/* CSS Custom Properties for Theme Management */
:root {
  /* Light Theme Colors */
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e9ecef;
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #adb5bd;
  --accent-primary: #0d6efd;
  --accent-secondary: #6f42c1;
  --border-color: #dee2e6;
  --shadow: rgba(0, 0, 0, 0.1);
  --shadow-hover: rgba(0, 0, 0, 0.15);
  
  /* 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;
  
  /* 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: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.3s ease;
  --transition-slow: 0.5s ease;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #121212;
  --bg-secondary: #1e1e1e;
  --bg-tertiary: #2d2d2d;
  --text-primary: #ffffff;
  --text-secondary: #bb86fc;
  --text-muted: #8e8e93;
  --accent-primary: #bb86fc;
  --accent-secondary: #03dac6;
  --border-color: #333333;
  --shadow: rgba(0, 0, 0, 0.3);
  --shadow-hover: rgba(0, 0, 0, 0.4);
}

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

html {
  scroll-behavior: smooth;
}

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

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  left: -999px;
  top: auto;
  width: 1px;
  height: 1px;
  overflow: hidden;
  background: var(--accent-primary);
  color: var(--bg-primary);
  padding: var(--spacing-sm) var(--spacing-md);
  text-decoration: none;
  border-radius: var(--radius-sm);
  z-index: 1000;
}

.skip-link:focus {
  position: static;
  width: auto;
  height: auto;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* Header */
.header {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.9);
  transition: transform var(--transition-normal), opacity var(--transition-normal);
}

[data-theme="dark"] .header {
  background-color: rgba(18, 18, 18, 0.9);
}

/* Auto-hide header modifier */
.header.header--hidden {
  transform: translateY(-100%);
  opacity: 0.98;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) 0;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.logo a {
  font-size: var(--font-size-xl);
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* Navigation */
.nav-list {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
  flex-wrap: wrap;
}

.nav-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-fast);
  padding: var(--spacing-sm) 0;
}

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

/* Header Controls */
.header-controls {
  display: flex;
  gap: var(--spacing-sm);
  align-items: center;
}

.theme-toggle,
.reading-mode-toggle {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
  font-size: var(--font-size-lg);
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle:hover,
.reading-mode-toggle:hover {
  background: var(--bg-tertiary);
  transform: translateY(-1px);
}

/* Main Content */
.main {
  min-height: calc(100vh - 200px);
  padding: var(--spacing-2xl) 0;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: var(--spacing-3xl) 0;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  border-radius: var(--radius-xl);
  margin-bottom: var(--spacing-3xl);
}

.hero-title {
  font-size: var(--font-size-4xl);
  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-xl);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.cta-button {
  display: inline-block;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-lg);
  text-decoration: none;
  font-weight: 600;
  transition: all var(--transition-fast);
  box-shadow: 0 4px 6px var(--shadow);
  border: 2px solid transparent;
}

.cta-button.primary {
  background: var(--accent-primary);
  color: var(--bg-primary);
}

.cta-button.secondary {
  background: transparent;
  color: var(--accent-primary);
  border-color: var(--accent-primary);
}

.cta-button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px var(--shadow-hover);
}

.cta-button.secondary:hover {
  background: var(--accent-primary);
  color: var(--bg-primary);
}

.hero-actions {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  flex-wrap: wrap;
  margin-top: var(--spacing-xl);
}

/* Featured Post */
.featured-post {
  margin-bottom: var(--spacing-3xl);
}

.post-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: 0 2px 4px var(--shadow);
  transition: all var(--transition-normal);
}

.post-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 16px var(--shadow-hover);
}

.post-meta {
  display: flex;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-md);
  font-size: var(--font-size-sm);
  color: var(--text-muted);
}

.post-title {
  font-size: var(--font-size-2xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
}

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

.post-title a:hover {
  color: var(--accent-primary);
}

.post-excerpt {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  line-height: 1.7;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.tag {
  background: var(--bg-secondary);
  color: var(--text-secondary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius-sm);
  font-size: var(--font-size-xs);
  font-weight: 500;
}

.read-more {
  color: var(--accent-primary);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--transition-fast);
}

.read-more:hover {
  color: var(--accent-secondary);
}

/* About Section */
.about {
  background: var(--bg-secondary);
  padding: var(--spacing-2xl);
  border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-3xl);
}

.about h2 {
  font-size: var(--font-size-3xl);
  margin-bottom: var(--spacing-lg);
  color: var(--text-primary);
}

.about p {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-md);
  line-height: 1.7;
}

/* Post content paragraph styling */
.post-content p {
  margin-bottom: var(--spacing-lg);
  line-height: 1.8;
  color: var(--text-primary);
}

/* Post section spacing */
.post-section {
  margin-bottom: var(--spacing-2xl);
}

.post-section h2 {
  margin-bottom: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.post-section h3 {
  margin-bottom: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.post-section h4 {
  margin-bottom: var(--spacing-sm);
  margin-top: var(--spacing-md);
}

/* List styling improvements */
.post-content ul,
.post-content ol {
  margin-bottom: var(--spacing-lg);
  padding-left: var(--spacing-xl);
}

.post-content li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.7;
}

.post-content ul li {
  list-style-type: disc;
}

.post-content ol li {
  list-style-type: decimal;
}

/* Abstract section styling */
.abstract {
  background: var(--bg-secondary);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  border-left: 4px solid var(--accent-primary);
  margin-bottom: var(--spacing-xl);
}

.abstract h2 {
  margin-top: 0;
  color: var(--accent-primary);
}

.abstract p {
  font-style: italic;
  font-size: 1.1rem;
  line-height: 1.8;
}

/* Image styling */
.image-container {
  margin: var(--spacing-xl) 0;
  text-align: center;
}

.content-image {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 24px var(--shadow);
  transition: transform var(--transition-normal);
  margin-bottom: var(--spacing-md);
}

.content-image:hover {
  transform: scale(1.02);
}

.image-caption {
  font-style: italic;
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
  margin-top: var(--spacing-sm);
  line-height: 1.6;
}

/* Image gallery for multiple images */
.image-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
}

.image-gallery .image-container {
  margin: 0;
}

/* Responsive image adjustments */
@media (max-width: 768px) {
  .image-gallery {
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
  }
  
  .content-image {
    border-radius: var(--radius-md);
  }
}

/* Link styling improvements */
.post-content a {
  color: var(--accent-primary);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: all var(--transition-fast);
  position: relative;
  display: inline-block;
}

.post-content a:hover {
  color: var(--accent-secondary);
  border-bottom-color: var(--accent-primary);
  transform: translateY(-1px);
}

/* External link styling with icons */
.post-content a[target="_blank"]:after {
  content: "↗";
  font-size: 0.8em;
  margin-left: 0.25em;
  opacity: 0.7;
  transition: opacity var(--transition-fast);
}

.post-content a[target="_blank"]:hover:after {
  opacity: 1;
}

/* Reference links styling */
.post-content .references a {
  color: var(--accent-primary);
  text-decoration: none;
  border-bottom: 1px solid var(--border-color);
  transition: all var(--transition-fast);
}

.post-content .references a:hover {
  color: var(--accent-secondary);
  border-bottom-color: var(--accent-primary);
  background: var(--bg-secondary);
  padding: 0.125rem 0.25rem;
  border-radius: var(--radius-sm);
}

/* Footer */
.footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-2xl) 0;
  text-align: center;
  color: var(--text-secondary);
}

.footer p {
  margin-bottom: var(--spacing-sm);
}

/* Share buttons styling */
.post-share {
  margin-top: var(--spacing-xl);
  padding: var(--spacing-lg);
  background: var(--bg-secondary);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-color);
}

.post-share p {
  margin-bottom: var(--spacing-md);
  font-weight: 600;
  color: var(--text-primary);
}

.share-buttons {
  display: flex;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.share-button {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 500;
  font-size: var(--font-size-sm);
  transition: all var(--transition-fast);
  cursor: pointer;
  box-shadow: 0 2px 4px var(--shadow);
}

.share-button:hover {
  background: var(--accent-primary);
  color: var(--bg-primary);
  border-color: var(--accent-primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 8px var(--shadow-hover);
}

.share-button:active {
  transform: translateY(0);
  box-shadow: 0 2px 4px var(--shadow);
}

/* Share button icons - removed for cleaner look */

/* Mobile responsive share buttons */
@media (max-width: 768px) {
  .share-buttons {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .share-button {
    justify-content: center;
    padding: var(--spacing-md);
    font-size: var(--font-size-base);
  }
}

/* Responsive Design - Mobile First */
@media (min-width: 768px) {
  .container {
    padding: 0 var(--spacing-xl);
  }
  
  .header-content {
    flex-wrap: nowrap;
  }
  
  .hero-title {
    font-size: 3.5rem;
  }
  
  .hero-subtitle {
    font-size: var(--font-size-2xl);
  }
  
  .nav-list {
    gap: var(--spacing-xl);
  }
}

@media (min-width: 1024px) {
  .hero {
    padding: var(--spacing-3xl) var(--spacing-2xl);
  }
  
  .hero-title {
    font-size: 4rem;
  }
  
  .post-card {
    padding: var(--spacing-2xl);
  }
  
  .about {
    padding: var(--spacing-3xl);
  }
}

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

/* Smooth transitions for theme switching */
* {
  transition: background-color var(--transition-normal), 
              color var(--transition-normal), 
              border-color var(--transition-normal);
}

/* Print styles */
@media print {
  .header-controls,
  .skip-link {
    display: none;
  }
  
  .hero {
    background: none;
    border: 1px solid var(--border-color);
  }
  
  .post-card {
    box-shadow: none;
    border: 1px solid var(--border-color);
  }
}

/* Google Translate Widget Styling */
.translate-widget {
  margin-right: var(--spacing-md);
  display: inline-block;
  vertical-align: middle;
  min-width: 120px;
  position: relative;
}

/* Google Translate Dropdown Styling */
.goog-te-gadget {
  font-family: var(--font-family) !important;
  font-size: var(--font-size-sm) !important;
}

.goog-te-gadget-simple {
  background: var(--bg-secondary) !important;
  border: 1px solid var(--border-color) !important;
  border-radius: var(--radius-md) !important;
  padding: var(--spacing-sm) var(--spacing-md) !important;
  color: var(--text-primary) !important;
  transition: all var(--transition-fast) !important;
  cursor: pointer !important;
  display: inline-block !important;
  text-decoration: none !important;
  font-size: var(--font-size-sm) !important;
  line-height: 1.4 !important;
  min-width: 100px !important;
  text-align: left !important;
}

.goog-te-gadget-simple:hover {
  background: var(--bg-tertiary) !important;
  border-color: var(--accent-primary) !important;
  transform: translateY(-1px) !important;
  box-shadow: 0 2px 8px var(--shadow) !important;
}

.goog-te-gadget-simple:focus {
  outline: 2px solid var(--accent-primary) !important;
  outline-offset: 2px !important;
}

/* Google Translate Text */
.goog-te-gadget-simple .goog-te-menu-value {
  color: var(--text-primary) !important;
  font-size: var(--font-size-sm) !important;
  font-weight: 500 !important;
}

.goog-te-gadget-simple .goog-te-menu-value span:first-child {
  color: var(--text-primary) !important;
}

/* Google Translate Dropdown Menu */
.goog-te-menu2 {
  background: var(--bg-primary) !important;
  border: 1px solid var(--border-color) !important;
  border-radius: var(--radius-lg) !important;
  box-shadow: 0 8px 24px var(--shadow) !important;
  max-height: 300px !important;
  overflow-y: auto !important;
  z-index: 1000 !important;
  min-width: 250px !important;
  width: auto !important;
  max-width: 400px !important;
}

.goog-te-menu2-item {
  color: var(--text-primary) !important;
  padding: var(--spacing-sm) var(--spacing-md) !important;
  font-size: var(--font-size-sm) !important;
  transition: background-color var(--transition-fast) !important;
  white-space: nowrap !important;
  min-width: 200px !important;
}

.goog-te-menu2-item:hover {
  background: var(--bg-secondary) !important;
  color: var(--accent-primary) !important;
}

.goog-te-menu2-item-selected {
  background: var(--accent-primary) !important;
  color: var(--bg-primary) !important;
}

/* Hide Google Translate Branding */
.goog-te-gadget .goog-te-combo {
  margin: 0 !important;
}

/* Responsive Design for Translate Widget */
@media (max-width: 768px) {
  .translate-widget {
    margin-right: var(--spacing-sm);
  }
  
  .goog-te-gadget-simple {
    padding: var(--spacing-xs) var(--spacing-sm) !important;
    font-size: var(--font-size-xs) !important;
  }
  
  .goog-te-gadget-simple .goog-te-menu-value {
    font-size: var(--font-size-xs) !important;
  }
}

@media (max-width: 480px) {
  .header-controls {
    flex-wrap: wrap;
    gap: var(--spacing-sm);
  }
  
  .translate-widget {
    order: -1;
    width: 100%;
    margin-right: 0;
    margin-bottom: var(--spacing-sm);
  }
  
  .goog-te-gadget-simple {
    width: 100%;
    text-align: center;
  }
}

/* Translate Fallback Styling for Localhost */
.translate-fallback {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-xs);
}

.translate-fallback-btn {
  background: var(--accent-primary);
  color: var(--bg-primary);
  border: none;
  border-radius: var(--radius-md);
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--font-size-sm);
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  text-decoration: none;
  font-family: var(--font-family);
}

.translate-fallback-btn:hover {
  background: var(--accent-secondary);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px var(--shadow);
}

.translate-fallback-btn:focus {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

.translate-fallback-text {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  margin: 0;
  text-align: center;
  line-height: 1.3;
}

/* Dark theme for fallback */
[data-theme="dark"] .translate-fallback-btn {
  background: var(--accent-primary);
  color: var(--bg-primary);
}

[data-theme="dark"] .translate-fallback-btn:hover {
  background: var(--accent-secondary);
}

[data-theme="dark"] .translate-fallback-text {
  color: var(--text-secondary);
}

/* Mobile responsive for fallback */
@media (max-width: 480px) {
  .translate-fallback {
    width: 100%;
  }
  
  .translate-fallback-btn {
    width: 100%;
    justify-content: center;
  }
  
  .translate-fallback-text {
    font-size: 0.7rem;
  }
}