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

/* CSS Custom Properties for Theme System */
: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: #8b5cf6;
  --border-light: #e2e8f0;
  --border-medium: #cbd5e1;
  --shadow-light: rgba(0, 0, 0, 0.05);
  --shadow-medium: rgba(0, 0, 0, 0.1);
  --shadow-heavy: rgba(0, 0, 0, 0.15);
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  
  /* Border radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;
}

/* Dark theme colors */
[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --accent-primary: #60a5fa;
  --accent-secondary: #a78bfa;
  --border-light: #334155;
  --border-medium: #475569;
  --shadow-light: rgba(0, 0, 0, 0.3);
  --shadow-medium: rgba(0, 0, 0, 0.4);
  --shadow-heavy: rgba(0, 0, 0, 0.5);
}

/* Auto theme detection */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --accent-primary: #60a5fa;
    --accent-secondary: #a78bfa;
    --border-light: #334155;
    --border-medium: #475569;
    --shadow-light: rgba(0, 0, 0, 0.3);
    --shadow-medium: rgba(0, 0, 0, 0.4);
    --shadow-heavy: rgba(0, 0, 0, 0.5);
  }
}

/* Base styles */
html {
  font-family: var(--font-sans);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: background-color var(--transition-normal), color var(--transition-normal);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
}

h1 {
  font-size: 2.5rem;
  margin-bottom: var(--space-lg);
}

h2 {
  font-size: 2rem;
  margin-bottom: var(--space-md);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--space-md);
}

h4 {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
}

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

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

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

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.main-content {
  flex: 1;
  padding: var(--space-xl) 0 var(--space-3xl);
}

/* Header Styles */
.site-header {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-light);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
  background-color: rgba(255, 255, 255, 0.8);
}

[data-theme="dark"] .site-header {
  background-color: rgba(15, 23, 42, 0.8);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 3.5rem;
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.brand-link {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-primary);
  font-weight: 600;
  font-size: 1.125rem;
}

.brand-logo {
  width: 1.75rem;
  height: 1.75rem;
  object-fit: contain;
}

.brand-section {
  color: var(--text-muted);
  font-weight: 400;
  font-size: 0.9rem;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

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

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

.header-controls {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: var(--space-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  width: 2.5rem;
  height: 2.5rem;
}

.theme-toggle:hover {
  background-color: var(--bg-secondary);
  border-color: var(--border-medium);
}

.theme-icon {
  width: 1.25rem;
  height: 1.25rem;
  color: var(--text-secondary);
}

.theme-icon-dark {
  display: none;
}

[data-theme="dark"] .theme-icon-light {
  display: none;
}

[data-theme="dark"] .theme-icon-dark {
  display: block;
}

/* Blog Post Styles */
.blog-posts {
  max-width: 720px;
  margin: 0 auto;
}

.blog-post-preview {
  padding: var(--space-2xl) 0;
  margin-bottom: var(--space-2xl);
  border-bottom: 1px solid var(--border-light);
  transition: all var(--transition-normal);
}

.blog-post-preview:last-child {
  border-bottom: none;
}

.blog-post-preview:hover {
  transform: translateY(-1px);
}

.blog-post-preview h2 {
  margin-bottom: var(--space-md);
  font-size: 1.75rem;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.01em;
}

.blog-post-preview h2 a {
  color: var(--text-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.blog-post-preview h2 a:hover {
  color: var(--accent-primary);
}

.post-meta {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.post-meta time {
  color: var(--text-muted);
  font-weight: 500;
}

.tags {
  display: flex;
  gap: var(--space-sm);
  flex-wrap: wrap;
}

.tag {
  color: var(--accent-primary);
  font-size: 0.8125rem;
  font-weight: 500;
  text-transform: lowercase;
}

.tag:not(:last-child)::after {
  content: "·";
  margin-left: var(--space-sm);
  color: var(--text-muted);
}

.post-summary {
  color: var(--text-secondary);
  line-height: 1.65;
  font-size: 1rem;
  max-width: 90%;
}

/* Individual Post Styles */
.post-header {
  max-width: 800px;
  margin: 0 auto var(--space-3xl);
  text-align: center;
}

.post-title {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: var(--space-md);
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.post-content {
  max-width: 800px;
  margin: 0 auto;
  font-size: 1.125rem;
  line-height: 1.8;
}

.post-content h2,
.post-content h3,
.post-content h4 {
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.post-content p {
  margin-bottom: var(--space-lg);
}

.post-content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  margin: var(--space-xl) 0;
}

.post-content pre {
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  overflow-x: auto;
  margin: var(--space-lg) 0;
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.post-content code {
  background-color: var(--bg-tertiary);
  padding: var(--space-xs) var(--space-sm);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.875rem;
}

.post-content pre code {
  background: none;
  padding: 0;
}

/* Footer Styles */
.site-footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
  margin-top: auto;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-2xl) var(--space-lg);
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: var(--space-2xl);
}

.footer-brand h3 {
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

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

.footer-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-xl);
}

.footer-section h4 {
  color: var(--text-primary);
  margin-bottom: var(--space-md);
  font-size: 1rem;
}

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

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

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

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

.footer-bottom {
  border-top: 1px solid var(--border-light);
  padding: var(--space-lg) 0;
}

.footer-bottom p {
  color: var(--text-muted);
  font-size: 0.875rem;
  text-align: center;
}

/* Responsive Design */
@media (max-width: 768px) {
  .container,
  .header-container {
    padding: 0 var(--space-md);
  }
  
  .header-container {
    height: 3.5rem;
  }
  
  .header-nav {
    display: none;
  }
  
  .brand-link {
    font-size: 1.125rem;
  }
  
  .post-title {
    font-size: 2.5rem;
  }
  
  .blog-post-preview {
    padding: var(--space-lg);
    margin-bottom: var(--space-lg);
  }
  
  .footer-container {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
    padding: var(--space-xl) var(--space-md);
  }
  
  .footer-links {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
  }
}

@media (max-width: 480px) {
  .post-title {
    font-size: 2rem;
  }
  
  .post-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-sm);
  }
}

/* Animation and Transitions */
@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
  
  .blog-post-preview {
    transition: all var(--transition-normal);
  }
  
  .theme-toggle {
    transition: all var(--transition-fast);
  }
}

/* Blog Header */
.blog-header {
  text-align: center;
  margin-bottom: var(--space-3xl);
  padding: var(--space-xl) 0 var(--space-2xl);
}

.blog-header h1 {
  font-size: 2.75rem;
  font-weight: 700;
  margin-bottom: var(--space-lg);
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.blog-description {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 500px;
  margin: 0 auto;
  font-weight: 400;
  line-height: 1.6;
}

/* Breadcrumb Navigation */
.breadcrumb {
  margin-bottom: var(--space-xl);
  font-size: 0.875rem;
  color: var(--text-muted);
}

.breadcrumb a {
  color: var(--accent-primary);
  text-decoration: none;
}

.breadcrumb a:hover {
  text-decoration: underline;
}

/* Post Footer */
.post-footer {
  margin-top: var(--space-3xl);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--border-light);
}

.post-sharing {
  margin-bottom: var(--space-xl);
}

.post-sharing h3 {
  font-size: 1.125rem;
  margin-bottom: var(--space-md);
  color: var(--text-primary);
}

.sharing-buttons {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

.share-button {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition-fast);
}

.share-button:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-medium);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.share-button svg {
  width: 1rem;
  height: 1rem;
}

.post-navigation {
  text-align: center;
}

.back-to-blog {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  background-color: var(--accent-primary);
  color: white;
  text-decoration: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: all var(--transition-fast);
}

.back-to-blog:hover {
  background-color: var(--accent-secondary);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px var(--shadow-medium);
}

/* Focus styles for accessibility */
.theme-toggle:focus,
a:focus,
.share-button:focus {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}