:root {
  /* Default Light Theme */
  --bg-color: #F8FAFC;
  --bg-secondary: #F1F5F9;
  --card-bg: #FFFFFF;
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --accent-color: #38BDF8;
  --accent-hover: #0284C7;
  --border-color: #E2E8F0;
  --header-bg: #FFFFFF;
  --danger: #EF4444;
}

[data-theme="light"] {
  --bg-color: #F8FAFC;
  --bg-secondary: #F1F5F9;
  --card-bg: #FFFFFF;
  --text-primary: #0F172A;
  --text-secondary: #475569;
  --accent-color: #38BDF8;
  --accent-hover: #0284C7;
  --border-color: #E2E8F0;
  --header-bg: #FFFFFF;
  --danger: #EF4444;
}

[data-theme="dark"] {
  /* Dark Theme */
  --bg-color: #0B1220;
  --bg-secondary: #0F172A;
  --card-bg: #1E293B;
  --text-primary: #F8FAFC;
  --text-secondary: #94A3B8;
  --accent-color: #38BDF8;
  --accent-hover: #7DD3FC;
  --border-color: #334155;
  --header-bg: #0B1220;
  --danger: #F87171;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 700;
  line-height: 1.2;
  color: var(--text-primary);
}

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--accent-color);
}

.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

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

ul {
  list-style: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1.5rem;
  font-weight: 600;
  border-radius: 4px;
  background-color: var(--accent-color);
  color: #0F172A;
  transition: background-color 0.2s, transform 0.2s;
  cursor: pointer;
  border: none;
}

.btn:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
  color: #0F172A;
}

.btn-outline {
  background-color: transparent;
  border: 1px solid var(--accent-color);
  color: var(--accent-color);
}

.btn-outline:hover {
  background-color: var(--accent-color);
  color: #0F172A;
}

/* Header — only the top-level site nav, not article headers */
body > header {
  position: sticky;
  top: 0;
  z-index: 9999;
  background-color: var(--header-bg);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  flex-direction: column;
}

.logo-main {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.logo-accent {
  color: var(--accent-color);
}

.tagline {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

nav ul {
  display: flex;
  gap: 1.5rem;
}

nav a {
  font-size: 0.9rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.search-bar {
  position: relative;
  display: none;
}

@media (min-width: 768px) {
  .search-bar {
    display: block;
  }
}

.search-bar input {
  padding: 0.5rem 1rem 0.5rem 2.5rem;
  border-radius: 20px;
  border: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  outline: none;
  width: 200px;
  transition: width 0.3s, border-color 0.3s;
}

.search-bar input:focus {
  width: 250px;
  border-color: var(--accent-color);
}

.search-icon {
  position: absolute;
  left: 0.8rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
}

.theme-toggle {
  background: none;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: color 0.2s;
}

.theme-toggle:hover {
  color: var(--accent-color);
}

.mobile-menu-btn {
  display: block;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

@media (min-width: 1024px) {
  .mobile-menu-btn {
    display: none;
  }
}

/* Progress bar */
.progress-container {
  width: 100%;
  height: 4px;
  background: transparent;
  position: fixed;
  top: 0;
  left: 0;
  z-index: 10001;
}

.progress-bar {
  height: 4px;
  background: var(--accent-color);
  width: 0%;
}

/* Layout Grid */
.main-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding: 2rem 0;
}

@media (min-width: 1024px) {
  .main-layout {
    grid-template-columns: 3fr 1fr;
    gap: 3rem;
  }
}

/* Category Badge */
.category-badge {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background-color: rgba(56, 189, 248, 0.1);
  color: var(--accent-color);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  border-radius: 4px;
  margin-bottom: 0.75rem;
}

/* Hero Section */
.hero {
  position: relative;
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 3rem;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
}

.hero img {
  width: 100%;
  height: 400px;
  object-fit: cover;
  transition: transform 0.5s ease;
}

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

.hero-overlay {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  background: linear-gradient(to top, rgba(11, 18, 32, 0.9) 0%, rgba(11, 18, 32, 0.5) 50%, transparent 100%);
  padding: 2rem;
  color: #F8FAFC;
}

.hero-title {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
  color: #F8FAFC;
}

@media (min-width: 768px) {
  .hero img {
    height: 500px;
  }
  .hero-title {
    font-size: 3rem;
  }
  .hero-overlay {
    padding: 3rem;
  }
}

/* Article Cards */
.grid-title {
  font-size: 1.5rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.grid-title::before {
  content: '';
  display: block;
  width: 12px;
  height: 12px;
  background-color: var(--accent-color);
  border-radius: 50%;
}

.article-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media (min-width: 768px) {
  .article-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.article-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  display: flex;
  flex-direction: column;
}

.article-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.article-card img {
  width: 100%;
  height: 200px;
  object-fit: cover;
}

.article-card-content {
  padding: 1.5rem;
  flex-grow: 1;
  display: flex;
  flex-direction: column;
}

.article-card-title {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  line-height: 1.4;
}

.article-card-desc {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
  flex-grow: 1;
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
}

/* Sidebar Elements */
.sidebar-widget {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.sidebar-title {
  font-size: 1.25rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--border-color);
  position: relative;
}

.sidebar-title::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 40px;
  height: 2px;
  background-color: var(--accent-color);
}

.trending-list li {
  margin-bottom: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.trending-list li:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.trending-link {
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.trending-number {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-secondary);
  opacity: 0.5;
}

.trending-title {
  font-weight: 600;
  font-size: 0.95rem;
  line-height: 1.4;
}

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

.category-item {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  color: var(--text-secondary);
  transition: color 0.2s;
}

.category-item:hover {
  color: var(--accent-color);
}

.newsletter-form {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.newsletter-form input {
  padding: 0.75rem 1rem;
  border-radius: 4px;
  border: 1px solid var(--border-color);
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
}

/* Article Page Layout */
article {
  background: transparent !important;
}

.article-header {
  margin-bottom: 2rem;
  text-align: center;
  max-width: 800px;
  margin: 0 auto 3rem auto;
}

.article-title {
  font-size: 2.5rem;
  margin: 1rem 0;
}

@media (min-width: 768px) {
  .article-title {
    font-size: 3.5rem;
  }
}

.author-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.author-info {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.author-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
}

.article-hero-img {
  width: 100%;
  height: auto;
  max-height: 600px;
  object-fit: cover;
  border-radius: 12px;
  margin-bottom: 3rem;
}

.article-content {
  max-width: 800px;
  margin: 0 auto;
  font-size: 1.125rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.article-content h2, .article-content h3 {
  margin-top: 2.5rem;
  margin-bottom: 1rem;
}

.article-content p {
  margin-bottom: 1.5rem;
}

.article-content ul, .article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.article-content li {
  margin-bottom: 0.5rem;
}

.article-content blockquote {
  border-left: 4px solid var(--accent-color);
  padding-left: 1rem;
  font-style: italic;
  margin-bottom: 1.5rem;
  background-color: var(--bg-secondary);
  padding: 1.5rem;
  border-radius: 0 8px 8px 0;
}

.related-articles {
  margin-top: 5rem;
  padding-top: 3rem;
  border-top: 1px solid var(--border-color);
}

/* Footer */
footer {
  background-color: var(--card-bg);
  border-top: 1px solid var(--border-color);
  padding: 4rem 0 2rem 0;
  margin-top: 4rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: repeat(4, 1fr);
  }
}

.footer-title {
  font-size: 1.1rem;
  margin-bottom: 1.5rem;
  color: var(--text-primary);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: var(--accent-color);
}

.copyright {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Utilities */
.hidden {
  display: none !important;
}

.mb-4 { margin-bottom: 1rem; }
.mt-4 { margin-top: 1rem; }

/* Responsive Nav */
.nav-links {
  display: none;
}

@media (min-width: 1024px) {
  .nav-links {
    display: flex;
  }
}

.mobile-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: var(--bg-color);
  z-index: 10000;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  transform: translateX(-100%);
  transition: transform 0.3s ease;
}

.mobile-nav.active {
  transform: translateX(0);
}

.mobile-nav-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 2rem;
  cursor: pointer;
}

.mobile-nav ul {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  text-align: center;
}

.mobile-nav a {
  font-size: 1.5rem;
  font-weight: 600;
}