/* 92learns Blog - Clean, Modern, SEO-Optimized */

/* ============================================
   CSS Variables
   ============================================ */
:root {
  /* Colors - subtle warm tint */
  --bg-primary: #181716;
  --bg-secondary: #201e1d;
  --bg-card: #262423;
  --bg-hover: #2e2b2a;
  
  --text-primary: #ffffff;
  --text-secondary: #b0b0b0;
  --text-muted: #666666;
  
  --accent: #ff6431;
  --accent-hover: #ff7a4d;
  --accent-subtle: rgba(255, 100, 49, 0.1);
  
  --border: #2e2c2a;
  --border-light: #383533;
  
  /* Typography */
  --font-heading: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --content-width: 720px;
  --wide-width: 1200px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* ============================================
   Reset & Base
   ============================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  min-height: 100vh;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

h1 {
  font-size: clamp(2rem, 5vw, 2.75rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.5rem, 4vw, 2rem);
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--border);
}

h3 {
  font-size: clamp(1.25rem, 3vw, 1.5rem);
  margin-top: var(--spacing-lg);
}

h4 {
  font-size: 1.125rem;
  margin-top: var(--spacing-md);
}

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

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

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

strong {
  color: var(--text-primary);
  font-weight: 600;
}

/* ============================================
   Layout
   ============================================ */
.container {
  width: 100%;
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.content {
  max-width: var(--content-width);
  margin: 0 auto;
}

/* ============================================
   Header
   ============================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(24, 23, 22, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: var(--spacing-sm) 0;
}

.site-header .progress-container {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 3px;
  background: transparent;
}

.site-header .progress-bar {
  height: 100%;
  width: 0%;
  background: var(--accent);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* Desktop Nav */
.desktop-nav {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

/* Header Right (Mobile only) */
.header-right {
  display: none;
}

/* Burger Menu */
.burger-menu {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 28px;
  height: 28px;
  cursor: pointer;
  padding: 4px;
  background: none;
  border: none;
}

.burger-menu span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s ease;
}

.burger-menu.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.burger-menu.active span:nth-child(2) {
  opacity: 0;
}

.burger-menu.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Nav Overlay */
.mobile-nav {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--bg-primary);
  z-index: 99;
  padding: 80px var(--spacing-md) var(--spacing-lg);
  flex-direction: column;
  gap: var(--spacing-md);
}

.mobile-nav.active {
  display: flex;
}

.mobile-nav a {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--text-primary);
  padding: var(--spacing-sm) 0;
  border-bottom: 1px solid var(--border);
}

.mobile-nav a:hover {
  color: var(--accent);
  text-decoration: none;
}

.mobile-nav .theme-toggle {
  margin-top: var(--spacing-md);
  justify-content: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-family: var(--font-heading);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
}

.logo:hover {
  color: var(--text-primary);
  text-decoration: none;
}

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

.nav-links {
  display: flex;
  gap: var(--spacing-md);
  list-style: none;
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-links a:hover {
  color: var(--text-primary);
  text-decoration: none;
}

/* ============================================
   Hero Section (Homepage)
   ============================================ */
.hero {
  padding: var(--spacing-2xl) 0;
  text-align: center;
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  margin-bottom: var(--spacing-sm);
}

.hero-tagline {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 600px;
  margin: 0 auto;
}

/* ============================================
   Post Grid (Homepage)
   ============================================ */
.posts-section {
  padding: var(--spacing-xl) 0;
}

.section-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--spacing-lg);
}

.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-lg);
}

/* ============================================
   Post Card
   ============================================ */
.post-card {
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  transition: transform var(--transition-normal), 
              border-color var(--transition-normal),
              box-shadow var(--transition-normal);
}

.post-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-light);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
}

.post-card a {
  text-decoration: none;
}

.post-card-image {
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: var(--bg-secondary);
}

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

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

.post-card-content {
  padding: var(--spacing-md);
}

.post-card-category {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-xs);
}

.post-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
  line-height: 1.4;
}

.post-card-excerpt {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: var(--spacing-sm);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-card-meta {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.post-card-date {
  display: flex;
  align-items: center;
  gap: 4px;
}

.post-card-reading-time {
  display: flex;
  align-items: center;
  gap: 4px;
}

.post-card-meta svg {
  width: 14px;
  height: 14px;
  opacity: 0.7;
}

/* ============================================
   Article Page
   ============================================ */
.article {
  padding: var(--spacing-xl) 0 var(--spacing-2xl);
}

.article-header {
  margin-bottom: var(--spacing-xl);
  text-align: center;
}

.article-category {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--spacing-sm);
}

.article-title {
  margin-bottom: var(--spacing-md);
}

.article-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-md);
  color: var(--text-muted);
  font-size: 0.9rem;
  flex-wrap: wrap;
}

.article-author {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.article-author img {
  width: 32px;
  height: 32px;
  border-radius: 50%;
}

/* Article Cover Image */
.article-cover {
  margin: var(--spacing-xl) 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.article-cover img {
  width: 100%;
  height: auto;
  display: block;
}

/* ============================================
   TL;DR Box
   ============================================ */
.tldr {
  background: var(--accent-subtle);
  border: 1px solid var(--accent);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.tldr-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-sm);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.tldr ul {
  margin: 0;
  padding-left: var(--spacing-md);
}

.tldr li {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
}

.tldr li:last-child {
  margin-bottom: 0;
}

/* ============================================
   Table of Contents
   ============================================ */
.toc {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
}

.toc-title {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-sm);
}

.toc ol {
  margin: 0;
  padding-left: var(--spacing-md);
}

.toc li {
  margin-bottom: var(--spacing-xs);
}

.toc a {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

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

/* ============================================
   Article Content
   ============================================ */
.article-content h2:first-of-type {
  margin-top: 0;
  border-top: none;
  padding-top: 0;
}

.article-content ul,
.article-content ol {
  margin-bottom: var(--spacing-md);
  padding-left: var(--spacing-lg);
}

.article-content li {
  margin-bottom: var(--spacing-xs);
  color: var(--text-secondary);
}

.article-content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
  margin: var(--spacing-md) 0;
}

.article-content blockquote {
  border-left: 3px solid var(--accent);
  padding-left: var(--spacing-md);
  margin: var(--spacing-lg) 0;
  font-style: italic;
  color: var(--text-muted);
}

.article-content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--bg-secondary);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
  color: var(--accent);
}

.article-content pre {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  overflow-x: auto;
  margin: var(--spacing-md) 0;
}

.article-content pre code {
  background: none;
  padding: 0;
  color: var(--text-secondary);
}

.article-content table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-md) 0;
}

.article-content th,
.article-content td {
  padding: var(--spacing-sm);
  border: 1px solid var(--border);
  text-align: left;
}

.article-content th {
  background: var(--bg-secondary);
  font-weight: 600;
}

/* ============================================
   FAQ Section
   ============================================ */
.faq {
  margin-top: var(--spacing-xl);
}

.faq-item {
  border-bottom: 1px solid var(--border);
  padding: var(--spacing-md) 0;
}

.faq-item:last-child {
  border-bottom: none;
}

.faq-question {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.faq-answer {
  color: var(--text-secondary);
}

/* ============================================
   Author Bio
   ============================================ */
.author-bio {
  display: flex;
  gap: var(--spacing-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
}

.author-bio-avatar {
  flex-shrink: 0;
}

.author-bio-avatar img {
  width: 80px;
  height: 80px;
  border-radius: 50%;
}

.author-bio-content h4 {
  margin-top: 0;
  margin-bottom: var(--spacing-xs);
}

.author-bio-content p {
  font-size: 0.95rem;
  margin-bottom: var(--spacing-sm);
}

.author-bio-links {
  display: flex;
  gap: var(--spacing-sm);
}

.author-bio-links a {
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

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

/* ============================================
   Course CTA
   ============================================ */
.course-cta {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-secondary) 100%);
  border: 1px solid var(--accent);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  margin: var(--spacing-xl) 0;
  text-align: center;
}

.course-cta h2 {
  margin-top: 0;
  border-top: none;
  padding-top: 0;
  color: var(--text-primary);
}

.course-cta p {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-md);
}

.cta-button {
  display: inline-block;
  background: var(--accent);
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: 1rem;
  font-weight: 700;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: background var(--transition-fast), 
              transform var(--transition-fast);
}

.cta-button:hover {
  background: var(--accent-hover);
  color: #ffffff;
  text-decoration: none;
  transform: translateY(-2px);
}

/* ============================================
   Related Posts
   ============================================ */
.related-posts {
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-xl);
  border-top: 1px solid var(--border);
}

.related-posts h2 {
  margin-top: 0;
  border-top: none;
  padding-top: 0;
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border);
  padding: var(--spacing-xl) 0;
  margin-top: var(--spacing-2xl);
}

.footer-inner {
  max-width: var(--wide-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--spacing-lg);
}

.footer-section h4 {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-sm);
}

.footer-links {
  list-style: none;
}

.footer-links li {
  margin-bottom: var(--spacing-xs);
}

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

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

.footer-bottom {
  max-width: var(--wide-width);
  margin: var(--spacing-lg) auto 0;
  padding: var(--spacing-md) var(--spacing-md) 0;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ============================================
   Newsletter Signup
   ============================================ */
.newsletter {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  margin: var(--spacing-xl) 0;
  text-align: center;
}

.newsletter h3 {
  margin-top: 0;
}

.newsletter p {
  margin-bottom: var(--spacing-md);
}

.newsletter-form {
  display: flex;
  gap: var(--spacing-sm);
  max-width: 400px;
  margin: 0 auto;
}

.newsletter-input {
  flex: 1;
  padding: var(--spacing-sm);
  background: var(--bg-primary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 1rem;
}

.newsletter-input::placeholder {
  color: var(--text-muted);
}

.newsletter-input:focus {
  outline: none;
  border-color: var(--accent);
}

.newsletter-button {
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--accent);
  color: #ffffff;
  border: none;
  border-radius: var(--radius-sm);
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition-fast);
}

.newsletter-button:hover {
  background: var(--accent-hover);
}

/* ============================================
   Search
   ============================================ */
.search-box {
  position: relative;
  max-width: 300px;
}

.search-input {
  width: 100%;
  padding: var(--spacing-xs) var(--spacing-sm);
  padding-left: 36px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-size: 0.9rem;
}

.search-input::placeholder {
  color: var(--text-muted);
}

.search-input:focus {
  outline: none;
  border-color: var(--accent);
}

.search-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-muted);
  width: 18px;
  height: 18px;
}

/* ============================================
   Categories/Tags
   ============================================ */
.categories {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-lg);
}

.category-tag {
  padding: var(--spacing-xs) var(--spacing-sm);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.category-tag:hover,
.category-tag.active {
  background: var(--accent-subtle);
  border-color: var(--accent);
  color: var(--accent);
}

/* ============================================
   Responsive - Tablet (1024px and below)
   ============================================ */
@media (max-width: 1024px) {
  :root {
    --spacing-xl: 2.5rem;
    --spacing-2xl: 3rem;
  }
  
  .container {
    padding: 0 var(--spacing-md);
  }
  
  .posts-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
  }
  
  .footer-inner {
    gap: var(--spacing-xl);
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
}

/* ============================================
   Responsive - Mobile (768px and below)
   ============================================ */
@media (max-width: 768px) {
  /* Mobile header - logo left, burger + theme toggle right */
  .header-inner {
    flex-direction: row;
    padding: 12px 10px !important;
  }
  
  .header-right {
    display: flex;
    align-items: center;
    gap: 12px;
  }
  
  .header-inner .theme-toggle {
    display: flex;
    padding: 6px;
    border: none;
    background: transparent;
  }
  
  .desktop-nav {
    display: none !important;
  }
  
  .header-right {
    display: flex;
  }
  
  /* Padding like Mailchimp - 20px sides */
  .container,
  .content {
    padding: 0 10px;
  }
  
  /* Article */
  .article {
    padding: 0;
  }
  
  .article-header {
    padding: 24px 16px 20px;
    margin-bottom: 0;
  }
  
  .article-category {
    font-size: 12px;
    margin-bottom: 8px;
  }
  
  .article-title {
    font-size: 32px;
    line-height: 1.2;
    font-weight: 700;
  }
  
  .article-meta {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 8px 16px;
    font-size: 14px;
    margin-top: 16px;
  }
  
  .article-cover {
    margin: 0 16px 28px 16px;
    border-radius: 12px;
  }
  
  .article-content {
    padding: 0 16px;
    font-size: 18px;
    line-height: 1.75;
  }
  
  .article-content p {
    margin-bottom: 20px;
  }
  
  .article-content h2 {
    font-size: 26px;
    margin-top: 32px;
    margin-bottom: 16px;
    padding-top: 16px;
  }
  
  .article-content h3 {
    font-size: 21px;
    margin-top: 24px;
  }
  
  /* TL;DR and TOC */
  .tldr {
    margin: 0 16px 24px;
    padding: 20px 18px;
    border-radius: 12px;
  }
  
  .tldr-title {
    font-size: 13px;
    margin-bottom: 14px;
  }
  
  .tldr ul {
    font-size: 16px;
    padding-left: 20px;
  }
  
  .tldr li {
    margin-bottom: 12px;
    line-height: 1.5;
  }
  
  .toc {
    margin: 0 16px 28px;
    padding: 20px 18px;
    border-radius: 12px;
  }
  
  .toc-title {
    font-size: 13px;
    margin-bottom: 16px;
  }
  
  .toc ol {
    padding-left: 8px;
    list-style: none;
    counter-reset: toc-counter;
  }
  
  .toc li {
    counter-increment: toc-counter;
    margin-bottom: 12px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
  }
  
  .toc li::before {
    content: counter(toc-counter) ".";
    color: var(--accent);
    font-weight: 600;
    min-width: 20px;
  }
  
  .toc a {
    font-size: 16px;
    line-height: 1.4;
    color: var(--text-secondary);
  }
  
  /* Hero */
  .hero {
    padding: 32px 10px;
    text-align: left;
  }
  
  .hero h1 {
    font-size: 28px;
  }
  
  .hero-tagline {
    font-size: 16px;
    margin: 0;
  }
  
  /* Posts grid */
  .posts-grid {
    grid-template-columns: 1fr;
    gap: 24px;
  }
  
  .post-card {
    border-radius: 8px;
  }
  
  .post-card-content {
    padding: 16px;
  }
  
  .post-card-title {
    font-size: 18px;
  }
  
  .post-card-excerpt {
    font-size: 14px;
  }
  
  /* Author bio */
  .author-bio {
    flex-direction: column;
    text-align: center;
    padding: 20px;
    margin: 24px 10px;
    border-radius: 8px;
  }
  
  .author-bio-avatar img {
    width: 64px;
    height: 64px;
  }
  
  .author-bio-content h4 {
    font-size: 16px;
  }
  
  .author-bio-content p {
    font-size: 14px;
  }
  
  .author-bio-links {
    justify-content: center;
    font-size: 14px;
  }
  
  /* Course CTA */
  .course-cta {
    padding: 24px 10px;
    margin: 24px 10px;
    border-radius: 8px;
  }
  
  .course-cta h2 {
    font-size: 20px;
    margin-bottom: 8px;
  }
  
  .course-cta p {
    font-size: 15px;
  }
  
  .cta-button {
    width: 100%;
    text-align: center;
    padding: 14px 20px;
    font-size: 16px;
  }
  
  /* Newsletter */
  .newsletter {
    padding: 24px 10px;
    margin: 24px 10px;
    border-radius: 8px;
  }
  
  .newsletter h3 {
    font-size: 18px;
  }
  
  .newsletter p {
    font-size: 14px;
  }
  
  .newsletter-form {
    flex-direction: column;
    gap: 12px;
  }
  
  .newsletter-input,
  .newsletter-button {
    width: 100%;
    padding: 14px;
    font-size: 16px;
  }
  
  /* Footer */
  .site-footer {
    padding: 32px 0;
  }
  
  .footer-inner {
    flex-direction: column;
    text-align: center;
    gap: 24px;
    padding: 0 10px;
  }
  
  .footer-section h4 {
    font-size: 12px;
    margin-bottom: 12px;
  }
  
  .footer-links a {
    font-size: 14px;
  }
  
  .footer-bottom {
    font-size: 12px;
    padding: 16px 10px 0;
  }
  
  /* Related posts */
  .related-posts {
    padding: 24px 10px;
  }
  
  .related-posts h2 {
    font-size: 18px;
    text-align: left;
  }
  
  .related-posts .posts-grid {
    grid-template-columns: 1fr;
  }
  
  /* Categories */
  .categories {
    padding: 0 10px;
    justify-content: flex-start;
    gap: 8px;
  }
  
  .category-tag {
    font-size: 13px;
    padding: 8px 12px;
  }
  
  /* FAQ */
  .faq {
    padding: 0;
  }
  
  .faq-question {
    font-size: 19px;
  }
  
  .faq-answer {
    font-size: 17px;
  }
}

/* ============================================
   Responsive - Small Mobile (480px and below)
   ============================================ */
@media (max-width: 480px) {
  :root {
    --spacing-md: 1rem;
    --spacing-sm: 0.75rem;
  }
  
  .logo {
    font-size: 1.1rem;
  }
  
  .nav-links {
    gap: 0.5rem;
  }
  
  .nav-links a {
    font-size: 0.8rem;
  }
  
  h1, .article-title, .hero h1 {
    font-size: 1.65rem;
  }
  
  h2, .article-content h2 {
    font-size: 1.4rem;
  }
  
  h3, .article-content h3 {
    font-size: 1.2rem;
  }
  
  .post-card-content {
    padding: var(--spacing-sm);
  }
  
  .post-card-title {
    font-size: 1rem;
  }
  
  .post-card-excerpt {
    font-size: 0.85rem;
  }
  
  .tldr {
    padding: var(--spacing-sm);
  }
  
  .tldr-title {
    font-size: 0.85rem;
  }
  
  .toc {
    padding: var(--spacing-sm);
  }
  
  .article-content {
    font-size: 1rem;
    line-height: 1.75;
  }
  
  .faq-question {
    font-size: 1.1rem;
  }
  
  .author-bio {
    padding: var(--spacing-sm);
  }
  
  .course-cta {
    padding: var(--spacing-sm);
  }
}

/* ============================================
   Reading Progress Bar
   ============================================ */
.progress-container {
  position: sticky;
  top: 0;
  left: 0;
  width: 100%;
  height: 4px;
  background: var(--bg-secondary);
  z-index: 99;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: var(--accent);
  transition: width 30ms linear;
}

/* ============================================
   Theme Toggle
   ============================================ */
.theme-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  padding: 6px 12px;
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.85rem;
  transition: all var(--transition-fast);
}

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

.theme-toggle svg {
  width: 16px;
  height: 16px;
}

.theme-toggle .icon-sun {
  display: none;
}

.theme-toggle .icon-moon {
  display: block;
}

/* ============================================
   Light Mode
   ============================================ */
[data-theme="light"] {
  --bg-primary: #ffffff;
  --bg-secondary: #f5f5f5;
  --bg-card: #ffffff;
  --bg-hover: #f0f0f0;
  
  --text-primary: #1a1a1a;
  --text-secondary: #4a4a4a;
  --text-muted: #888888;
  
  --accent: #e5551f;
  --accent-hover: #d04a1a;
  --accent-subtle: rgba(229, 85, 31, 0.1);
  
  --border: #e0e0e0;
  --border-light: #d0d0d0;
}

[data-theme="light"] .site-header {
  background: rgba(255, 255, 255, 0.95);
  border-bottom-color: #e0e0e0;
}

[data-theme="light"] .theme-toggle .icon-sun {
  display: block;
}

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

[data-theme="light"] .post-card {
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

[data-theme="light"] .post-card:hover {
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
}

[data-theme="light"] .tldr {
  background: rgba(229, 85, 31, 0.08);
}

[data-theme="light"] .article-content code {
  background: #f0f0f0;
}

[data-theme="light"] .article-content pre {
  background: #f5f5f5;
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
  .site-header,
  .site-footer,
  .course-cta,
  .newsletter,
  .related-posts {
    display: none;
  }
  
  body {
    background: white;
    color: black;
  }
  
  .article-content {
    max-width: 100%;
  }
}

/* ============================================
   Utilities
   ============================================ */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

.mt-0 {
  margin-top: 0;
}

.mb-0 {
  margin-bottom: 0;
}