/**
 * Westlife 图片加载样式 - 精简版
 * ==============================================
 * 包含：
 * 1. 缩略图淡入效果
 * 2. 文章内图片 loading 圆圈
 * 3. 文章内图片拼图遮罩效果
 * 4. 头像淡入效果
 */

/* ============================================
   1. 缩略图淡入效果 (首页 + 相关文章)
   ============================================ */

.thumb-fade {
  opacity: 0;
  transition: opacity 0.6s ease;
  /* 移除 will-change，避免与 hover transform 冲突导致卡顿 */
}

.thumb-fade.is-eager,
.thumb-fade[loading="eager"] {
  /* 首屏图片立即显示，避免等待 JS */
  opacity: 1 !important;
  transition-duration: 0.3s;
}

/* 图片加载完成后淡入 */
img.thumb-fade {
  opacity: 0;
}

img.thumb-fade[loading="lazy"] {
  /* 等待浏览器原生懒加载完成 */
  opacity: 0;
}

/* 使用 JS 或原生 load 事件触发 */
img.thumb-fade.loaded,
img.thumb-fade:not([loading]),
img.thumb-fade[loading="eager"] {
  opacity: 1;
}

/* 兜底：超过2秒未加载完成，强制显示（避免永久不可见） */
@media (prefers-reduced-motion: no-preference) {
  img.thumb-fade:not(.loaded):not([loading="eager"]):not(.is-eager) {
    animation: thumb-fade-fallback 0.6s ease-out 2s forwards;
  }
}

@keyframes thumb-fade-fallback {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

/* 缩略图比例容器 */
.thumb-ratio {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: var(--thumb-bg, #111);
}

.thumb-ratio-16x9 {
  aspect-ratio: 16 / 9;
  /* 确保有足够高度 */
  min-height: 200px;
}

.thumb-ratio img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  /* 确保图片在容器内绝对定位 */
  position: absolute;
  top: 0;
  left: 0;
}

/* ============================================
   2. 文章内图片容器 + Loading 圆圈
   ============================================ */

.wl-img-outer {
  position: relative;
  display: inline-block;
  max-width: 100%;
  vertical-align: middle;
}

/* Loading 圆圈指示器 */
.wl-img-loader {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  background: rgba(255, 255, 255, 0.35); /* 浅色磨砂 */
  backdrop-filter: blur(5px) saturate(140%);
  -webkit-backdrop-filter: blur(5px) saturate(140%);
  z-index: 2; /* 高于遮罩 */
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.wl-img-loader::before {
  content: "";
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 3px solid rgba(0, 0, 0, 0.15);
  border-top-color: var(--color-primary, #3182ce);
  animation: wl-spin 0.9s linear infinite;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.18);
  backdrop-filter: blur(2px);
}

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

/* 加载完成后隐藏 loader */
.wl-img-outer.is-loaded > .wl-img-loader {
  opacity: 0;
  visibility: hidden;
}

/* 加载失败提示 */
.wl-img-outer.is-error > .wl-img-loader {
  opacity: 0;
  visibility: hidden;
}

.wl-img-outer.is-error::after {
  content: "加载失败";
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  color: #999;
  background: #f5f5f5;
  z-index: 3;
}

/* ============================================
   3. 拼图遮罩效果 (4×4)
   ============================================ */

.puzzle-wrapper {
  position: relative;
  display: inline-block;
}

.puzzle-layer {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 1fr);
  pointer-events: none;
  z-index: 1;
}

.puzzle-piece {
  background: rgba(0, 0, 0, 0.8);
  transition: opacity 0.3s ease, transform 0.3s ease;
  transform-origin: center;
  animation: puzzleReveal 0.6s ease-out forwards;
  animation-delay: calc(var(--delay) * 30ms);
}

@keyframes puzzleReveal {
  0% {
    opacity: 1;
    transform: scale(1);
  }
  60% {
    opacity: 0.5;
    transform: scale(0.8);
  }
  100% {
    opacity: 0;
    transform: scale(0);
  }
}

/* 加载完成后移除拼图层 */
.puzzle-wrapper.is-loaded .puzzle-layer {
  animation: fadeOutLayer 0.3s ease forwards;
  animation-delay: 0.6s;
}

@keyframes fadeOutLayer {
  to {
    opacity: 0;
    visibility: hidden;
  }
}

/* ============================================
   4. 头像淡入效果
   ============================================ */

.avatar-fade,
img.avatar.avatar-fade {
  opacity: 0;
  transform: translateY(2px);
  filter: blur(2px);
  transition: opacity 0.9s ease, transform 0.9s ease, filter 0.9s ease;
}

.avatar-fade.is-in,
img.avatar.avatar-fade.is-in {
  opacity: 1;
  transform: translateY(0);
  filter: blur(0);
}

/* ============================================
   5. 响应式和辅助
   ============================================ */

@media (prefers-reduced-motion: reduce) {
  .thumb-fade,
  .avatar-fade,
  .puzzle-piece {
    animation: none !important;
    transition-duration: 0.2s !important;
  }

  .avatar-fade,
  img.avatar.avatar-fade {
    transform: none;
    filter: none;
  }

  .avatar-fade.is-in,
  img.avatar.avatar-fade.is-in {
    transform: none;
    filter: none;
  }
}

/* 深色模式适配 */
@media (prefers-color-scheme: dark) {
  .wl-img-loader {
    background: rgba(0, 0, 0, 0.5);
  }

  .wl-img-loader::before {
    border-color: rgba(255, 255, 255, 0.2);
    border-top-color: var(--color-primary, #60a5fa);
  }

  .wl-img-outer.is-error::after {
    background: #1a1a1a;
    color: #999;
  }

  .puzzle-piece {
    background: rgba(0, 0, 0, 0.9);
  }
}