/**
 * 首页性能优化样式
 * 用于改善页面加载体验
 */

/* Banner区域初始透明度设置 */
.slider.slider-container {
    opacity: 0;
    transition: opacity 0.4s ease-in-out;
}

/* Banner加载完成后的样式 */
.slider.slider-container.loaded {
    opacity: 1;
}

/* 确保Banner在JavaScript未加载时也能显示 */
.no-js .slider.slider-container {
    opacity: 1;
}

/* 加载动画 */
.slider-loading {
    position: relative;
    min-height: 400px;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.slider-loading::before {
    content: '';
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #007bff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 图片懒加载优化 */
.lazy-image {
    opacity: 0;
    transition: opacity 0.3s ease-in-out;
}

.lazy-image.loaded {
    opacity: 1;
}

/* 预加载指示器 */
.preload-indicator {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: rgba(0, 123, 255, 0.9);
    color: white;
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 12px;
    z-index: 9999;
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.3s ease;
}

.preload-indicator.show {
    opacity: 1;
    transform: translateY(0);
}

.preload-indicator .progress {
    display: inline-block;
    margin-left: 8px;
}

/* 骨架屏样式 */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: loading 1.5s infinite;
}

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

.skeleton-text {
    height: 16px;
    margin-bottom: 8px;
    border-radius: 4px;
}

.skeleton-title {
    height: 24px;
    margin-bottom: 16px;
    border-radius: 4px;
    width: 60%;
}

.skeleton-image {
    height: 200px;
    border-radius: 8px;
    margin-bottom: 16px;
}

/* 渐进式图片加载 */
.progressive-image {
    position: relative;
    overflow: hidden;
}

.progressive-image .placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #f0f0f0;
    filter: blur(5px);
    transform: scale(1.1);
    transition: opacity 0.3s ease;
}

.progressive-image .main-image {
    opacity: 0;
    transition: opacity 0.3s ease;
}

.progressive-image.loaded .placeholder {
    opacity: 0;
}

.progressive-image.loaded .main-image {
    opacity: 1;
}

/* 响应式优化 */
@media (max-width: 768px) {
    .slider-loading {
        min-height: 250px;
    }
    
    .preload-indicator {
        bottom: 10px;
        right: 10px;
        padding: 6px 12px;
        font-size: 11px;
    }
}

/* 减少重绘和回流 */
.optimized-element {
    will-change: transform, opacity;
    transform: translateZ(0);
}

/* 关键CSS内联优化 */
.above-fold {
    /* 首屏关键样式 */
}

.below-fold {
    /* 非首屏样式可以延迟加载 */
}

/* 字体加载优化 */
@font-face {
    font-family: 'OptimizedFont';
    src: url('../fonts/font.woff2') format('woff2');
    font-display: swap;
}

/* 减少CLS (Cumulative Layout Shift) */
.aspect-ratio-container {
    position: relative;
    width: 100%;
    height: 0;
}

.aspect-ratio-16-9 {
    padding-bottom: 56.25%; /* 16:9 */
}

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

.aspect-ratio-content {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* 滚动性能优化 */
.smooth-scroll {
    scroll-behavior: smooth;
    -webkit-overflow-scrolling: touch;
}

/* 动画性能优化 */
.gpu-accelerated {
    transform: translateZ(0);
    backface-visibility: hidden;
    perspective: 1000px;
}

/* 预连接优化 */
.preconnect-hint {
    /* 通过HTML link标签实现 */
}

/* 资源提示优化 */
.prefetch-hint {
    /* 通过HTML link标签实现 */
}