/* ==============================================
   RayPhoneAI Theme — Main CSS
   ============================================== */

@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@300;400;500;600;700;900&family=JetBrains+Mono:wght@400;600&display=swap');

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

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: var(--line-height-base);
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

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

img { max-width: 100%; height: auto; display: block; }
ul { list-style: none; }

/* ── Container ── */
.container {
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ── Skip Link ── */
.skip-link {
  position: absolute; top: -40px; left: 0;
  background: var(--color-primary); color: var(--color-bg);
  padding: 8px 16px; z-index: 9999; border-radius: 0 0 8px 0;
}
.skip-link:focus { top: 0; }

/* =============================================
   HEADER
   ============================================= */
#masthead {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-header-bg);
  border-bottom: 1px solid var(--color-header-border);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  height: 64px;
}

/* Logo */
.site-branding { display: flex; align-items: center; gap: 10px; }
.site-branding a { display: flex; align-items: center; gap: 10px; }
.site-logo-img { height: 32px; width: auto; }

.site-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text-heading);
  letter-spacing: -0.02em;
  line-height: 1;
}

.site-title span { color: var(--color-primary); }
.site-description { font-size: 0.7rem; color: var(--color-text-muted); margin-top: 2px; }

/* Nav */
.main-navigation { display: flex; align-items: center; gap: 4px; }
.main-navigation ul { display: flex; align-items: center; gap: 2px; }

.main-navigation a {
  display: block;
  padding: 6px 12px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-header-text);
  border-radius: 6px;
  transition: background var(--transition), color var(--transition);
}

.main-navigation a:hover,
.main-navigation .current-menu-item > a,
.main-navigation .current_page_item > a {
  color: var(--color-primary);
  background: rgba(0, 212, 255, 0.08);
}

/* Header right */
.header-right { display: flex; align-items: center; gap: 12px; }

/* Search toggle */
.header-search-btn {
  background: none; border: none;
  color: var(--color-text-muted);
  cursor: pointer; padding: 6px;
  border-radius: 6px; display: flex; align-items: center;
  transition: color var(--transition), background var(--transition);
}
.header-search-btn:hover { color: var(--color-primary); background: rgba(0,212,255,0.08); }
.header-search-btn svg { width: 18px; height: 18px; }

/* CTA Button */
.header-cta {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 18px;
  background: var(--color-btn-primary-bg);
  color: var(--color-btn-primary-text) !important;
  font-size: 0.82rem;
  font-weight: 700;
  border-radius: 20px;
  border: none; cursor: pointer;
  transition: opacity var(--transition), transform var(--transition), box-shadow var(--transition);
  box-shadow: 0 0 16px rgba(0,212,255,0.3);
}
.header-cta:hover {
  opacity: 0.9; transform: translateY(-1px);
  box-shadow: 0 4px 24px rgba(0,212,255,0.4);
}

/* Hamburger */
.menu-toggle {
  display: none;
  background: none; border: none;
  cursor: pointer; padding: 6px;
  color: var(--color-text);
}
.menu-toggle span { display: block; width: 22px; height: 2px; background: currentColor; margin: 4px 0; transition: var(--transition); }

/* ── Header Search Bar ── */
.header-search-bar {
  display: none;
  position: absolute; top: 64px; left: 0; right: 0;
  background: var(--color-bg-secondary);
  border-bottom: 1px solid var(--color-border);
  padding: 12px 20px;
  z-index: 99;
}
.header-search-bar.is-open { display: block; }
.header-search-bar form { display: flex; max-width: 600px; margin: 0 auto; }
.header-search-bar input {
  flex: 1; padding: 10px 16px;
  background: var(--color-bg-tertiary); border: 1px solid var(--color-border);
  border-right: none; border-radius: 8px 0 0 8px;
  color: var(--color-text); font-size: 0.9rem; font-family: inherit;
}
.header-search-bar input:focus { outline: none; border-color: var(--color-primary); }
.header-search-bar button {
  padding: 10px 18px;
  background: var(--color-primary); color: var(--color-bg);
  border: none; border-radius: 0 8px 8px 0; cursor: pointer;
  font-weight: 600;
}

/* =============================================
   HERO SECTION (Featured Post)
   ============================================= */
.hero-section { padding: var(--section-gap) 0 40px; }

.hero-featured-post {
  position: relative;
  border-radius: 20px;
  overflow: hidden;
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 460px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  box-shadow: var(--card-shadow);
  transition: box-shadow var(--transition), border-color var(--transition), transform var(--transition);
  text-decoration: none;
  color: inherit;
}
.hero-featured-post:hover {
  border-color: var(--card-border-hover);
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-3px);
}

.hero-featured-image {
  position: relative;
  overflow: hidden;
}
.hero-featured-image img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.6s ease;
}
.hero-featured-post:hover .hero-featured-image img { transform: scale(1.04); }

.hero-featured-image::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(to right, transparent 60%, var(--color-bg-secondary) 100%);
}

.hero-featured-content {
  padding: 40px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 16px;
}

.hero-tagline {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-primary);
  display: flex; align-items: center; gap: 6px;
}
.hero-tagline::before {
  content: '';
  display: block; width: 16px; height: 2px;
  background: var(--color-primary);
}

.hero-featured-content h2 {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--color-text-heading);
  line-height: 1.4;
  letter-spacing: -0.02em;
}

.hero-featured-content .excerpt {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.7;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.hero-meta {
  display: flex; align-items: center; gap: 14px;
  font-size: 0.78rem; color: var(--color-text-muted);
}
.hero-meta svg { width: 14px; height: 14px; flex-shrink: 0; }

.hero-read-more {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 11px 24px;
  background: var(--color-primary);
  color: var(--color-bg);
  font-size: 0.85rem; font-weight: 700;
  border-radius: 24px;
  width: fit-content;
  transition: opacity var(--transition), transform var(--transition);
}
.hero-read-more:hover { opacity: 0.85; transform: translateX(2px); color: var(--color-bg); }
.hero-read-more svg { width: 16px; height: 16px; }

/* Sub-featured grid */
.sub-featured-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--gap);
  margin-top: 28px;
}

.sub-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--card-radius);
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  text-decoration: none; color: inherit;
  display: flex; flex-direction: column;
}
.sub-card:hover {
  border-color: var(--card-border-hover);
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-4px);
}

.sub-card-image {
  aspect-ratio: 16/9;
  overflow: hidden;
}
.sub-card-image img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.sub-card:hover .sub-card-image img { transform: scale(1.06); }

.sub-card-body {
  padding: 14px 16px 16px;
  display: flex; flex-direction: column; gap: 8px;
  flex: 1;
}
.sub-card-body h3 {
  font-size: 0.85rem; font-weight: 600;
  color: var(--color-text-heading);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.sub-card-meta {
  margin-top: auto;
  display: flex; align-items: center; gap: 10px;
  font-size: 0.72rem; color: var(--color-text-muted);
}

/* =============================================
   CATEGORY FILTER TABS
   ============================================= */
.category-filter {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  padding: 0 0 32px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 40px;
}

.cat-tab {
  display: inline-flex; align-items: center;
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.8rem; font-weight: 600;
  border: 1.5px solid var(--color-border);
  color: var(--color-text-muted);
  background: transparent;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
}
.cat-tab:hover,
.cat-tab.active {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(0, 212, 255, 0.06);
}
.cat-tab.active { box-shadow: 0 0 12px rgba(0,212,255,0.15); }

/* =============================================
   CATEGORY BADGE
   ============================================= */
.cat-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 12px;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.5;
  text-transform: none;
}

/* Dynamic category colors */
.cat-badge[data-cat="ai-technology"],
.cat-badge.cat-ai-technology     { background: rgba(0,212,255,0.12); color: var(--cat-ai-technology); }
.cat-badge[data-cat="tool-reviews"],
.cat-badge.cat-tool-reviews      { background: rgba(124,92,252,0.12); color: var(--cat-tool-reviews); }
.cat-badge[data-cat="trend-analysis"],
.cat-badge.cat-trend-analysis    { background: rgba(255,107,107,0.12); color: var(--cat-trend-analysis); }
.cat-badge[data-cat="prompt-engineering"],
.cat-badge.cat-prompt-engineering{ background: rgba(245,158,11,0.12); color: var(--cat-prompt-engineering); }
.cat-badge[data-cat="writing-skills"],
.cat-badge.cat-writing-skills    { background: rgba(16,185,129,0.12); color: var(--cat-writing-skills); }
.cat-badge[data-cat="use-cases"],
.cat-badge.cat-use-cases         { background: rgba(236,72,153,0.12); color: var(--cat-use-cases); }
.cat-badge                       { background: rgba(107,114,128,0.12); color: var(--cat-default); }

/* =============================================
   MAIN LAYOUT
   ============================================= */
.main-content-area { padding: var(--section-gap) 0; }

.content-sidebar-layout {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: 48px;
  align-items: start;
}

/* =============================================
   ARTICLE GRID
   ============================================= */
.section-header {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 28px;
}
.section-title {
  font-size: 1.2rem; font-weight: 700;
  color: var(--color-text-heading);
  display: flex; align-items: center; gap: 10px;
}
.section-title::before {
  content: '';
  display: block; width: 4px; height: 22px;
  background: var(--color-primary);
  border-radius: 2px;
}
.see-all-link {
  font-size: 0.8rem; font-weight: 600;
  color: var(--color-text-muted);
  display: flex; align-items: center; gap: 4px;
  padding: 5px 12px; border-radius: 6px;
  border: 1px solid var(--color-border);
  transition: all var(--transition);
}
.see-all-link:hover { color: var(--color-primary); border-color: var(--color-primary); }
.see-all-link svg { width: 14px; height: 14px; }

/* Article Grid */
.article-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--gap);
}

/* Article Card */
.article-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--card-radius);
  overflow: hidden;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
  text-decoration: none; color: inherit;
  display: flex; flex-direction: column;
}
.article-card:hover {
  border-color: var(--card-border-hover);
  box-shadow: var(--card-shadow-hover);
  transform: translateY(-4px);
}

.article-card-image {
  aspect-ratio: 16/9;
  overflow: hidden;
  position: relative;
}
.article-card-image img {
  width: 100%; height: 100%;
  object-fit: cover;
  transition: transform 0.5s ease;
}
.article-card:hover .article-card-image img { transform: scale(1.05); }

/* No image fallback */
.article-card-image-placeholder {
  aspect-ratio: 16/9;
  display: flex; align-items: center; justify-content: center;
  background: var(--color-bg-tertiary);
  color: var(--color-text-muted);
  font-size: 2rem;
}

.article-card-body {
  padding: 18px 20px 20px;
  display: flex; flex-direction: column; gap: 10px;
  flex: 1;
}

.article-card-body h2,
.article-card-body h3 {
  font-size: 0.95rem; font-weight: 600;
  color: var(--color-text-heading);
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card-excerpt {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.article-card-meta {
  margin-top: auto;
  display: flex; align-items: center; justify-content: space-between;
  font-size: 0.75rem; color: var(--color-text-muted);
}
.article-card-meta-left { display: flex; align-items: center; gap: 10px; }
.article-card-meta svg { width: 13px; height: 13px; flex-shrink: 0; }

/* Tags */
.article-tags {
  display: flex; flex-wrap: wrap; gap: 6px;
}
.article-tag {
  font-size: 0.7rem;
  padding: 2px 8px;
  border-radius: 4px;
  background: rgba(255,255,255,0.04);
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  text-decoration: none;
  transition: all var(--transition);
}
.article-tag:hover { border-color: var(--color-primary); color: var(--color-primary); }
.article-tag::before { content: '#'; }

/* Pagination */
.pagination {
  display: flex; align-items: center; justify-content: center; gap: 6px;
  margin-top: 48px;
}
.pagination .page-numbers {
  display: inline-flex; align-items: center; justify-content: center;
  width: 38px; height: 38px;
  border-radius: 8px;
  background: var(--card-bg); border: 1px solid var(--color-border);
  color: var(--color-text-muted); font-size: 0.85rem;
  text-decoration: none;
  transition: all var(--transition);
}
.pagination .page-numbers:hover,
.pagination .page-numbers.current {
  background: var(--color-primary); border-color: var(--color-primary);
  color: var(--color-bg); font-weight: 700;
}
.pagination .page-numbers.dots { border: none; background: none; }

/* =============================================
   SIDEBAR
   ============================================= */
.sidebar { display: flex; flex-direction: column; gap: 32px; }

.widget {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: var(--card-radius);
  overflow: hidden;
}

.widget-header {
  padding: 16px 20px;
  border-bottom: 1px solid var(--color-border);
  display: flex; align-items: center; gap: 8px;
}
.widget-header h3 {
  font-size: 0.9rem; font-weight: 700;
  color: var(--color-text-heading);
  display: flex; align-items: center; gap: 8px;
}
.widget-header h3::before {
  content: '';
  display: block; width: 3px; height: 16px;
  background: var(--color-primary); border-radius: 2px;
}

.widget-body { padding: 16px 20px; }

/* Popular Posts */
.popular-post-list { display: flex; flex-direction: column; }

.popular-post-item {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none; color: inherit;
  transition: background var(--transition);
}
.popular-post-item:last-child { border-bottom: none; padding-bottom: 0; }
.popular-post-item:first-child { padding-top: 0; }
.popular-post-item:hover .popular-post-title { color: var(--color-primary); }

.popular-post-rank {
  font-size: 1.2rem; font-weight: 900;
  min-width: 24px; text-align: center;
  line-height: 1;
}
.popular-post-rank.rank-1 { color: #ffd700; }
.popular-post-rank.rank-2 { color: #c0c0c0; }
.popular-post-rank.rank-3 { color: #cd7f32; }
.popular-post-rank       { color: var(--color-text-muted); font-size: 0.9rem; }

.popular-post-thumb {
  width: 60px; height: 45px; border-radius: 6px;
  overflow: hidden; flex-shrink: 0;
}
.popular-post-thumb img { width: 100%; height: 100%; object-fit: cover; }

.popular-post-info { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 5px; }
.popular-post-title {
  font-size: 0.8rem; font-weight: 600;
  color: var(--color-text); line-height: 1.4;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  transition: color var(--transition);
}
.popular-post-meta { font-size: 0.7rem; color: var(--color-text-muted); }

/* Category Widget */
.category-list { display: flex; flex-direction: column; gap: 6px; }
.category-list-item a {
  display: flex; align-items: center; justify-content: space-between;
  padding: 9px 12px;
  border-radius: 8px;
  background: rgba(255,255,255,0.02);
  border: 1px solid var(--color-border);
  color: var(--color-text); font-size: 0.84rem;
  text-decoration: none;
  transition: all var(--transition);
}
.category-list-item a:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(0,212,255,0.04);
}
.cat-count {
  font-size: 0.72rem; font-weight: 600;
  background: var(--color-bg-tertiary);
  padding: 2px 7px; border-radius: 10px;
  color: var(--color-text-muted);
}

/* About widget */
.about-widget-content { text-align: center; }
.about-widget-logo { font-size: 1.5rem; font-weight: 900; color: var(--color-text-heading); margin-bottom: 8px; }
.about-widget-logo span { color: var(--color-primary); }
.about-widget-desc { font-size: 0.82rem; color: var(--color-text-muted); line-height: 1.6; }
.about-widget-tag {
  display: inline-block; margin-top: 12px;
  padding: 4px 14px; border-radius: 12px;
  background: rgba(0,212,255,0.1); color: var(--color-primary);
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.06em;
}

/* =============================================
   SINGLE POST
   ============================================= */
.single-post-layout {
  display: grid;
  grid-template-columns: 1fr var(--sidebar-width);
  gap: 48px;
  align-items: start;
}

.single-post-header {
  margin-bottom: 32px;
  display: flex; flex-direction: column; gap: 16px;
}

.single-post-title {
  font-size: 1.9rem; font-weight: 700;
  color: var(--color-text-heading);
  line-height: 1.35; letter-spacing: -0.02em;
}

.single-post-meta {
  display: flex; align-items: center; gap: 16px;
  font-size: 0.82rem; color: var(--color-text-muted);
  flex-wrap: wrap;
}
.single-post-meta svg { width: 14px; height: 14px; }
.single-post-meta-item { display: flex; align-items: center; gap: 6px; }

.single-post-eyecatch {
  border-radius: var(--card-radius); overflow: hidden;
  margin-bottom: 40px;
}
.single-post-eyecatch img { width: 100%; }

/* Article content */
.entry-content {
  font-size: 1rem; line-height: 1.9;
  color: var(--color-text);
}

.entry-content h2 {
  font-size: 1.45rem; font-weight: 700;
  color: var(--color-text-heading);
  margin: 2.5em 0 0.8em;
  padding-left: 16px;
  border-left: 4px solid var(--color-primary);
  line-height: 1.4;
}
.entry-content h3 {
  font-size: 1.2rem; font-weight: 700;
  color: var(--color-text-heading);
  margin: 2em 0 0.7em;
}
.entry-content h4 {
  font-size: 1rem; font-weight: 700;
  color: var(--color-text-heading);
  margin: 1.5em 0 0.5em;
}

.entry-content p { margin-bottom: 1.4em; }

.entry-content a { color: var(--color-primary); text-decoration: underline; text-decoration-color: rgba(0,212,255,0.3); }
.entry-content a:hover { text-decoration-color: var(--color-primary); }

.entry-content ul, .entry-content ol {
  margin: 1em 0 1.4em 1.5em;
}
.entry-content ul li { list-style: disc; margin-bottom: 0.4em; }
.entry-content ol li { list-style: decimal; margin-bottom: 0.4em; }

.entry-content blockquote {
  margin: 1.5em 0;
  padding: 16px 20px;
  border-left: 3px solid var(--color-secondary);
  background: rgba(124,92,252,0.06);
  border-radius: 0 8px 8px 0;
  color: var(--color-text-muted);
  font-style: italic;
}

.entry-content code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  padding: 2px 6px; border-radius: 4px;
  color: var(--color-primary);
}

.entry-content pre {
  background: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  border-radius: 8px; padding: 20px;
  overflow-x: auto; margin: 1.5em 0;
}
.entry-content pre code {
  background: none; border: none; padding: 0;
  font-size: 0.88rem; color: var(--color-text);
}

.entry-content img { border-radius: 8px; margin: 1.5em 0; }

.entry-content table {
  width: 100%; border-collapse: collapse; margin: 1.5em 0;
  font-size: 0.9rem;
}
.entry-content th {
  background: var(--color-bg-tertiary);
  padding: 10px 14px; text-align: left;
  border: 1px solid var(--color-border);
  color: var(--color-text-heading); font-weight: 600;
}
.entry-content td {
  padding: 10px 14px;
  border: 1px solid var(--color-border);
}
.entry-content tr:nth-child(even) td { background: rgba(255,255,255,0.02); }

/* Post footer */
.single-post-footer { margin-top: 48px; display: flex; flex-direction: column; gap: 32px; }

.post-tags-section h4 {
  font-size: 0.85rem; color: var(--color-text-muted);
  margin-bottom: 10px; font-weight: 600;
}
.post-tags-wrap { display: flex; flex-wrap: wrap; gap: 6px; }

/* Share buttons */
.share-section h4 { font-size: 0.85rem; color: var(--color-text-muted); margin-bottom: 10px; font-weight: 600; }
.share-buttons { display: flex; gap: 10px; flex-wrap: wrap; }
.share-btn {
  display: inline-flex; align-items: center; gap: 7px;
  padding: 9px 18px; border-radius: 8px;
  font-size: 0.82rem; font-weight: 600;
  cursor: pointer; text-decoration: none;
  transition: opacity var(--transition);
}
.share-btn:hover { opacity: 0.85; }
.share-btn.twitter  { background: #1d9bf0; color: #fff; }
.share-btn.facebook { background: #1877f2; color: #fff; }
.share-btn.copy-url { background: var(--card-bg); border: 1px solid var(--color-border); color: var(--color-text); }
.share-btn svg { width: 16px; height: 16px; }

/* Related posts */
.related-posts-section h3 {
  font-size: 1.1rem; font-weight: 700;
  color: var(--color-text-heading);
  margin-bottom: 20px;
  display: flex; align-items: center; gap: 8px;
}
.related-posts-section h3::before {
  content: ''; display: block; width: 3px; height: 18px;
  background: var(--color-primary); border-radius: 2px;
}
.related-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 16px; }

/* TOC (Table of Contents) */
.toc-widget {
  background: var(--card-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--card-radius);
  overflow: hidden;
  position: sticky; top: 80px;
}
.toc-header {
  padding: 14px 18px;
  border-bottom: 1px solid var(--color-border);
  font-size: 0.85rem; font-weight: 700; color: var(--color-text-heading);
  display: flex; align-items: center; gap: 8px;
}
.toc-header::before { content: ''; display: block; width: 3px; height: 14px; background: var(--color-primary); border-radius: 2px; }
.toc-list { padding: 12px 18px; display: flex; flex-direction: column; gap: 4px; list-style: none; }
.toc-item a {
  display: block; padding: 5px 8px; border-radius: 5px;
  font-size: 0.8rem; color: var(--color-text-muted); text-decoration: none;
  transition: all var(--transition); border-left: 2px solid transparent;
}
.toc-item a:hover, .toc-item.active a {
  color: var(--color-primary); background: rgba(0,212,255,0.04);
  border-left-color: var(--color-primary); padding-left: 12px;
}
.toc-item.depth-3 a { padding-left: 20px; font-size: 0.75rem; }
.toc-item.depth-3.active a { padding-left: 24px; }

/* =============================================
   ARCHIVE / CATEGORY PAGE
   ============================================= */
.archive-header {
  padding: 48px 0 36px;
  border-bottom: 1px solid var(--color-border);
  margin-bottom: 48px;
}
.archive-label {
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--color-primary);
  margin-bottom: 8px;
}
.archive-title {
  font-size: 2rem; font-weight: 700;
  color: var(--color-text-heading); letter-spacing: -0.02em;
}
.archive-desc { font-size: 0.9rem; color: var(--color-text-muted); margin-top: 8px; }
.archive-count { font-size: 0.8rem; color: var(--color-text-muted); margin-top: 4px; }

/* =============================================
   FOOTER
   ============================================= */
#colophon {
  background: var(--color-bg-tertiary);
  border-top: 1px solid var(--color-border);
  margin-top: var(--section-gap);
}

.footer-main {
  display: grid;
  grid-template-columns: 280px 1fr 1fr;
  gap: 48px;
  padding: 48px 0;
  border-bottom: 1px solid var(--color-border);
}

.footer-brand .footer-logo {
  font-size: 1.3rem; font-weight: 900;
  color: var(--color-text-heading); margin-bottom: 10px;
}
.footer-brand .footer-logo span { color: var(--color-primary); }
.footer-brand p { font-size: 0.82rem; color: var(--color-text-muted); line-height: 1.7; }
.footer-powered {
  display: inline-block; margin-top: 12px;
  padding: 3px 12px; border-radius: 10px;
  background: rgba(0,212,255,0.08); color: var(--color-primary);
  font-size: 0.7rem; font-weight: 600; letter-spacing: 0.06em;
}

.footer-widget-title {
  font-size: 0.88rem; font-weight: 700;
  color: var(--color-text-heading); margin-bottom: 14px;
  padding-bottom: 8px; border-bottom: 1px solid var(--color-border);
}

.footer-links { display: flex; flex-direction: column; gap: 8px; }
.footer-links li a {
  font-size: 0.82rem; color: var(--color-text-muted);
  text-decoration: none; display: flex; align-items: center; gap: 6px;
  transition: color var(--transition);
}
.footer-links li a::before {
  content: '▸'; font-size: 0.6rem; color: var(--color-primary);
}
.footer-links li a:hover { color: var(--color-primary); }

.footer-bottom {
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 0;
  font-size: 0.78rem; color: var(--color-text-muted);
  gap: 12px; flex-wrap: wrap;
}
.footer-bottom-links { display: flex; gap: 16px; }
.footer-bottom-links a { color: var(--color-text-muted); text-decoration: none; transition: color var(--transition); }
.footer-bottom-links a:hover { color: var(--color-primary); }

/* =============================================
   BREADCRUMBS
   ============================================= */
.breadcrumbs {
  display: flex; align-items: center; gap: 6px; flex-wrap: wrap;
  padding: 14px 0;
  font-size: 0.78rem; color: var(--color-text-muted);
}
.breadcrumbs a { color: var(--color-text-muted); text-decoration: none; transition: color var(--transition); }
.breadcrumbs a:hover { color: var(--color-primary); }
.breadcrumb-sep { color: var(--color-border); }
.breadcrumb-current { color: var(--color-text); }

/* =============================================
   404 & Search
   ============================================= */
.error-page, .no-results-page {
  text-align: center; padding: 80px 20px;
}
.error-code {
  font-size: 8rem; font-weight: 900;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  line-height: 1; margin-bottom: 16px;
}
.error-title { font-size: 1.5rem; font-weight: 700; color: var(--color-text-heading); margin-bottom: 8px; }
.error-desc { color: var(--color-text-muted); margin-bottom: 28px; }
.btn-back-home {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 28px; background: var(--color-primary);
  color: var(--color-bg); font-weight: 700; border-radius: 24px;
  text-decoration: none; transition: opacity var(--transition);
}
.btn-back-home:hover { opacity: 0.85; color: var(--color-bg); }

.search-results-header { margin-bottom: 32px; }
.search-results-header h1 { font-size: 1.5rem; font-weight: 700; color: var(--color-text-heading); }
.search-query { color: var(--color-primary); }

/* =============================================
   UTILITY
   ============================================= */
.glow-text {
  text-shadow: 0 0 20px rgba(0, 212, 255, 0.4);
}
.visually-hidden {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* Loading skeleton */
.skeleton {
  background: linear-gradient(90deg, var(--color-bg-secondary) 25%, var(--color-bg-tertiary) 50%, var(--color-bg-secondary) 75%);
  background-size: 200% 100%;
  animation: skeleton-shimmer 1.5s infinite;
  border-radius: 4px;
}
@keyframes skeleton-shimmer { to { background-position: -200% 0; } }

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 1100px) {
  .content-sidebar-layout,
  .single-post-layout {
    grid-template-columns: 1fr;
  }
  .sidebar { flex-direction: row; flex-wrap: wrap; }
  .sidebar .widget { flex: 1; min-width: 260px; }
  .sub-featured-grid { grid-template-columns: repeat(2,1fr); }
}

@media (max-width: 768px) {
  :root {
    --section-gap: 40px;
    --gap: 16px;
  }

  .main-navigation { display: none; position: fixed; top: 64px; left: 0; right: 0; bottom: 0; background: var(--color-bg-secondary); flex-direction: column; align-items: flex-start; padding: 20px; overflow-y: auto; z-index: 98; }
  .main-navigation.is-open { display: flex; }
  .main-navigation ul { flex-direction: column; width: 100%; }
  .main-navigation a { font-size: 1rem; padding: 12px 16px; }

  .menu-toggle { display: block; }
  .header-cta span { display: none; }

  .hero-featured-post { grid-template-columns: 1fr; }
  .hero-featured-image { min-height: 240px; }
  .hero-featured-image::after { background: linear-gradient(to bottom, transparent 50%, var(--color-bg-secondary) 100%); }
  .hero-featured-content { padding: 24px; }
  .hero-featured-content h2 { font-size: 1.3rem; }

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

  .article-grid { grid-template-columns: 1fr; }

  .related-grid { grid-template-columns: 1fr 1fr; }

  .footer-main { grid-template-columns: 1fr; gap: 28px; padding: 32px 0; }

  .single-post-title { font-size: 1.5rem; }

  .sidebar { flex-direction: column; }

  .footer-bottom { flex-direction: column; align-items: flex-start; gap: 8px; }
}

@media (max-width: 480px) {
  .sub-featured-grid { grid-template-columns: 1fr; }
  .related-grid { grid-template-columns: 1fr; }
  .error-code { font-size: 5rem; }
}