/**
 * 懒加载样式
 * 用于懒加载图片和内容区域的样式定义
 */

/* 懒加载图片淡入效果 */
img.lazy {
    opacity: 0;
    transition: opacity 0.5s ease-in;
}

img.lazy.loaded {
    opacity: 1;
}

/* 懒加载图片占位符效果 */
.lazy-placeholder {
    background-color: #f6f6f6;
    background-image: linear-gradient(90deg, #f6f6f6, #f0f0f0, #f6f6f6);
    background-size: 200% 100%;
    animation: placeholderShimmer 2s infinite;
    border-radius: 4px;
    position: relative;
    overflow: hidden;
}

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

/* 懒加载内容区块 */
.lazy-section {
    opacity: 0;
    transition: opacity 0.5s ease-in, transform 0.3s ease-out;
    transform: translateY(20px);
}

.lazy-section.loaded {
    opacity: 1;
    transform: translateY(0);
}

/* 懒加载错误状态 */
.lazy-section.error {
    background-color: #fff0f0;
    padding: 15px;
    border-radius: 4px;
    border: 1px solid #ffdddd;
    color: #d83030;
}

/* 加载中动画 */
.loading-spinner {
    display: inline-block;
    width: 40px;
    height: 40px;
    border: 4px solid rgba(0, 0, 0, 0.1);
    border-radius: 50%;
    border-top-color: #767676;
    animation: spin 1s ease-in-out infinite;
    margin: 20px auto;
}

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

/* 懒加载iframe */
iframe.lazy {
    opacity: 0;
    transition: opacity 0.5s ease-in;
}

iframe.lazy.loaded {
    opacity: 1;
}

/* 懒加载视频 */
video.lazy {
    opacity: 0;
    transition: opacity 0.5s ease-in;
}

video.lazy.loaded {
    opacity: 1;
}

/* 响应式图片容器 */
.responsive-image-container {
    position: relative;
    width: 100%;
    height: 0;
    overflow: hidden;
}

/* 常见的响应式比例 */
.ratio-16-9 {
    padding-bottom: 56.25%; /* 16:9 比例 */
}

.ratio-4-3 {
    padding-bottom: 75%; /* 4:3 比例 */
}

.ratio-1-1 {
    padding-bottom: 100%; /* 1:1 比例 */
}

.responsive-image-container img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* 低质量图片预览 */
.lqip {
    filter: blur(10px);
    transform: scale(1.05);
    transition: filter 0.5s ease-in, transform 0.5s ease-in;
}

.lqip.loaded {
    filter: blur(0);
    transform: scale(1);
}