/* ==============================================
   Main Stylesheet — Content Site
   Zero-framework, performance-first CSS
   ============================================== */

/* --- CSS Variables --- */
:root {
  /* Colors */
  --color-primary: #1a73e8;
  --color-primary-dark: #1557b0;
  --color-text: #222222;
  --color-text-light: #555555;
  --color-text-lighter: #777777;
  --color-bg: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-border: #e0e0e0;
  --color-accent: #0d6efd;
  --color-success: #0f9d58;
  --color-warning: #f4b400;
  --color-error: #db4437;

  /* Typography */
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  --font-heading: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", monospace;
  --font-size-base: 18px;
  --font-size-sm: 14px;
  --font-size-lg: 20px;
  --font-size-xl: 24px;
  --font-size-2xl: 32px;
  --font-size-3xl: 40px;
  --line-height: 1.7;

  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;

  /* Layout */
  --container-max: 1200px;
  --content-width: 68%;
  --sidebar-width: 30%;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);

  /* Border Radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Transitions */
  --transition: 0.2s ease;
}

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

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: var(--line-height);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* --- Content Layout (Article + Sidebar) --- */
.content-layout {
  display: flex;
  gap: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  padding-bottom: var(--spacing-2xl);
}

.article-content {
  flex: 0 0 var(--content-width);
  max-width: var(--content-width);
  min-width: 0; /* prevent overflow */
}

.article-content-wide {
  flex: 1;
  min-width: 0;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  line-height: 1.3;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
  scroll-margin-top: 80px;
}

h1 { font-size: var(--font-size-3xl); font-weight: 800; }
h2 { font-size: var(--font-size-2xl); font-weight: 700; margin-top: var(--spacing-xl); }
h3 { font-size: var(--font-size-xl); font-weight: 600; margin-top: var(--spacing-lg); }
h4 { font-size: var(--font-size-lg); font-weight: 600; }

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

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

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

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

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

blockquote {
  border-left: 4px solid var(--color-primary);
  margin: var(--spacing-md) 0;
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-bg-alt);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--color-text-light);
}

blockquote p:last-child {
  margin-bottom: 0;
}

img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-md);
}

figure {
  margin: var(--spacing-md) 0;
}

figcaption {
  font-size: var(--font-size-sm);
  color: var(--color-text-lighter);
  text-align: center;
  margin-top: var(--spacing-xs);
}

code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-bg-alt);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
}

pre {
  background: #1e1e1e;
  color: #d4d4d4;
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

pre code {
  background: none;
  padding: 0;
}

/* --- Tables (Critical for comparison content) --- */
table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: var(--spacing-md);
  font-size: 16px;
}

th, td {
  padding: 12px 16px;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

th {
  background: var(--color-bg-alt);
  font-weight: 600;
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
}

tr:hover td {
  background: #f8f9fa;
}

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
  height: 64px;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.site-logo {
  font-size: var(--font-size-xl);
  font-weight: 800;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -0.5px;
}

.site-logo:hover {
  text-decoration: none;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: var(--spacing-sm);
  margin: 0;
  padding: 0;
}

.nav-link {
  color: var(--color-text-light);
  font-size: var(--font-size-sm);
  font-weight: 500;
  padding: 8px 12px;
  border-radius: var(--radius-md);
  transition: all var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
  background: rgba(26,115,232,0.08);
  text-decoration: none;
}

.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

/* --- Hero --- */
.hero {
  background: linear-gradient(135deg, #1a73e8 0%, #0d6efd 100%);
  color: #fff;
  padding: var(--spacing-2xl) 0;
  text-align: center;
}

.hero-title {
  color: #fff;
  font-size: 48px;
  font-weight: 900;
  margin-bottom: var(--spacing-sm);
  letter-spacing: -1px;
}

.hero-subtitle {
  font-size: var(--font-size-lg);
  opacity: 0.9;
  max-width: 600px;
  margin: 0 auto;
}

/* --- Sections --- */
.section-title {
  margin-top: 0;
  padding-bottom: var(--spacing-sm);
  border-bottom: 3px solid var(--color-primary);
  display: inline-block;
  margin-bottom: var(--spacing-lg);
}

.section-title a {
  color: var(--color-text);
}

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

.latest-posts,
.category-section {
  margin-bottom: var(--spacing-2xl);
}

/* --- Post Card Grid --- */
.post-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
}

.post-grid-compact {
  grid-template-columns: repeat(3, 1fr);
}

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

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

.post-card-image img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  border-radius: 0;
}

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

.post-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  align-items: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-lighter);
  margin-bottom: var(--spacing-xs);
}

.post-card-meta svg {
  vertical-align: -2px;
  margin-right: 2px;
}

.post-category {
  display: inline-block;
  background: rgba(26,115,232,0.1);
  color: var(--color-primary);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 4px 10px;
  border-radius: 20px;
}

.post-category:hover {
  background: var(--color-primary);
  color: #fff;
  text-decoration: none;
}

.post-card-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin: var(--spacing-xs) 0;
  line-height: 1.35;
}

.post-card-title a {
  color: var(--color-text);
}

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

.post-card-excerpt {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
  line-height: 1.5;
  margin-bottom: var(--spacing-sm);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.tag {
  font-size: 12px;
  color: var(--color-text-lighter);
  padding: 2px 8px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  transition: all var(--transition);
}

.tag svg {
  width: 12px;
  height: 12px;
  vertical-align: -2px;
}

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

/* --- Article Detail --- */
.article-header {
  margin-bottom: var(--spacing-lg);
}

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

.article-subtitle {
  font-size: var(--font-size-lg);
  color: var(--color-text-light);
}

.article-meta {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-lighter);
  flex-wrap: wrap;
}

.article-meta svg {
  vertical-align: -2px;
}

.article-body {
  font-size: var(--font-size-base);
}

.article-body > *:first-child {
  margin-top: 0;
}

.article-body h2 {
  font-size: 28px;
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
}

.article-body h3 {
  font-size: 22px;
}

/* Tip / Warning boxes */
.tip-box,
.warning-box {
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  margin: var(--spacing-md) 0;
  font-size: 16px;
}

.tip-box {
  background: #e8f5e9;
  border-left: 4px solid var(--color-success);
}

.warning-box {
  background: #fff3e0;
  border-left: 4px solid var(--color-warning);
}

.tip-box p:last-child,
.warning-box p:last-child {
  margin-bottom: 0;
}

/* --- Sidebar --- */
.sidebar {
  flex: 1;
  min-width: 280px;
}

.sidebar-widget {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.widget-title {
  font-size: var(--font-size-lg);
  margin-top: 0;
  margin-bottom: var(--spacing-sm);
  padding-bottom: var(--spacing-xs);
  border-bottom: 2px solid var(--color-primary);
}

.popular-posts,
.category-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.popular-posts li,
.category-list li {
  padding: 8px 0;
  border-bottom: 1px solid var(--color-border);
}

.popular-posts li:last-child,
.category-list li:last-child {
  border-bottom: none;
}

.popular-posts a {
  font-size: 15px;
  font-weight: 500;
  display: block;
}

.post-date-small {
  font-size: 12px;
  color: var(--color-text-lighter);
}

.sidebar-ad {
  text-align: center;
  padding: 0;
  border: none;
  background: transparent;
}

/* --- Ad Containers --- */
.ad-container {
  margin: var(--spacing-md) 0;
  text-align: center;
  min-height: 90px;
  background: var(--color-bg-alt);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.ad-placeholder {
  /* Only visible in dev mode */
}

.in-feed-ad {
  margin: var(--spacing-xl) 0;
}

/* --- Article Tags --- */
.article-tags {
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

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

.related-posts h2 {
  margin-top: 0;
  border-top: none;
  padding-top: 0;
}

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

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-lg);
  justify-content: space-between;
}

.footer-title {
  font-size: var(--font-size-lg);
  font-weight: 700;
  margin-bottom: 4px;
}

.footer-tagline {
  font-size: var(--font-size-sm);
  color: var(--color-text-lighter);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-md);
  align-items: center;
}

.footer-links a {
  font-size: var(--font-size-sm);
  color: var(--color-text-light);
}

.footer-bottom {
  width: 100%;
  padding-top: var(--spacing-md);
  border-top: 1px solid var(--color-border);
  font-size: var(--font-size-sm);
  color: var(--color-text-lighter);
  text-align: center;
}

.footer-disclosure {
  font-style: italic;
  margin-top: var(--spacing-xs);
}

/* --- Responsive --- */
@media (max-width: 1024px) {
  .content-layout {
    flex-direction: column;
  }

  .article-content {
    flex: 1;
    max-width: 100%;
  }

  .sidebar {
    min-width: 0;
  }

  .post-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  :root {
    --font-size-base: 16px;
    --font-size-3xl: 32px;
    --font-size-2xl: 26px;
    --font-size-xl: 20px;
  }

  .hero-title {
    font-size: 36px;
  }

  .post-grid,
  .post-grid-compact {
    grid-template-columns: 1fr;
  }

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

  .nav-list {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: #fff;
    flex-direction: column;
    padding: var(--spacing-sm);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }

  .nav-list.open {
    display: flex;
  }

  .article-body h2 {
    font-size: 24px;
    margin-top: 32px;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }

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

/* --- Print --- */
@media print {
  .site-header,
  .site-footer,
  .sidebar,
  .ad-container,
  .ad-placeholder {
    display: none;
  }

  .article-content {
    flex: 1;
    max-width: 100%;
  }
}