/**
 * Article Card Animations
 * Stagger animations and smooth transitions for article cards
 * Requirements: 9.2, 9.3
 */

/* Fade-in Stagger Animation */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Apply stagger animation to article cards in grid */
.articles-grid .content-card {
    animation: fadeInUp 0.5s ease-out backwards;
}

/* Stagger delays for sequential appearance */
.articles-grid .content-card:nth-child(1) {
    animation-delay: 0ms;
}

.articles-grid .content-card:nth-child(2) {
    animation-delay: 50ms;
}

.articles-grid .content-card:nth-child(3) {
    animation-delay: 100ms;
}

.articles-grid .content-card:nth-child(4) {
    animation-delay: 150ms;
}

.articles-grid .content-card:nth-child(5) {
    animation-delay: 200ms;
}

.articles-grid .content-card:nth-child(6) {
    animation-delay: 250ms;
}

.articles-grid .content-card:nth-child(7) {
    animation-delay: 300ms;
}

.articles-grid .content-card:nth-child(8) {
    animation-delay: 350ms;
}

.articles-grid .content-card:nth-child(9) {
    animation-delay: 400ms;
}

.articles-grid .content-card:nth-child(10) {
    animation-delay: 450ms;
}

.articles-grid .content-card:nth-child(11) {
    animation-delay: 500ms;
}

.articles-grid .content-card:nth-child(12) {
    animation-delay: 550ms;
}

/* For cards beyond 12, use a general rule */
.articles-grid .content-card:nth-child(n+13) {
    animation-delay: 600ms;
}

/* Hero Section Animation */
.article-hero {
    animation: fadeInUp 0.6s ease-out backwards;
}

/* Category Hero Animation */
.category-hero {
    animation: fadeInUp 0.6s ease-out backwards;
}

/* Sidebar Animation */
.articles-sidebar,
.articles-sidebar-enhanced {
    animation: fadeInUp 0.7s ease-out backwards;
    animation-delay: 200ms;
}

/* Filter UI Animation */
.article-filters,
.article-filters-advanced {
    animation: fadeInUp 0.5s ease-out backwards;
    animation-delay: 100ms;
}

/* Smooth Transitions for Interactive Elements */

/* Content Card Hover Effects */
.content-card {
    transition: transform 250ms ease-in-out, box-shadow 250ms ease-in-out;
}

.content-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg, 0 10px 25px rgba(0, 0, 0, 0.15));
}

/* Card Image Hover */
.content-card__cover-link {
    overflow: hidden;
}

.content-card__image {
    transition: transform 300ms ease-in-out;
}

.content-card:hover .content-card__image {
    transform: scale(1.05);
}

/* Button Transitions */
.btn,
button,
[role="button"] {
    transition: background-color 200ms ease-in-out, 
                color 200ms ease-in-out, 
                border-color 200ms ease-in-out,
                transform 200ms ease-in-out,
                box-shadow 200ms ease-in-out;
}

.btn:hover,
button:hover,
[role="button"]:hover {
    transform: translateY(-2px);
}

.btn:active,
button:active,
[role="button"]:active {
    transform: translateY(0);
}

/* Link Transitions */
a {
    transition: color 200ms ease-in-out, opacity 200ms ease-in-out;
}

/* Category Badge Transitions */
.content-card__category-badge {
    transition: transform 250ms ease-in-out, box-shadow 250ms ease-in-out;
}

.content-card__category-badge:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md, 0 4px 12px rgba(0, 0, 0, 0.1));
}

/* Author Link Transitions */
.content-card__author {
    transition: color 200ms ease-in-out, transform 200ms ease-in-out;
}

.content-card__author:hover {
    transform: translateX(2px);
}

/* Metadata Bar Transitions */
.metadata-bar__item {
    transition: color 200ms ease-in-out, transform 200ms ease-in-out;
}

.metadata-bar__item:hover {
    color: var(--color-primary, #3b82f6);
}

/* Filter Chip Transitions */
.filter-chip {
    transition: background-color 200ms ease-in-out, 
                transform 200ms ease-in-out,
                box-shadow 200ms ease-in-out;
}

.filter-chip:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm, 0 2px 8px rgba(0, 0, 0, 0.08));
}

.filter-chip__remove {
    transition: background-color 200ms ease-in-out, 
                color 200ms ease-in-out,
                transform 200ms ease-in-out;
}

.filter-chip__remove:hover {
    transform: scale(1.1);
}

/* Filter Tab Transitions */
.filter-tab {
    transition: background-color 250ms ease-in-out, 
                color 250ms ease-in-out,
                border-color 250ms ease-in-out;
}

/* Sort Dropdown Transitions */
.filter-sort,
select {
    transition: border-color 200ms ease-in-out, 
                box-shadow 200ms ease-in-out;
}

/* Sidebar Category Link Transitions */
.sidebar-category {
    transition: background-color 200ms ease-in-out, 
                transform 200ms ease-in-out,
                padding-left 200ms ease-in-out;
}

.sidebar-category:hover {
    transform: translateX(4px);
}

/* Tag Cloud Transitions */
.tag-cloud__tag {
    transition: background-color 200ms ease-in-out, 
                color 200ms ease-in-out,
                transform 200ms ease-in-out,
                box-shadow 200ms ease-in-out;
}

.tag-cloud__tag:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm, 0 2px 8px rgba(0, 0, 0, 0.08));
}

/* Progress Bar Transitions */
.progress-bar {
    transition: width 300ms ease-in-out;
}

.progress-bar__fill {
    transition: width 300ms ease-in-out, background-color 300ms ease-in-out;
}

/* Empty State Animation */
.articles-empty-state {
    animation: fadeInUp 0.6s ease-out backwards;
}

/* Loading Spinner Animation */
@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

.loading-spinner {
    animation: spin 1s linear infinite;
}

/* Pulse Animation for Loading States */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

.loading-pulse {
    animation: pulse 2s ease-in-out infinite;
}

/* Reduce Motion Preference */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .articles-grid .content-card {
        animation: none;
    }
    
    .article-hero,
    .category-hero,
    .articles-sidebar,
    .articles-sidebar-enhanced,
    .article-filters,
    .article-filters-advanced {
        animation: none;
    }
}

/* Smooth Scroll Behavior */
html {
    scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
}

/* Focus Transitions for Accessibility */
*:focus-visible {
    outline: 2px solid var(--color-primary, #3b82f6);
    outline-offset: 2px;
    transition: outline-offset 200ms ease-in-out;
}

/* Input and Textarea Transitions */
input,
textarea,
select {
    transition: border-color 200ms ease-in-out, 
                box-shadow 200ms ease-in-out,
                background-color 200ms ease-in-out;
}

/* Modal and Overlay Transitions */
.modal,
.overlay,
.bottom-sheet {
    transition: opacity 250ms ease-in-out, transform 250ms ease-in-out;
}

/* Tooltip Transitions */
.tooltip {
    transition: opacity 200ms ease-in-out, transform 200ms ease-in-out;
}