#page-header.post-bg {
  /* 关键：让背景图完整显示，不裁剪 (Contain) */
  background-size: contain !important;
  background-repeat: no-repeat !important;
  background-position: center !important;
  
  /* 兜底背景色 (深灰)，图片加载前显示 */
  background-color: #333 !important;
  
  /* 开启定位上下文 */
  position: relative;
  z-index: 1;
  
  /* 强制去除默认的 attachment，防止移动端错乱 */
  background-attachment: scroll !important;
} 


#page-header.post-bg:before {
  content: "";
  position: absolute;
  top: 0; left: 0; width: 100%; height: 100%;
  
  /* 继承父元素的 URL */
  background-image: inherit;
  
  /* 铺满模式 (Cover) */
  background-size: cover !important;
  background-position: center !important;
  
  /* 模糊 + 压暗 */
  filter: blur(20px) brightness(0.6);
  -webkit-filter: blur(20px) brightness(0.6);
  
  z-index: -1; /* 放在最底下 */
  pointer-events: none; /* 允许鼠标穿透 */
}

/* 3. 顶层 (After)：清晰的完整图片 */
#page-header.post-bg:after {
  content: "";
  position: absolute;
  top: 0; left: 0; width: 100%; height: 100%;
  
  /* 继承父元素的 URL */
  background-image: inherit;
  
  /* 完整显示模式 (Contain) */
  background-size: contain !important;
  background-repeat: no-repeat !important;
  background-position: center !important;
  
  z-index: 1; /* 放在模糊层上面 */
  pointer-events: none; /* 允许鼠标穿透 */
}

#page-header.post-bg #post-info,
#page-header.post-bg #site-info,
#nav {
  z-index: 999 !important;
  /* position: relative;
  /* 加一点文字阴影，保证在浅色图片上也看清字 */
  text-shadow: 0 0 8px rgba(0,0,0,0.6);
}