/* ============================================
   eSIM Global Blog - Notion Design System v2
   Clean, minimal, content-first design
   Compatible with esim-global header/footer
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Noto+Sans+JP:wght@400;500;600;700&display=swap');

/* ============================================
   CSS Variables - Notion Design System
   ============================================ */
:root {
  /* Typography */
  --font-sans: 'Inter', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif;
  
  /* Colors */
  --bg-primary: #f6f5f4;        /* Warm White */
  --bg-surface: #ffffff;         /* Pure White */
  --text-primary: rgba(0, 0, 0, 0.95);   /* Near-Black */
  --text-secondary: rgba(0, 0, 0, 0.65);
  --text-tertiary: rgba(0, 0, 0, 0.45);
  --accent: #0075de;             /* Notion Blue */
  --accent-hover: #005fb8;
  
  /* Borders */
  --border-default: 1px solid rgba(0, 0, 0, 0.1);
  --border-hover: 1px solid rgba(0, 0, 0, 0.2);
  --radius: 4px;
  
  /* Shadows - 4-5 layer low opacity stack */
  --shadow-sm: 
    0 1px 2px rgba(0, 0, 0, 0.04),
    0 2px 4px rgba(0, 0, 0, 0.04);
  --shadow-md: 
    0 1px 2px rgba(0, 0, 0, 0.04),
    0 2px 4px rgba(0, 0, 0, 0.04),
    0 4px 8px rgba(0, 0, 0, 0.04);
  --shadow-lg: 
    0 1px 2px rgba(0, 0, 0, 0.04),
    0 2px 4px rgba(0, 0, 0, 0.04),
    0 4px 8px rgba(0, 0, 0, 0.04),
    0 8px 16px rgba(0, 0, 0, 0.04),
    0 16px 32px rgba(0, 0, 0, 0.04);
  
  /* Spacing - 8px base */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  --spacing-3xl: 96px;
  
  /* Layout */
  --container-max: 1200px;
  --content-width: 720px;
  --sidebar-width: 320px;
  --header-height: 64px;
  
  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
}

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

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

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

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

/* ============================================
   Skip Link - Accessibility
   ============================================ */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--accent);
  color: #fff;
  padding: var(--spacing-xs) var(--spacing-sm);
  z-index: 1001;
  font-weight: 500;
  transition: top var(--transition-fast);
  text-decoration: none;
  border-radius: 0 0 var(--radius) 0;
}

.skip-link:focus {
  top: 0;
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ============================================
   Header - Matches esim-global main site
   Overridden for Notion blog aesthetic
   ============================================ */
.blog-page header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: var(--border-default);
  height: 72px;
}

.blog-page header .container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
  height: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.blog-page .logo a {
  font-family: 'Inter', 'Noto Sans JP', sans-serif;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  text-decoration: none;
}

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

.blog-page .logo a::before {
  content: '🌍';
  font-size: 1.2rem;
}

.blog-page nav ul {
  list-style: none;
  display: flex;
  gap: var(--spacing-xs);
}

.blog-page nav a {
  display: block;
  padding: 10px 16px;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.blog-page nav a:hover,
.blog-page nav a.active {
  background: var(--bg-primary);
  color: var(--accent);
  text-decoration: none;
}

/* Mobile Menu Toggle - Notion Style */
.blog-page .menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-xs);
}

.blog-page .menu-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

/* ============================================
   Main Layout - Notion-inspired Blog
   ============================================ */
.blog-page {
  background: var(--bg-primary);
  padding-top: 72px; /* Match main site header height */
}

.blog-main {
  padding-top: var(--spacing-2xl);
  padding-bottom: var(--spacing-3xl);
  min-height: calc(100vh - 72px - 300px); /* Account for header and footer */
}

.blog-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: var(--spacing-2xl);
  align-items: start;
}

.main-content {
  min-width: 0;
}

/* ============================================
   Blog List Page Header - Notion Style
   ============================================ */
.blog-header {
  max-width: var(--container-max);
  margin: 0 auto var(--spacing-2xl);
  padding: var(--spacing-2xl) var(--spacing-md) var(--spacing-xl);
  text-align: left;
  border-bottom: var(--border-default);
}

.blog-header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
  letter-spacing: -0.02em;
}

.blog-header p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0;
}

/* ============================================
   Blog Grid - Notion Card Style
   ============================================ */
.blog-list {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-lg);
}

/* Blog Card - Notion Style */
.blog-card {
  background: var(--bg-surface);
  border: var(--border-default);
  border-radius: var(--radius);
  overflow: hidden;
  transition: all var(--transition-base);
  box-shadow: var(--shadow-sm);
}

.blog-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: rgba(0, 0, 0, 0.15);
}

.blog-card a {
  color: inherit;
  text-decoration: none;
  display: block;
}

.blog-card:hover .blog-content h2 {
  color: var(--accent);
}

/* Card Thumbnail with Aspect Ratio */
.blog-thumbnail {
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: linear-gradient(135deg, #f0f0f0 0%, #e0e0e0 100%);
  display: block;
}

/* Card Content */
.blog-content {
  padding: var(--spacing-md);
}

.blog-content h2 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0 0 var(--spacing-xs);
  line-height: 1.4;
  letter-spacing: -0.01em;
  transition: color var(--transition-fast);
}

.blog-content time {
  display: block;
  font-size: 0.8125rem;
  color: var(--text-tertiary);
  margin-bottom: var(--spacing-xs);
  font-weight: 500;
}

.blog-content .article-summary {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: var(--spacing-sm);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.blog-content .read-more {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--accent);
}

.blog-content .read-more:hover {
  text-decoration: none;
  color: var(--accent-hover);
}

/* ============================================
   Article Detail Page (template.html)
   ============================================ */
.article-wrapper {
  background: var(--bg-surface);
  border: var(--border-default);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

/* Featured Image - Full Width Eyecatch */
.featured-image {
  width: 100%;
  aspect-ratio: 21 / 9;
  object-fit: cover;
  background: linear-gradient(135deg, #f5f5f5 0%, #e8e8e8 100%);
  border-bottom: var(--border-default);
  display: block;
}

/* Article Header */
.article-header {
  padding: var(--spacing-2xl) var(--spacing-2xl) var(--spacing-lg);
  border-bottom: var(--border-default);
}

.article-header h1 {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 0 0 var(--spacing-sm);
  line-height: 1.3;
  letter-spacing: -0.02em;
}

.article-meta {
  font-size: 0.9rem;
  color: var(--text-tertiary);
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
}

.article-meta time {
  font-weight: 500;
}

/* Article Body - Notion Typography */
.article-body {
  padding: var(--spacing-2xl);
  font-size: 1.0625rem;
  line-height: 1.8;
  color: var(--text-primary);
}

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

.article-body h2 {
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: var(--spacing-2xl) 0 var(--spacing-md);
  letter-spacing: -0.015em;
  line-height: 1.3;
}

.article-body h3 {
  font-size: 1.375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: var(--spacing-xl) 0 var(--spacing-sm);
  letter-spacing: -0.01em;
  line-height: 1.4;
}

.article-body h4 {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: var(--spacing-lg) 0 var(--spacing-xs);
}

.article-body p {
  margin: 0 0 var(--spacing-md);
  color: var(--text-primary);
}

.article-body a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

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

.article-body ul,
.article-body ol {
  margin: 0 0 var(--spacing-md) var(--spacing-md);
  padding: 0;
}

.article-body li {
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
  line-height: 1.7;
}

.article-body ul li {
  list-style-type: disc;
}

.article-body ol li {
  list-style-type: decimal;
}

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

.article-body blockquote {
  border-left: 3px solid var(--accent);
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-sm) 0 var(--spacing-sm) var(--spacing-md);
  color: var(--text-secondary);
  font-style: italic;
  background: var(--bg-primary);
  border-radius: 0 var(--radius) var(--radius) 0;
}

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

.article-body code {
  background: var(--bg-primary);
  padding: 2px 6px;
  border-radius: 3px;
  font-family: 'SF Mono', Monaco, 'Courier New', monospace;
  font-size: 0.9em;
  color: var(--text-primary);
}

.article-body pre {
  background: var(--bg-primary);
  padding: var(--spacing-md);
  border-radius: var(--radius);
  overflow-x: auto;
  margin: var(--spacing-md) 0;
  border: var(--border-default);
}

.article-body pre code {
  background: none;
  padding: 0;
}

/* Highlight Box */
.highlight-box,
.data-reference {
  background: var(--bg-primary);
  border: var(--border-default);
  border-radius: var(--radius);
  padding: var(--spacing-md);
  margin: var(--spacing-lg) 0;
}

.highlight-box h3,
.data-reference h3 {
  margin-top: 0;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* Share Buttons - Notion Style */
.share-buttons {
  margin-top: var(--spacing-2xl);
  padding-top: var(--spacing-lg);
  border-top: var(--border-default);
}

.share-buttons h3 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-sm);
}

.share-buttons a {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: 8px 16px;
  border: var(--border-default);
  border-radius: var(--radius);
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  transition: all var(--transition-fast);
  background: var(--bg-surface);
  margin-right: var(--spacing-xs);
  margin-bottom: var(--spacing-xs);
  text-decoration: none;
}

.share-buttons a:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--bg-primary);
  text-decoration: none;
}

/* ============================================
   Sidebar - Notion Style
   ============================================ */
.sidebar {
  position: sticky;
  top: calc(72px + var(--spacing-lg));
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

/* Table of Contents - Notion Style */
.toc {
  background: var(--bg-surface);
  border: var(--border-default);
  border-radius: var(--radius);
  padding: var(--spacing-md);
}

.toc h3 {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0 0 var(--spacing-sm);
  padding-bottom: var(--spacing-sm);
  border-bottom: var(--border-default);
}

#toc-list {
  font-size: 0.875rem;
}

#toc-list ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

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

#toc-list a {
  color: var(--text-secondary);
  line-height: 1.5;
  text-decoration: none;
  display: block;
  padding: 4px 0;
  transition: color var(--transition-fast);
}

#toc-list a:hover {
  color: var(--accent);
  text-decoration: none;
}

/* Related Articles - Notion Style */
.related-articles {
  background: var(--bg-surface);
  border: var(--border-default);
  border-radius: var(--radius);
  padding: var(--spacing-md);
}

.related-articles h3 {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0 0 var(--spacing-sm);
  padding-bottom: var(--spacing-sm);
  border-bottom: var(--border-default);
}

.related-articles ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.related-articles li {
  margin-bottom: var(--spacing-sm);
}

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

.related-articles a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
  text-decoration: none;
  display: block;
  transition: color var(--transition-fast);
}

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

/* ============================================
   Footer - Notion Style
   ============================================ */
.blog-page footer {
  background: var(--bg-surface);
  border-top: var(--border-default);
  padding: var(--spacing-2xl) 0 var(--spacing-lg);
}

.blog-page footer .container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.blog-page .footer-content {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--spacing-2xl);
  margin-bottom: var(--spacing-xl);
}

.blog-page .footer-brand h3 {
  font-family: 'Inter', 'Noto Sans JP', sans-serif;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--spacing-sm);
}

.blog-page .footer-brand p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.blog-page .footer-links h4 {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--spacing-sm);
}

.blog-page .footer-links ul {
  list-style: none;
}

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

.blog-page .footer-links a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  text-decoration: none;
}

.blog-page .footer-links a:hover {
  color: var(--accent);
  text-decoration: none;
}

.blog-page .footer-bottom {
  padding-top: var(--spacing-lg);
  border-top: var(--border-default);
  text-align: center;
}

.blog-page .footer-bottom p {
  font-size: 0.8125rem;
  color: var(--text-tertiary);
}

/* ============================================
   Responsive Design - Notion Blog
   ============================================ */
@media (max-width: 960px) {
  .blog-container {
    grid-template-columns: 1fr;
    gap: var(--spacing-xl);
  }
  
  .sidebar {
    position: static;
    order: -1;
  }
  
  .blog-page .footer-content {
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
  }
  
  .article-header {
    padding: var(--spacing-xl) var(--spacing-lg) var(--spacing-lg);
  }
  
  .article-header h1 {
    font-size: 1.875rem;
  }
  
  .article-body {
    padding: var(--spacing-xl);
  }
}

@media (max-width: 768px) {
  .blog-page {
    padding-top: 64px;
  }
  
  .blog-page header {
    height: 64px;
  }
  
  .blog-page .menu-toggle {
    display: flex;
  }
  
  .blog-page nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg-surface);
    border-bottom: var(--border-default);
    padding: var(--spacing-sm);
    display: none;
  }
  
  .blog-page nav.active {
    display: block;
  }
  
  .blog-page nav ul {
    flex-direction: column;
    gap: 0;
  }
  
  .blog-page nav a {
    padding: var(--spacing-sm);
  }
  
  .blog-header {
    padding: var(--spacing-xl) var(--spacing-md);
  }
  
  .blog-header h1 {
    font-size: 1.75rem;
  }
  
  .blog-list {
    grid-template-columns: 1fr;
  }
  
  .featured-image {
    aspect-ratio: 16 / 9;
  }
  
  .article-header {
    padding: var(--spacing-lg);
  }
  
  .article-header h1 {
    font-size: 1.5rem;
  }
  
  .article-body {
    padding: var(--spacing-lg);
    font-size: 1rem;
  }
  
  .article-body h2 {
    font-size: 1.5rem;
  }
  
  .article-body h3 {
    font-size: 1.25rem;
  }
  
  .blog-page .footer-content {
    grid-template-columns: 1fr;
    gap: var(--spacing-lg);
  }
}

@media (max-width: 480px) {
  .blog-header {
    padding: var(--spacing-lg) var(--spacing-sm);
  }
  
  .blog-content {
    padding: var(--spacing-sm);
  }
  
  .article-header,
  .article-body {
    padding: var(--spacing-md);
  }
  
  .article-header h1 {
    font-size: 1.375rem;
  }
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
  header,
  .sidebar,
  footer,
  .share-buttons {
    display: none;
  }
  
  .blog-container {
    display: block;
  }
  
  .article-wrapper {
    box-shadow: none;
    border: none;
  }
}