/**
 * 性能优化和 UX 改进样式
 */

/* ========== 图片懒加载样式 ========== */
.lazy-image {
    opacity: 0;
    transition: opacity 0.3s ease;
}

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

.lazy-image.lazy-error {
    opacity: 1;
    background: linear-gradient(135deg, #f0f0f0 0%, #e0e0e0 100%);
}

/* ========== 图片容器和骨架屏 ========== */
.image-container {
    position: relative;
    overflow: hidden;
    background: #f5f5f5;
    border-radius: 8px;
}

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

.image-skeleton {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(
        90deg,
        #f0f0f0 25%,
        #e0e0e0 50%,
        #f0f0f0 75%
    );
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
}

.image-container .lazy-loaded + .image-skeleton {
    display: none;
}

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

/* ========== 页面加载动画 ========== */
.page-loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #fff;
    z-index: 9999;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.page-loader.hidden {
    opacity: 0;
    visibility: hidden;
}

.loader-spinner {
    width: 50px;
    height: 50px;
    border: 3px solid #f0f0f0;
    border-top-color: var(--primary, #4CAF50);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* ========== 平滑滚动 ========== */
html {
    scroll-behavior: smooth;
}

/* ========== 卡片悬停效果优化 ========== */
.product-card,
.term-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    will-change: transform;
}

.product-card:hover,
.term-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

/* ========== 按钮点击效果 ========== */
.btn,
.filter-btn {
    transition: all 0.2s ease;
    position: relative;
    overflow: hidden;
}

.btn:active,
.filter-btn:active {
    transform: scale(0.95);
}

/* ========== 表单输入焦点效果 ========== */
input:focus,
textarea:focus,
select:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(var(--primary-rgb, 76, 175, 80), 0.2);
}

/* ========== 移动端优化 ========== */
@media (max-width: 768px) {
    /* 增大点击区域 */
    .navbar-menu a,
    .filter-btn,
    .lang-switch a {
        min-height: 44px;
        display: flex;
        align-items: center;
        justify-content: center;
    }
    
    /* 防止字体过小 */
    body {
        font-size: 16px;
    }
    
    /* 优化触摸滚动 */
    .terms-grid,
    .products-grid {
        -webkit-overflow-scrolling: touch;
    }
    
    /* 减少动画（尊重用户偏好） */
    @media (prefers-reduced-motion: reduce) {
        *,
        *::before,
        *::after {
            animation-duration: 0.01ms !important;
            animation-iteration-count: 1 !important;
            transition-duration: 0.01ms !important;
        }
    }
}

/* ========== 暗色模式支持（预留） ========== */
@media (prefers-color-scheme: dark) {
    /* 可以添加暗色模式样式 */
}

/* ========== 打印优化 ========== */
@media print {
    .navbar,
    .page-loader,
    .back-to-top,
    .filter-btn {
        display: none !important;
    }
    
    body {
        background: white !important;
        color: black !important;
    }
}