/* CSS Custom Properties */
:root {
  --primary-color: #2c3e50;
  --secondary-color: #e74c3c;
  --accent-color: #f39c12;
  --text-primary: #2c3e50;
  --text-secondary: #7f8c8d;
  --text-light: #95a5a6;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #ecf0f1;
  --border-color: #e9ecef;
  --shadow-light: 0 2px 4px rgba(0, 0, 0, 0.1);
  --shadow-medium: 0 4px 8px rgba(0, 0, 0, 0.12);
  --shadow-heavy: 0 8px 24px rgba(0, 0, 0, 0.15);
  --border-radius: 8px;
  --border-radius-lg: 12px;
  --transition: all 0.3s ease;
  --container-max-width: 1200px;
  --sidebar-width: 300px;
}

/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition);
}

ul {
  list-style: none;
}

button {
  border: none;
  background: none;
  cursor: pointer;
  font-family: inherit;
  transition: var(--transition);
}

/* Container */
.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 1rem;
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  transition: var(--transition);
}

.navbar {
  padding: 1rem 0;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.nav-brand h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
}

.nav-menu {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  gap: 2rem;
}

.nav-link {
  font-weight: 500;
  color: var(--text-secondary);
  position: relative;
  padding: 0.5rem 0;
}

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

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--secondary-color);
  border-radius: 2px;
}

.nav-search {
  display: flex;
  align-items: center;
  position: relative;
}

.search-input {
  padding: 0.5rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background: var(--bg-secondary);
  font-size: 0.9rem;
  width: 200px;
  transition: var(--transition);
}

.search-input:focus {
  outline: none;
  border-color: var(--secondary-color);
  box-shadow: 0 0 0 3px rgba(231, 76, 60, 0.1);
}

.search-btn {
  position: absolute;
  right: 0.5rem;
  padding: 0.25rem;
  color: var(--text-secondary);
}

.search-btn:hover {
  color: var(--secondary-color);
}

.nav-toggle {
  display: none;
  padding: 0.5rem;
  color: var(--text-primary);
}

/* Hero Section */
.hero {
  margin-top: 80px;
  padding: 3rem 0;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
}

.hero-content {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 1rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.hero-category {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: var(--secondary-color);
  color: white;
  font-size: 0.8rem;
  font-weight: 500;
  border-radius: var(--border-radius);
  margin-bottom: 1rem;
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  color: var(--primary-color);
}

.hero-description {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
  line-height: 1.6;
}

.hero-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  background: var(--secondary-color);
  color: white;
  font-weight: 500;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.hero-btn:hover {
  background: #c0392b;
  transform: translateY(-2px);
  box-shadow: var(--shadow-medium);
}

.hero-image {
  position: relative;
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-heavy);
}

.hero-image img {
  width: 100%;
  height: 400px;
  object-fit: cover;
  transition: var(--transition);
}

.hero-image:hover img {
  transform: scale(1.05);
}

/* Content Section */
.content-section {
  padding: 4rem 0;
}

.content-grid {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: 3rem;
}

/* Articles Grid */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  flex-wrap: wrap;
  gap: 1rem;
}

.section-header h3 {
  font-size: 1.8rem;
  font-weight: 600;
  color: var(--primary-color);
}

.filter-tabs {
  display: flex;
  gap: 0.5rem;
  background: var(--bg-secondary);
  padding: 0.25rem;
  border-radius: var(--border-radius);
}

.filter-tab {
  padding: 0.5rem 1rem;
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: var(--transition);
}

.filter-tab:hover,
.filter-tab.active {
  background: var(--secondary-color);
  color: white;
}

.articles-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-bottom: 3rem;
}

/* Article Cards */
.article-card {
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-light);
  transition: var(--transition);
  opacity: 0;
  transform: translateY(20px);
  animation: fadeInUp 0.6s ease forwards;
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-heavy);
}

.article-image {
  position: relative;
  height: 200px;
  overflow: hidden;
}

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

.article-card:hover .article-image img {
  transform: scale(1.1);
}

.article-category {
  position: absolute;
  top: 1rem;
  left: 1rem;
  background: var(--accent-color);
  color: white;
  padding: 0.25rem 0.75rem;
  border-radius: var(--border-radius);
  font-size: 0.8rem;
  font-weight: 500;
}

.article-content {
  padding: 1.5rem;
}

.article-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--primary-color);
  line-height: 1.3;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-excerpt {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1rem;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--text-light);
}

.read-time {
  font-weight: 500;
}

/* Load More Button */
.load-more-container {
  text-align: center;
}

.load-more-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 2rem;
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-weight: 500;
  border-radius: var(--border-radius);
  border: 2px solid var(--border-color);
  transition: var(--transition);
}

.load-more-btn:hover {
  background: var(--secondary-color);
  color: white;
  border-color: var(--secondary-color);
}

/* Sidebar */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.widget {
  background: var(--bg-primary);
  border-radius: var(--border-radius-lg);
  padding: 1.5rem;
  box-shadow: var(--shadow-light);
}

.widget-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--primary-color);
  padding-bottom: 0.5rem;
  border-bottom: 2px solid var(--bg-secondary);
}

/* Recent Posts */
.recent-posts {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.recent-post {
  display: flex;
  gap: 0.75rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--bg-secondary);
}

.recent-post:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.recent-post-image {
  flex-shrink: 0;
  width: 60px;
  height: 60px;
  border-radius: var(--border-radius);
  overflow: hidden;
}

.recent-post-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.recent-post-content h5 {
  font-size: 0.9rem;
  font-weight: 500;
  margin-bottom: 0.25rem;
  color: var(--primary-color);
  line-height: 1.3;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.recent-post-date {
  font-size: 0.8rem;
  color: var(--text-light);
}

/* Categories */
.category-list {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.category-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.category-list a {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
  padding: 0.5rem 0;
  color: var(--text-secondary);
  transition: var(--transition);
}

.category-list a:hover {
  color: var(--secondary-color);
}

.category-list span {
  background: var(--bg-secondary);
  color: var(--text-light);
  padding: 0.2rem 0.5rem;
  border-radius: var(--border-radius);
  font-size: 0.8rem;
}

/* Newsletter */
.newsletter-widget {
  background: linear-gradient(135deg, var(--secondary-color), #c0392b);
  color: white;
}

.newsletter-widget .widget-title {
  color: white;
  border-bottom-color: rgba(255, 255, 255, 0.2);
}

.newsletter-widget p {
  margin-bottom: 1rem;
  opacity: 0.9;
}

.newsletter-form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.newsletter-input {
  padding: 0.75rem;
  border: none;
  border-radius: var(--border-radius);
  font-size: 0.9rem;
}

.newsletter-input:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.3);
}

.newsletter-btn {
  padding: 0.75rem;
  background: white;
  color: var(--secondary-color);
  font-weight: 600;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.newsletter-btn:hover {
  background: var(--bg-secondary);
}

/* Footer */
.footer {
  background: var(--primary-color);
  color: white;
  padding: 3rem 0 1rem;
  margin-top: 4rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-col h5 {
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.footer-col h6 {
  font-size: 1rem;
  font-weight: 500;
  margin-bottom: 1rem;
  color: #bdc3c7;
}

.footer-col p {
  margin-bottom: 1.5rem;
  color: #bdc3c7;
  line-height: 1.6;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-col a {
  color: #bdc3c7;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.footer-col a:hover {
  color: white;
}

.social-links {
  display: flex;
  gap: 1rem;
}

.social-links a {
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.social-links a:hover {
  background: var(--secondary-color);
  transform: translateY(-2px);
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: #bdc3c7;
}

/* Back to Top */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 50px;
  height: 50px;
  background: var(--secondary-color);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-heavy);
  opacity: 0;
  visibility: hidden;
  transform: translateY(20px);
  transition: var(--transition);
  z-index: 1000;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  background: #c0392b;
  transform: translateY(-2px);
}

/* Loading States */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(255, 255, 255, 0.9);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
}

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

.loading-spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--bg-secondary);
  border-top: 4px solid var(--secondary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

/* Lazy Loading */
.lazy-image {
  opacity: 0;
  transition: opacity 0.3s ease;
  filter: blur(5px);
}

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

.lazy-image.loading {
  background: linear-gradient(90deg, var(--bg-secondary) 25%, var(--bg-tertiary) 50%, var(--bg-secondary) 75%);
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

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

/* Responsive Design */
@media (max-width: 1024px) {
  .content-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  .hero-content {
    grid-template-columns: 1fr;
    gap: 2rem;
    text-align: center;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .articles-container {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
  }
}

@media (max-width: 768px) {
  .nav-menu {
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
  }
  
  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }
  
  .nav-list {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }
  
  .nav-search {
    width: 150px;
  }
  
  .search-input {
    width: 100%;
  }
  
  .nav-toggle {
    display: block;
  }
  
  .hero {
    padding: 2rem 0;
  }
  
  .hero-title {
    font-size: 1.8rem;
  }
  
  .hero-description {
    font-size: 1rem;
  }
  
  .section-header {
    flex-direction: column;
    align-items: stretch;
  }
  
  .filter-tabs {
    justify-content: center;
    flex-wrap: wrap;
  }
  
  .articles-container {
    grid-template-columns: 1fr;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
    text-align: center;
  }
  
  .back-to-top {
    bottom: 1rem;
    right: 1rem;
    width: 45px;
    height: 45px;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 0.5rem;
  }
  
  .hero-content {
    padding: 0 0.5rem;
  }
  
  .hero-title {
    font-size: 1.5rem;
  }
  
  .article-content {
    padding: 1rem;
  }
  
  .widget {
    padding: 1rem;
  }
  
  .footer {
    padding: 2rem 0 1rem;
  }
}

/* Print Styles */
@media print {
  .header,
  .nav-menu,
  .sidebar,
  .footer,
  .back-to-top,
  .loading-overlay {
    display: none !important;
  }
  
  .main {
    margin-top: 0 !important;
  }
  
  .article-card {
    break-inside: avoid;
    box-shadow: none;
    border: 1px solid #ddd;
    margin-bottom: 1rem;
  }
}

/* Dark Mode Support */
@media (prefers-color-scheme: dark) {
  :root {
    --primary-color: #ecf0f1;
    --text-primary: #ecf0f1;
    --text-secondary: #bdc3c7;
    --text-light: #95a5a6;
    --bg-primary: #2c3e50;
    --bg-secondary: #34495e;
    --bg-tertiary: #3c5773;
    --border-color: #4a5f7a;
  }
  
  .header {
    background: rgba(44, 62, 80, 0.95);
  }
  
  .search-input {
    background: var(--bg-tertiary);
    color: var(--text-primary);
  }
  
  .article-card,
  .widget {
    background: var(--bg-secondary);
  }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}

/* Focus States */
.nav-link:focus,
.search-input:focus,
.search-btn:focus,
.hero-btn:focus,
.filter-tab:focus,
.load-more-btn:focus,
.newsletter-input:focus,
.newsletter-btn:focus,
.back-to-top:focus {
  outline: 2px solid var(--secondary-color);
  outline-offset: 2px;
}

/* High Contrast Mode */
@media (prefers-contrast: high) {
  :root {
    --shadow-light: 0 2px 4px rgba(0, 0, 0, 0.5);
    --shadow-medium: 0 4px 8px rgba(0, 0, 0, 0.5);
    --shadow-heavy: 0 8px 24px rgba(0, 0, 0, 0.5);
  }
  
  .article-card,
  .widget {
    border: 2px solid var(--border-color);
  }
}