/* ===== CSS RESET & BASE STYLES ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: #1a1a1a;
    background-color: #fafafa;
    overflow-x: hidden;
}

/* ===== DESIGN SYSTEM VARIABLES ===== */
:root {
    /* Colors */
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --accent-color: #f59e0b;
    --text-primary: #1a1a1a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --background: #fafafa;
    --surface: #ffffff;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-hero: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-card: linear-gradient(145deg, #ffffff 0%, #f8fafc 100%);
    
    /* Spacing */
    --container-max-width: 1200px;
    --container-padding: 1rem;
    --section-padding: 4rem 0;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease-out;
    --transition-normal: 0.3s ease-out;
    --transition-slow: 0.5s ease-out;
}

/* ===== UTILITY CLASSES ===== */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ===== HEADER STYLES ===== */
.header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-light);
    transition: all var(--transition-normal);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
}

.nav-list {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    position: relative;
    transition: color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -0.5rem;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width var(--transition-normal);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* ===== HERO SECTION ===== */
.hero {
    background: var(--gradient-hero);
    color: white;
    text-align: center;
    padding: 6rem 0 4rem;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="0.5" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 600px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
    animation: fadeInUp 1s ease-out;
}

.hero-subtitle {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 2rem;
    animation: fadeInUp 1s ease-out 0.2s both;
}

/* ===== MAIN CONTENT ===== */
.main {
    padding: var(--section-padding);
}

.articles-section {
    max-width: 100%;
}

/* ===== ARTICLES GRID ===== */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.article-card {
    background: var(--surface);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-normal);
    position: relative;
    animation: fadeInUp 0.6s ease-out;
}

.article-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.article-image-container {
    position: relative;
    height: 240px;
    overflow: hidden;
}

.article-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.article-card:hover .article-image {
    transform: scale(1.05);
}

.article-category {
    position: absolute;
    top: 1rem;
    left: 1rem;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-weight: 600;
    backdrop-filter: blur(10px);
}

.article-content {
    padding: 1.5rem;
}

.article-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    line-height: 1.4;
    color: var(--text-primary);
}

.article-excerpt {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.article-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.article-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: all var(--transition-fast);
}

.article-link:hover {
    color: var(--primary-hover);
    gap: 0.75rem;
}

.link-arrow {
    width: 1rem;
    height: 1rem;
    transition: transform var(--transition-fast);
}

.article-link:hover .link-arrow {
    transform: translateX(2px);
}

/* ===== LOADING STATE ===== */
.loading-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    padding: 2rem;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
}

.loading-state.active {
    opacity: 1;
    visibility: visible;
}

.loading-spinner {
    position: relative;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid var(--border);
    border-top: 3px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loading-text {
    color: var(--text-secondary);
    font-weight: 500;
}

/* ===== LOAD MORE BUTTON ===== */
.load-more-container {
    display: flex;
    justify-content: center;
    margin: 2rem 0;
}

.load-more-btn {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--gradient-primary);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--radius-lg);
    font-size: 3rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
}

.load-more-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.load-more-btn:active {
    transform: translateY(0);
}

.load-more-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.btn-text {
    position: relative;
    z-index: 2;
}

/* ===== ARROW LOOP ANIMATION ===== */
.arrow-loop {
    position: relative;
    width: 30px;
    height: 20px;
}

.arrow-icon {
    width: 24px;
    height: 24px;
    position: absolute;
    top: 0;
    left: 0;
    animation: arrowLoop 2s ease-in-out infinite;
}

@keyframes arrowLoop {
    0% {
        transform: translateX(0) rotate(0deg);
        opacity: 1;
    }
    25% {
        transform: translateX(10px) rotate(0deg);
        opacity: 0.7;
    }
    50% {
        transform: translateX(20px) rotate(360deg);
        opacity: 0;
    }
    51% {
        transform: translateX(-20px) rotate(360deg);
        opacity: 0;
    }
    75% {
        transform: translateX(-10px) rotate(360deg);
        opacity: 0.7;
    }
    100% {
        transform: translateX(0) rotate(360deg);
        opacity: 1;
    }
}

/* ===== END MESSAGE ===== */
.end-message {
    text-align: center;
    padding: 2rem;
    color: var(--text-secondary);
    font-weight: 500;
    background: var(--surface);
    border-radius: var(--radius-lg);
    border: 2px dashed var(--border);
}

/* ===== FOOTER ===== */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 2rem 0;
    margin-top: 4rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-link {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-link:hover {
    color: white;
}

/* ===== ANIMATIONS ===== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 768px) {
    :root {
        --container-padding: 1rem;
    }
    
    .header-content {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-list {
        gap: 1rem;
    }
    
    .hero {
        padding: 4rem 0 3rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .articles-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .article-card {
        margin: 0;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .load-more-btn {
        padding: 0.875rem 1.5rem;
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    .article-image-container {
        height: 200px;
    }
    
    .article-content {
        padding: 1rem;
    }
    
    .hero {
        padding: 3rem 0 2rem;
    }
    
    .nav-list {
        flex-direction: column;
        text-align: center;
        gap: 0.5rem;
    }
}

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    .arrow-icon {
        animation: none;
    }
    
    .spinner {
        animation: none;
    }
}

/* ===== FOCUS STYLES ===== */
.load-more-btn:focus-visible,
.nav-link:focus-visible,
.article-link:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* ===== PRINT STYLES ===== */
@media print {
    .header,
    .load-more-container,
    .loading-state,
    .footer {
        display: none;
    }
    
    .article-card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid var(--border);
    }
}