nth-child(1) { animation-delay: 0.05s; }
.stagger-children > *:nth-child(2) { animation-delay: 0.1s; }
.stagger-children > *:nth-child(3) { animation-delay: 0.15s; }
.stagger-children > *:nth-child(4) { animation-delay: 0.2s; }
.stagger-children > *:nth-child(5) { animation-delay: 0.25s; }
.stagger-children > *:nth-child(6) { animation-delay: 0.3s; }

@keyframes staggerFadeIn {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ========== 页面加载遮罩 ========== */
.page-loader {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--md-sys-color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  transition: opacity 0.4s ease, visibility 0.4s ease;
}

.page-loader.hidden {
  opacity: 0;
  visibility: hidden;
}

.loader {
  width: 48px;
  height: 48px;
  border: 3px solid var(--md-sys-color-outline-variant);
  border-top-color: var(--md-sys-color-primary);
  border-radius: 50%;
  animation: loader-spin 1s linear infinite;
}

@keyframes loader-spin {
  to { transform: rotate(360deg); }
}

/* 加载文字 */
.loader-text {
  margin-top: 16px;
  font-size: 0.875rem;
  color: var(--md-sys-color-on-surface-variant);
  animation: pulse 1.5s ease-in-out infinite;
}

/* ========== 滚动触发动画 ========== */
.scroll-animate {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.scroll-animate.visible {
  opacity: 1;
  transform: translateY(0);
}

.scroll-animate-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.scroll-animate-left.visible {
  opacity: 1;
  transform: translateX(0);
}

.scroll-animate-right {
  opacity: 0;
  transform: translateX(30px);
  transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.scroll-animate-right.visible {
  opacity: 1;
  transform: translateX(0);
}

.scroll-animate-scale {
  opacity: 0;
  transform: scale(0.9);
  transition: all 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.scroll-animate-scale.visible {
  opacity: 1;
  transform: scale(1);
}

/* ========== 移动端优化 ========== */
@media (max-width: 768px) {
  .page-enter-active,
  .page-exit-active {
    transition-duration: 0.2s;
  }
  
  .scroll-animate,
  .scroll-animate-left,
  .scroll-animate-right {
    opacity: 1;
    transform: none;
  }
  
  .loader {
    width: 36px;
    height: 36px;
    border-width: 2px;
  }
  
  .skeleton {
    animation-duration: 1s;
  }
  
  .stagger-children > * {
    animation-delay: 0s !important;
  }
}

/* ========== 性能优化 ========== */
@media (prefers-reduced-motion: reduce) {
  .page-enter,
  .page-exit,
  .scroll-animate,
  .scroll-animate-left,
  .scroll-animate-right,
  .scroll-animate-scale {
    transition: none;
    animation: none;
    opacity: 1;
    transform: none;
  }
  
  .skeleton,
  .image-placeholder::after,
  .content-placeholder::before {
    animation: none;
  }
  
  .loader {
    animation: none;
    border: 3px solid var(--md-sys-color-primary);
  }
}

/* ========== 页面可见性API优化 ========== */
.page-hidden {
  animation-play-state: paused !important;
}

/* ========== 预加载指示器 ========== */
.preload-indicator {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  z-index: 9998;
  display: none;
}

.preload-indicator.active {
  display: block;
}

.preload-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid transparent;
  border-top-color: var(--md-sys-color-primary);
  border-radius: 50%;
  animation: preload-spin 0.8s linear infinite;
}

@keyframes preload-spin {
  to { transform: rotate(360deg); }
}