/**
 * 图片加载优化样式
 * 提供渐进式加载、占位符、加载状态等视觉效果
 */

/* 图片加载状态 */
.img-loading {
    opacity: 0.3;
    filter: blur(5px);
    transition: opacity 0.3s ease, filter 0.3s ease;
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading-shimmer 1.5s infinite;
}

.img-loaded {
    opacity: 1;
    filter: blur(0);
    transition: opacity 0.5s ease, filter 0.5s ease;
}

.img-error {
    opacity: 0.5;
    filter: grayscale(100%);
}

/* 渐进式加载效果 */
.img-blur {
    filter: blur(10px);
    transition: filter 0.5s ease;
}

.img-sharp {
    filter: blur(0);
}

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

/* 图片占位符 */
.img-placeholder {
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #999;
    font-size: 14px;
}

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

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

/* 图片懒加载占位符 */
img[data-src] {
    min-height: 200px;
    background: #f0f0f0;
}

img[data-src].lazy-loaded {
    min-height: auto;
}

/* 优化图片显示 */
img {
    max-width: 100%;
    height: auto;
    display: block;
    /* 防止图片加载时的布局抖动 */
    aspect-ratio: attr(width) / attr(height);
}

/* 图片容器优化 */
.image-container {
    position: relative;
    overflow: hidden;
    background: #f5f5f5;
}

.image-container::before {
    content: '';
    display: block;
    padding-top: 56.25%; /* 16:9 比例 */
}

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

/* 关键图片优先加载 */
img[data-priority="high"] {
    loading: eager;
}

/* 非关键图片延迟加载 */
img[data-priority="low"] {
    loading: lazy;
}

/* 图片淡入效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.img-fade-in {
    animation: fadeIn 0.5s ease-in;
}