/**
 * 延迟加载样式
 * 提供占位符和加载效果
 */

/* 延迟加载图片的占位符样式 */
img.lazy-loading {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading-shimmer 1.5s infinite;
    min-height: 200px;
    display: block;
    opacity: 0.7;
}

/* 延迟加载视频的占位符样式 */
video.lazy-loading {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading-shimmer 1.5s infinite;
    min-height: 300px;
    display: block;
    opacity: 0.7;
}

/* 加载动画 */
@keyframes loading-shimmer {
    0% {
        background-position: -200% 0;
    }
    100% {
        background-position: 200% 0;
    }
}

/* 加载完成后的样式 */
img.lazy-loaded,
video.lazy-loaded {
    animation: none;
    background: none;
    opacity: 1;
    transition: opacity 0.3s ease-in-out;
}

/* 加载错误样式 */
img.lazy-error,
video.lazy-error {
    background: #f8f8f8;
    border: 2px dashed #ddd;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    color: #999;
    font-size: 14px;
}

img.lazy-error::after {
    content: "图片加载失败";
}

video.lazy-error::after {
    content: "视频加载失败";
}

/* 响应式图片样式 */
.lazy-image-container {
    position: relative;
    overflow: hidden;
    border-radius: 8px;
}

.lazy-image-container img {
    width: 100%;
    height: auto;
    display: block;
}

/* 视频容器样式 */
.lazy-video-container {
    position: relative;
    overflow: hidden;
    border-radius: 8px;
    background: #000;
}

.lazy-video-container video {
    width: 100%;
    height: auto;
    display: block;
}

/* 加载指示器 */
.lazy-loading::before {
    content: "加载中...";
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #666;
    font-size: 14px;
    z-index: 1;
}

/* 暗色模式适配 */
@media (prefers-color-scheme: dark) {
    img.lazy-loading,
    video.lazy-loading {
        background: linear-gradient(90deg, #2a2a2a 25%, #3a3a3a 50%, #2a2a2a 75%);
        background-size: 200% 100%;
    }
    
    img.lazy-error,
    video.lazy-error {
        background: #1a1a1a;
        border-color: #444;
        color: #ccc;
    }
}

/* 减少动画对性能的影响 */
@media (prefers-reduced-motion: reduce) {
    img.lazy-loading,
    video.lazy-loading {
        animation: none;
        background: #f0f0f0;
    }
    
    img.lazy-loaded,
    video.lazy-loaded {
        transition: none;
    }
}