/* AI Curation Site - Main CSS */

/* CSS Variables - Gentle Design Theme (WCAG AA Compliant) */
:root {
  --primary-color: #4f80c7;
  --primary-color-dark: #3e6ba3;
  --secondary-color: #3968a3;
  --accent-color: #5d88d4;
  --text-color: #3a4a5c;
  --text-secondary: #5a6c7e;
  --text-light: #5a6c7e;
  --bg-color: #fafbfc;
  --bg-secondary: #f5f7fa;
  --bg-tertiary: #ecf0f4;
  --border-color: #e8edf3;
  --border-light: #f0f3f7;
  --shadow-soft: 0 2px 8px rgba(0, 0, 0, 0.04);
  --shadow-medium: 0 4px 16px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.08);
  --border-radius: 0.5rem;
  --border-radius-sm: 0.375rem;
  --max-width: 1200px;
  --font-family: -apple-system, BlinkMacSystemFont, 'Hiragino Sans', 'Hiragino Kaku Gothic ProN', 'Yu Gothic', 'Meiryo', 'Segoe UI', Roboto, sans-serif;
  --line-height-base: 1.7;
  --line-height-heading: 1.4;
}

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

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--primary-color);
  color: white;
  padding: 8px 16px;
  text-decoration: none;
  border-radius: var(--border-radius);
  font-size: 0.875rem;
  transition: top 0.3s;
  z-index: 9999;
}

.skip-link:focus {
  top: 6px;
}

body {
  font-family: var(--font-family);
  line-height: var(--line-height-base);
  color: var(--text-color);
  background: linear-gradient(180deg, var(--bg-color) 0%, var(--bg-secondary) 100%);
  background-attachment: fixed;
  font-size: 16px;
  letter-spacing: 0.02em;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: var(--line-height-heading);
  margin-bottom: 1.25rem;
  color: var(--text-color);
  letter-spacing: -0.01em;
}

h1 { font-size: 2.5rem; margin-bottom: 1.5rem; }
h2 { font-size: 2rem; margin-bottom: 1.25rem; }
h3 { font-size: 1.625rem; margin-bottom: 1rem; }
h4 { font-size: 1.375rem; margin-bottom: 1rem; }
h5 { font-size: 1.125rem; margin-bottom: 0.875rem; }
h6 { font-size: 1rem; margin-bottom: 0.75rem; }

p {
  margin-bottom: 1.25rem;
  line-height: var(--line-height-base);
}

a {
  color: var(--primary-color-dark);
  text-decoration: none;
  transition: color 0.2s ease;
}

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

/* Header */
.header {
  background: rgba(250, 251, 252, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-soft);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem;
}

.site-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0;
}

.site-title a {
  color: var(--text-color);
  text-decoration: none;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: 2rem;
  align-items: center;
}

.nav-list a {
  color: var(--text-color);
  font-weight: 500;
  padding: 0.5rem 0;
  transition: color 0.2s ease;
}

.nav-list a:hover {
  color: var(--primary-color-dark);
}

/* Main Content */
.main {
  min-height: calc(100vh - 200px);
  padding: 3rem 0;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 4rem 0;
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 50%, var(--bg-color) 100%);
  margin-bottom: 3rem;
  border-radius: var(--border-radius);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at 30% 20%, rgba(79, 128, 199, 0.05) 0%, transparent 50%),
              radial-gradient(circle at 70% 80%, rgba(93, 136, 212, 0.03) 0%, transparent 50%);
  pointer-events: none;
}

.hero h1 {
  font-size: 3.25rem;
  margin-bottom: 1.5rem;
  color: var(--text-color);
  font-weight: 700;
  position: relative;
  z-index: 1;
}

.hero p {
  font-size: 1.375rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.6;
  position: relative;
  z-index: 1;
}

/* Search */
.search-container {
  margin: 2rem 0;
}

.search-input {
  width: 100%;
  padding: 1rem 1.25rem;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: 1.0625rem;
  background: var(--bg-color);
  box-shadow: var(--shadow-soft);
  transition: all 0.3s ease;
}

.search-input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(79, 128, 199, 0.1), var(--shadow-medium);
  transform: translateY(-1px);
}

.search-results {
  margin-top: 1rem;
}

.search-result {
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  margin-bottom: 1rem;
  background-color: var(--bg-color);
}

.search-result-title {
  margin-bottom: 0.5rem;
}

.search-result-date {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.search-result-description {
  color: var(--text-secondary);
  margin: 0.5rem 0;
}

.search-no-results {
  text-align: center;
  color: var(--text-secondary);
  padding: 2rem;
}

/* Article Grid */
.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 2.5rem;
  margin: 3rem 0;
}

.article-card {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 2rem;
  transition: all 0.3s ease;
  box-shadow: var(--shadow-soft);
}

.article-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--primary-color);
}

.card-header {
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
}

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

.card-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.5rem;
}

.card-date {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.card-category {
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: var(--border-radius);
  font-size: 0.75rem;
  font-weight: 500;
}

.card-excerpt {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.card-footer {
  border-top: 1px solid var(--border-light);
  padding-top: 1rem;
}

/* Tags */
.tag, .card-tags a {
  display: inline-block;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: var(--border-radius);
  font-size: 0.75rem;
  font-weight: 500;
  margin-right: 0.5rem;
  margin-bottom: 0.5rem;
  transition: background-color 0.2s ease;
}

.tag:hover, .card-tags a:hover {
  background-color: var(--primary-color);
  color: white;
}

.current-tag {
  background-color: var(--primary-color);
  color: white;
}

/* Article Page */
.article-layout {
  display: grid;
  grid-template-columns: 1fr 300px;
  gap: 3rem;
  max-width: 1200px;
  margin: 0 auto;
}

.article {
  max-width: 800px;
  margin: 0;
}

.article-header {
  margin-bottom: 2rem;
  text-align: center;
}

.article-title {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.article-meta {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.article-content {
  line-height: var(--line-height-base);
  margin-bottom: 3rem;
  font-size: 1.0625rem;
}

.article-content h2,
.article-content h3,
.article-content h4 {
  margin-top: 2.5rem;
  margin-bottom: 1.25rem;
  padding-top: 0.5rem;
}

.article-content p {
  margin-bottom: 1.75rem;
  line-height: var(--line-height-base);
}

.article-content ul,
.article-content ol {
  margin-bottom: 1.5rem;
  padding-left: 2rem;
}

.article-content li {
  margin-bottom: 0.5rem;
}

.article-content blockquote {
  border-left: 4px solid var(--primary-color);
  padding-left: 1rem;
  margin: 1.5rem 0;
  color: var(--text-secondary);
  font-style: italic;
}

.article-content code {
  background-color: var(--bg-secondary);
  padding: 0.25rem 0.5rem;
  border-radius: var(--border-radius);
  font-family: 'Courier New', monospace;
  font-size: 0.875rem;
}

.article-content pre {
  background-color: var(--bg-secondary);
  padding: 1rem;
  border-radius: var(--border-radius);
  overflow-x: auto;
  margin: 1.5rem 0;
}

.article-content pre code {
  background-color: transparent;
  padding: 0;
}

/* Article Sidebar */
.article-sidebar {
  position: sticky;
  top: 100px;
  height: fit-content;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: 1.5rem;
  box-shadow: var(--shadow-soft);
}

.sidebar-section {
  margin-bottom: 2rem;
}

.sidebar-section:last-child {
  margin-bottom: 0;
}

.sidebar-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--text-color);
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 0.5rem;
}

/* Table of Contents */
.table-of-contents {
  margin-bottom: 0;
}

.toc-list {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.toc-list li {
  margin-bottom: 0.5rem;
}

.toc-list a {
  display: block;
  padding: 0.375rem 0.75rem;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--border-radius-sm);
  transition: all 0.2s ease;
  font-size: 0.9375rem;
  line-height: 1.4;
}

.toc-list a:hover {
  background-color: var(--bg-secondary);
  color: var(--primary-color-dark);
}

.toc-list a.active {
  background-color: var(--primary-color);
  color: white;
}

.toc-list .toc-h3 {
  padding-left: 1.5rem;
  font-size: 0.875rem;
}

.toc-list .toc-h4 {
  padding-left: 2.25rem;
  font-size: 0.8125rem;
}

/* Sidebar Tags */
.sidebar-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.sidebar-tags .tag {
  font-size: 0.75rem;
  padding: 0.25rem 0.5rem;
}

/* Related Articles */
.related-articles {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.related-article {
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius-sm);
  border: 1px solid var(--border-light);
  transition: all 0.2s ease;
}

.related-article:hover {
  background-color: var(--bg-tertiary);
  transform: translateY(-1px);
}

.related-title {
  font-size: 0.9375rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  line-height: 1.4;
}

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

.related-date {
  font-size: 0.8125rem;
  color: var(--text-secondary);
}

/* Sidebar Navigation */
.sidebar-navigation {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.nav-item {
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius-sm);
  border: 1px solid var(--border-light);
  transition: all 0.2s ease;
}

.nav-item:hover {
  background-color: var(--bg-tertiary);
}

.nav-label {
  display: block;
  font-size: 0.8125rem;
  color: var(--text-secondary);
  margin-bottom: 0.25rem;
  font-weight: 500;
}

.nav-item .nav-title {
  color: var(--text-color);
  font-size: 0.9375rem;
  font-weight: 600;
  line-height: 1.4;
}

/* Category Pages */
.category-page {
  margin: 2rem 0;
}

.category-header {
  text-align: center;
  margin-bottom: 2rem;
}

.category-title {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.category-description {
  color: var(--text-secondary);
  font-size: 1.25rem;
  max-width: 600px;
  margin: 0 auto;
}

/* Pages */
.page-header {
  text-align: center;
  margin-bottom: 2rem;
}

.page-header h1 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.page-header p {
  color: var(--text-secondary);
  font-size: 1.25rem;
}

/* Tags Cloud */
.tags-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 2rem 0;
}

.tag-link {
  display: inline-block;
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  padding: 0.5rem 1rem;
  border-radius: var(--border-radius);
  font-weight: 500;
  transition: all 0.2s ease;
  border: 1px solid var(--border-color);
}

.tag-link:hover {
  background-color: var(--primary-color);
  color: white;
  transform: translateY(-1px);
}

.tag-link[data-count="1"] { font-size: 0.875rem; }
.tag-link[data-count="2"] { font-size: 1rem; }
.tag-link[data-count="3"] { font-size: 1.125rem; }
.tag-link[data-count="4"] { font-size: 1.25rem; }
.tag-link[data-count="5"] { font-size: 1.375rem; }

/* Archives */
.archives-list {
  margin: 2rem 0;
}

.archive-year {
  margin-bottom: 3rem;
}

.year-title {
  font-size: 2rem;
  margin-bottom: 1rem;
  color: var(--primary-color);
}

.archive-month {
  margin-bottom: 2rem;
  padding-left: 2rem;
}

.month-title {
  font-size: 1.5rem;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.post-count {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: normal;
}

.archive-posts {
  list-style: none;
  padding-left: 1rem;
}

.archive-post {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-light);
}

.archive-date {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

.more-posts {
  font-style: italic;
  color: var(--text-secondary);
}

/* Navigation */
.article-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  margin: 2rem 0;
}

.nav-link {
  display: block;
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  transition: all 0.2s ease;
}

.nav-link:hover {
  background-color: var(--bg-secondary);
  transform: translateY(-1px);
}

.nav-label {
  display: block;
  color: var(--text-secondary);
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.nav-title {
  display: block;
  font-weight: 600;
  color: var(--text-color);
}

/* Advertisement Placeholders */
.ad-placeholder {
  margin: 2rem 0;
  padding: 2rem;
  background-color: var(--bg-secondary);
  border: 2px dashed var(--border-color);
  border-radius: var(--border-radius);
  text-align: center;
}

.ad-unit {
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Footer */
.footer {
  background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0;
  text-align: center;
  color: var(--text-secondary);
  margin-top: 4rem;
}

.footer p {
  margin-bottom: 1rem;
}

/* Utilities */
.more-link {
  display: inline-block;
  margin-top: 1rem;
  padding: 0.5rem 1rem;
  background-color: var(--primary-color);
  color: white;
  border-radius: var(--border-radius);
  font-weight: 500;
  transition: background-color 0.2s ease;
}

.more-link:hover {
  background-color: var(--secondary-color);
  color: white;
}

.empty-state {
  text-align: center;
  padding: 3rem;
  color: var(--text-secondary);
}

.back-to-archives {
  display: inline-block;
  margin-top: 2rem;
  padding: 0.5rem 1rem;
  background-color: var(--bg-secondary);
  color: var(--text-color);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
  font-weight: 500;
  transition: all 0.2s ease;
}

.back-to-archives:hover {
  background-color: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 0.5rem;
  }
  
  .header .container {
    flex-direction: column;
    gap: 1rem;
  }
  
  .nav-list {
    flex-direction: column;
    gap: 1rem;
  }
  
  .hero h1 {
    font-size: 2rem;
  }
  
  .article-grid {
    grid-template-columns: 1fr;
  }
  
  .article-nav {
    grid-template-columns: 1fr;
  }
  
  .card-meta {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }
  
  .archive-post {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.25rem;
  }
  
  .tags-cloud {
    justify-content: center;
  }
  
  /* Mobile sidebar layout */
  .article-layout {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  
  .article-sidebar {
    position: static;
    order: 2;
    margin-top: 2rem;
  }
  
  .sidebar-section {
    margin-bottom: 1.5rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 2rem 0;
  }
  
  .hero h1 {
    font-size: 1.75rem;
  }
  
  .hero p {
    font-size: 1rem;
  }
  
  .article-title {
    font-size: 2rem;
  }
  
  .category-title,
  .page-header h1 {
    font-size: 2rem;
  }
  
  .article-card {
    padding: 1rem;
  }
  
  .main {
    padding: 1rem 0;
  }
}

/* Light theme enforced - Dark mode disabled */