/* CSS Variables for Light and Dark Themes */
:root {
  /* Light Theme Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  --accent-primary: #3b82f6;
  --accent-secondary: #1d4ed8;
  --border-color: #e2e8f0;
  --shadow-light: rgba(0, 0, 0, 0.1);
  --shadow-medium: rgba(0, 0, 0, 0.15);
  --shadow-heavy: rgba(0, 0, 0, 0.25);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Transitions */
  --transition-fast: 0.15s ease-in-out;
  --transition-normal: 0.3s ease-in-out;
  --transition-slow: 0.5s ease-in-out;
}

/* Dark Theme Colors */
[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --accent-primary: #60a5fa;
  --accent-secondary: #3b82f6;
  --border-color: #334155;
  --shadow-light: rgba(0, 0, 0, 0.3);
  --shadow-medium: rgba(0, 0, 0, 0.4);
  --shadow-heavy: rgba(0, 0, 0, 0.6);
}

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

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 { font-size: var(--font-size-4xl); }
h2 { font-size: var(--font-size-3xl); }
h3 { font-size: var(--font-size-2xl); }
h4 { font-size: var(--font-size-xl); }
h5 { font-size: var(--font-size-lg); }
h6 { font-size: var(--font-size-base); }

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

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

/* Header Styles */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background-color: var(--bg-primary);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  z-index: 1000;
  transition: all var(--transition-normal);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.brand-name {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--text-primary);
  margin: 0;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
}

.nav-link {
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--accent-primary);
  transition: width var(--transition-fast);
}

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

.theme-toggle {
  background: none;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm);
  cursor: pointer;
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  transform: scale(1.05);
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 4px;
}

.mobile-menu-toggle span {
  width: 25px;
  height: 3px;
  background-color: var(--text-primary);
  transition: all var(--transition-fast);
}

/* Hero Section */
.hero {
  padding: 120px 0 var(--spacing-3xl);
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
}

.hero-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.hero-content {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--spacing-3xl);
  align-items: center;
}

.hero-image {
  display: flex;
  justify-content: center;
}

.author-photo {
  width: 300px;
  height: 300px;
  border-radius: 50%;
  object-fit: cover;
  border: 6px solid var(--bg-primary);
  box-shadow: 0 20px 40px var(--shadow-medium);
  transition: transform var(--transition-slow);
}

.author-photo:hover {
  transform: scale(1.05);
}

.hero-title {
  font-size: var(--font-size-5xl);
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
  line-height: 1.7;
}

.cta-button {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  color: white;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-lg);
  font-weight: 600;
  transition: all var(--transition-fast);
  box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.cta-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(59, 130, 246, 0.4);
  color: white;
}

/* Articles Section */
.articles {
  padding: var(--spacing-3xl) 0;
  background-color: var(--bg-primary);
}

.articles-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
  font-size: var(--font-size-4xl);
  font-weight: 700;
}

.articles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--spacing-xl);
}

.article-card {
  background-color: var(--bg-secondary);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: 0 4px 20px var(--shadow-light);
  transition: all var(--transition-normal);
  border: 1px solid var(--border-color);
}

.article-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 12px 40px var(--shadow-medium);
}

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

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

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

.article-content {
  padding: var(--spacing-xl);
}

.article-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.article-date {
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.article-category {
  background-color: var(--accent-primary);
  color: white;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.article-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
  line-height: 1.3;
}

.article-excerpt {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.6;
}

.article-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  color: var(--accent-primary);
  font-weight: 600;
  transition: all var(--transition-fast);
}

.article-link:hover {
  gap: var(--spacing-md);
}

/* About Section */
.about {
  padding: var(--spacing-3xl) 0;
  background-color: var(--bg-secondary);
}

.about-container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
  text-align: center;
}

.about-content {
  font-size: var(--font-size-lg);
  line-height: 1.8;
}

.about-content p {
  margin-bottom: var(--spacing-xl);
}

/* Footer */
.footer {
  background-color: var(--bg-tertiary);
  padding: var(--spacing-3xl) 0 var(--spacing-xl);
  border-top: 1px solid var(--border-color);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.footer-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-3xl);
  margin-bottom: var(--spacing-xl);
}

.footer-brand h3 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--spacing-sm);
}

.footer-brand p {
  color: var(--text-muted);
}

.footer-links {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
}

.footer-section h4 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
}

.footer-section ul {
  list-style: none;
}

.footer-section ul li {
  margin-bottom: var(--spacing-sm);
}

.footer-section ul li a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-section ul li a:hover {
  color: var(--accent-primary);
}

.social-links {
  display: flex;
  gap: var(--spacing-md);
}

.social-links a {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background-color: var(--bg-primary);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
}

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

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border-color);
}

.footer-bottom p {
  color: var(--text-muted);
  margin: 0;
}

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

@keyframes fadeInLeft {
  from {
    opacity: 0;
    transform: translateX(-30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes fadeInRight {
  from {
    opacity: 0;
    transform: translateX(30px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

.animate-text {
  animation: fadeInLeft 0.8s ease-out;
}

.animate-text-delay {
  animation: fadeInLeft 0.8s ease-out 0.2s both;
}

.animate-on-scroll {
  opacity: 0;
  transform: translateY(30px);
  transition: all 0.6s ease-out;
}

.animate-on-scroll.animate {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --font-size-4xl: 2rem;
    --font-size-5xl: 2.5rem;
  }

  .nav-menu {
    display: none;
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .hero {
    padding: 100px 0 var(--spacing-2xl);
    min-height: auto;
  }

  .hero-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-2xl);
    text-align: center;
  }

  .author-photo {
    width: 250px;
    height: 250px;
  }

  .hero-title {
    font-size: var(--font-size-4xl);
  }

  .articles-grid {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }

  .footer-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
    text-align: center;
  }

  .footer-links {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }

  .social-links {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .nav-container {
    padding: 0 var(--spacing-md);
  }

  .hero-container,
  .articles-container,
  .about-container,
  .footer-container {
    padding: 0 var(--spacing-md);
  }

  .author-photo {
    width: 200px;
    height: 200px;
  }

  .hero-title {
    font-size: var(--font-size-3xl);
  }

  .section-title {
    font-size: var(--font-size-3xl);
  }

  .articles-grid {
    grid-template-columns: 1fr;
  }

  .article-card {
    margin: 0 var(--spacing-sm);
  }
}

/* Smooth scrolling for all browsers */
html {
  scroll-behavior: smooth;
}

/* Focus styles for accessibility */
*:focus {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* Print styles */
@media print {
  .header,
  .theme-toggle,
  .mobile-menu-toggle {
    display: none;
  }
  
  .hero {
    padding-top: 0;
  }
  
  body {
    background: white;
    color: black;
  }
}