/**
 * Sa Đéc Marketing Hub - Lazy Loading Styles
 * Blur-up placeholders and loading states
 */

/* ============================================================================
   IMAGE LAZY LOADING
   ============================================================================ */

.lazy-image {
    transition: opacity 0.3s ease, filter 0.3s ease;
}

.lazy-image.loading {
    opacity: 0.6;
    filter: blur(10px);
}

.lazy-image.loaded {
    opacity: 1;
    filter: blur(0);
}

.lazy-image.error {
    opacity: 1;
    filter: none;
    background: var(--md-sys-color-surface-variant, #f5f5f5);
}

/* Skeleton placeholder for images */
.image-skeleton {
    background: linear-gradient(
        90deg,
        var(--md-sys-color-surface-variant, #f0f0f0) 25%,
        var(--md-sys-color-surface-variant, #e0e0e0) 50%,
        var(--md-sys-color-surface-variant, #f0f0f0) 75%
    );
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
    border-radius: var(--md-sys-radius-medium, 8px);
}

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

/* Blur-up placeholder container */
.blur-up-container {
    position: relative;
    overflow: hidden;
    background: var(--md-sys-color-surface-variant, #f5f5f5);
}

.blur-up-container img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: opacity 0.4s ease, transform 0.4s ease;
}

.blur-up-container .placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    filter: blur(20px);
    transform: scale(1.1);
    transition: opacity 0.4s ease;
}

.blur-up-container img.loaded + .placeholder {
    opacity: 0;
}

/* ============================================================================
   CONTENT LAZY LOADING
   ============================================================================ */

.lazy-section {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

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

/* ============================================================================
   SKELETON LOADERS FOR CARDS AND COMPONENTS
   ============================================================================ */

.skeleton-card {
    background: var(--md-sys-color-surface, #ffffff);
    border-radius: var(--md-sys-radius-large, 16px);
    padding: 24px;
    overflow: hidden;
}

.skeleton-card .skeleton-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    margin-bottom: 16px;
}

.skeleton-card .skeleton-title {
    height: 24px;
    width: 60%;
    border-radius: 4px;
    margin-bottom: 12px;
}

.skeleton-card .skeleton-text {
    height: 16px;
    width: 100%;
    border-radius: 4px;
    margin-bottom: 8px;
}

.skeleton-card .skeleton-text:last-child {
    width: 80%;
    margin-bottom: 0;
}

.skeleton-card .skeleton-image {
    height: 200px;
    width: 100%;
    border-radius: var(--md-sys-radius-medium, 8px);
    margin-bottom: 16px;
}

/* Animation for all skeleton elements */
.skeleton-avatar,
.skeleton-title,
.skeleton-text,
.skeleton-image {
    background: linear-gradient(
        90deg,
        var(--md-sys-color-surface-variant, #f0f0f0) 25%,
        var(--md-sys-color-outline-variant, #e0e0e0) 50%,
        var(--md-sys-color-surface-variant, #f0f0f0) 75%
    );
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
}

/* Stagger animation for multiple skeletons */
.skeleton-card:nth-child(1) .skeleton-avatar { animation-delay: 0s; }
.skeleton-card:nth-child(2) .skeleton-avatar { animation-delay: 0.1s; }
.skeleton-card:nth-child(3) .skeleton-avatar { animation-delay: 0.2s; }
.skeleton-card:nth-child(4) .skeleton-avatar { animation-delay: 0.3s; }

/* ============================================================================
   LAZY LOADING SPINNERS
   ============================================================================ */

.lazy-spinner {
    display: inline-block;
    width: 24px;
    height: 24px;
    border: 3px solid var(--md-sys-color-surface-variant, #f0f0f0);
    border-top-color: var(--md-sys-color-primary, #006A60);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Center loader */
.lazy-loader-center {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    width: 100%;
}

/* ============================================================================
   RESPONSIVE LAZY LOADING
   ============================================================================ */

@media (max-width: 768px) {
    .lazy-section {
        transform: translateY(10px);
    }

    .skeleton-card .skeleton-image {
        height: 150px;
    }

    .lazy-spinner {
        width: 20px;
        height: 20px;
        border-width: 2px;
    }
}

/* ============================================================================
   REDUCED MOTION
   ============================================================================ */

@media (prefers-reduced-motion: reduce) {
    .lazy-image,
    .lazy-section,
    .skeleton-avatar,
    .skeleton-title,
    .skeleton-text,
    .skeleton-image {
        transition: none;
        animation: none;
    }

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