/* ========================================
   Knowledge Basement - SEO & Design Refresh
   Loaded after style.css as a focused override layer.
   ======================================== */

:root {
  --color-primary: #1d4ed8;
  --color-primary-hover: #1e40af;
  --color-primary-light: #60a5fa;
  --color-secondary: #0f766e;
  --color-accent: #f97316;
  --color-text: #0f172a;
  --color-text-light: #475569;
  --color-text-lighter: #64748b;
  --color-bg: #ffffff;
  --color-bg-secondary: #f8fafc;
  --color-bg-tertiary: #eef2ff;
  --color-bg-dark: #0f172a;
  --color-border: #dbe4ef;
  --color-border-light: #edf2f7;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 10px 25px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 18px 45px rgba(15, 23, 42, 0.12);
  --shadow-xl: 0 28px 70px rgba(15, 23, 42, 0.18);
}

body {
  background:
    radial-gradient(circle at top left, rgba(96, 165, 250, 0.12), transparent 28rem),
    linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
}

a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: var(--spacing-sm);
  left: var(--spacing-sm);
  z-index: 2000;
  padding: 0.75rem 1rem;
  background: var(--color-bg-dark);
  color: white;
  border-radius: var(--radius-md);
  transform: translateY(-150%);
  transition: transform var(--transition-fast);
}

.skip-link:focus {
  transform: translateY(0);
}

.container {
  max-width: 1180px;
}

.container-narrow {
  max-width: 860px;
}

.site-header {
  padding: 0.875rem 0;
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid rgba(219, 228, 239, 0.8);
  box-shadow: 0 8px 30px rgba(15, 23, 42, 0.06);
}

.site-title {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--color-text);
}

.brand-mark {
  display: inline-grid;
  place-items: center;
  width: 2.5rem;
  height: 2.5rem;
  border-radius: 0.8rem;
  background: linear-gradient(135deg, var(--color-primary), #7c3aed);
  color: white;
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  box-shadow: var(--shadow-md);
}

.site-title-text,
.footer-title {
  font-weight: 800;
  letter-spacing: -0.02em;
}

.site-tagline {
  margin-left: 3.25rem;
  max-width: 32rem;
}

.main-nav {
  gap: 0.5rem;
}

.nav-link,
.search-toggle {
  min-height: 2.5rem;
}

.nav-link {
  color: var(--color-text-light);
}

.nav-link:hover,
.nav-link.active {
  background: #eff6ff;
  color: var(--color-primary);
}

.search-toggle {
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  background: white;
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
}

.search-toggle:hover {
  border-color: var(--color-primary-light);
  background: #eff6ff;
}

.kbd-hint {
  padding: 0.1rem 0.35rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-secondary);
  color: var(--color-text-light);
  font-size: 0.75rem;
}

.hero-section {
  position: relative;
  overflow: hidden;
  padding: clamp(4rem, 8vw, 7rem) 0;
  background:
    radial-gradient(circle at 15% 20%, rgba(96, 165, 250, 0.35), transparent 18rem),
    radial-gradient(circle at 85% 10%, rgba(124, 58, 237, 0.25), transparent 20rem),
    linear-gradient(135deg, #0f172a 0%, #1d4ed8 55%, #312e81 100%);
  text-align: left;
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(280px, 0.75fr);
  gap: clamp(2rem, 5vw, 5rem);
  align-items: center;
}

.hero-content {
  max-width: none;
}

.eyebrow {
  color: var(--color-primary);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 0.75rem;
}

.hero-section .eyebrow {
  color: #bfdbfe;
}

.hero-title {
  max-width: 820px;
  font-size: clamp(2.5rem, 6vw, 5rem);
  letter-spacing: -0.055em;
  line-height: 0.98;
  text-shadow: none;
}

.hero-description {
  max-width: 720px;
  color: rgba(255, 255, 255, 0.86);
}

.hero-actions,
.section-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

.hero-card {
  padding: var(--spacing-lg);
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-xl);
  background: rgba(255, 255, 255, 0.12);
  color: white;
  box-shadow: var(--shadow-xl);
  backdrop-filter: blur(18px);
}

.hero-card h2 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-md);
}

.topic-chip-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.topic-chip,
.topic-strip a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  font-weight: 700;
  border-radius: var(--radius-full);
}

.topic-chip {
  padding: 0.65rem 0.85rem;
  background: rgba(255, 255, 255, 0.16);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.2);
}

.topic-chip:hover {
  background: rgba(255, 255, 255, 0.26);
}

.topic-chip span {
  display: inline-grid;
  place-items: center;
  min-width: 1.5rem;
  height: 1.5rem;
  padding: 0 0.4rem;
  border-radius: var(--radius-full);
  background: white;
  color: var(--color-primary);
  font-size: 0.78rem;
}

.hero-stats {
  justify-content: flex-start;
  gap: var(--spacing-lg);
  margin-top: var(--spacing-xl);
}

.stat-item {
  min-width: 8rem;
  align-items: flex-start;
  padding: 1rem 1.25rem;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.1);
}

.topic-strip {
  margin-top: -1.5rem;
  position: relative;
  z-index: 2;
}

.topic-strip-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  background: white;
  box-shadow: var(--shadow-md);
}

.topic-strip span {
  color: var(--color-text-light);
  font-weight: 700;
}

.topic-strip a {
  padding: 0.4rem 0.7rem;
  background: #eff6ff;
  color: var(--color-primary);
}

.section-header {
  max-width: 700px;
  margin-bottom: var(--spacing-xl);
}

.section-heading {
  margin-bottom: 0.5rem;
  font-size: clamp(2rem, 4vw, 3rem);
  letter-spacing: -0.04em;
}

.section-description,
.page-description {
  color: var(--color-text-light);
  font-size: 1.1rem;
  line-height: 1.7;
}

.posts-grid {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr));
}

.post-card {
  position: relative;
  overflow: hidden;
  border-color: rgba(219, 228, 239, 0.9);
  border-radius: var(--radius-xl);
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow-sm);
}

.post-card::before {
  content: '';
  position: absolute;
  inset: 0 0 auto;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), #7c3aed, var(--color-accent));
  opacity: 0;
  transition: opacity var(--transition-base);
}

.post-card:hover::before {
  opacity: 1;
}

.post-card-title {
  letter-spacing: -0.02em;
}

.post-card-title a::after {
  content: '';
  position: absolute;
  inset: 0;
}

.post-card-header,
.post-card-footer {
  position: relative;
  z-index: 1;
}

.post-card-footer {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.8rem;
  color: var(--color-text-lighter);
  font-size: 0.875rem;
}

.read-more {
  margin-left: auto;
  color: var(--color-primary);
  font-weight: 700;
}

.category-badge {
  background: #dbeafe;
  color: #1e40af;
  text-decoration: none;
}

.category-badge:hover {
  background: var(--color-primary);
  color: white;
}

.cta-button {
  border-radius: var(--radius-full);
}

.hero-section .cta-button.primary {
  background: white;
  color: var(--color-primary);
}

.hero-section .cta-button.secondary {
  background: rgba(255, 255, 255, 0.1);
  color: white;
  border-color: rgba(255, 255, 255, 0.35);
}

.page-hero {
  padding: var(--spacing-3xl) 0 var(--spacing-2xl);
  background:
    radial-gradient(circle at top right, rgba(96, 165, 250, 0.2), transparent 22rem),
    linear-gradient(180deg, #eff6ff 0%, rgba(255, 255, 255, 0) 100%);
  text-align: center;
}

.topics-hero .breadcrumb {
  justify-content: center;
  margin-bottom: var(--spacing-md);
}

.topic-archive-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
  gap: var(--spacing-lg);
}

.topic-archive-card {
  display: flex;
  min-height: 13rem;
  flex-direction: column;
  justify-content: space-between;
  padding: var(--spacing-lg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  background: white;
  color: var(--color-text);
  text-decoration: none;
  box-shadow: var(--shadow-sm);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

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

.topic-archive-card h2 {
  font-size: 1.5rem;
  letter-spacing: -0.03em;
}

.topic-archive-card p {
  color: var(--color-text-light);
}

.topic-archive-count {
  align-self: flex-start;
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius-full);
  background: #eff6ff;
  color: var(--color-primary);
  font-size: 0.8rem;
  font-weight: 800;
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  color: var(--color-text-lighter);
  font-size: 0.9rem;
}

.breadcrumb a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 700;
}

.post {
  padding: 0 0 var(--spacing-3xl);
}

.post-header {
  margin-bottom: var(--spacing-2xl);
  padding: var(--spacing-3xl) 0 var(--spacing-2xl);
  border-bottom: 0;
  background:
    radial-gradient(circle at top left, rgba(96, 165, 250, 0.18), transparent 22rem),
    linear-gradient(180deg, #eff6ff 0%, #ffffff 100%);
  text-align: left;
}

.post-header .post-categories {
  margin: var(--spacing-lg) 0 var(--spacing-sm);
}

.post-title {
  max-width: 900px;
  margin-bottom: var(--spacing-md);
  font-size: clamp(2.25rem, 5vw, 4rem);
  letter-spacing: -0.055em;
}

.post-description {
  max-width: 760px;
  color: var(--color-text-light);
  font-size: 1.2rem;
  line-height: 1.75;
  margin-bottom: var(--spacing-lg);
}

.post-meta-detailed {
  justify-content: flex-start;
  gap: 0.75rem;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: var(--spacing-md);
}

.post-tags span {
  color: var(--color-text-light);
  font-size: 0.85rem;
}

.post-content {
  padding: var(--spacing-xl);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-xl);
  background: white;
  box-shadow: var(--shadow-sm);
}

.post-content h2,
.post-content h3 {
  letter-spacing: -0.03em;
}

.post-content h2 {
  padding-top: var(--spacing-sm);
  border-top: 1px solid var(--color-border-light);
}

.post-content h2:first-child {
  border-top: 0;
  padding-top: 0;
  margin-top: 0;
}

.post-content blockquote {
  margin: var(--spacing-lg) 0;
  padding: var(--spacing-md) var(--spacing-lg);
  border-left: 4px solid var(--color-primary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: var(--color-bg-secondary);
  color: var(--color-text-light);
}

.post-content table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--spacing-lg) 0;
  display: block;
  overflow-x: auto;
}

.post-content th,
.post-content td {
  padding: 0.75rem;
  border: 1px solid var(--color-border);
}

.post-content th {
  background: var(--color-bg-secondary);
}

.post-footer {
  margin-top: var(--spacing-xl);
}

.post-share,
.related-posts {
  padding: var(--spacing-xl);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  background: white;
  box-shadow: var(--shadow-sm);
}

.post-share h2,
.related-posts h2 {
  font-size: 1.3rem;
  margin-bottom: var(--spacing-md);
}

.share-buttons,
.related-posts-grid {
  display: grid;
  gap: var(--spacing-sm);
}

.share-buttons {
  grid-template-columns: repeat(auto-fit, minmax(140px, max-content));
}

.share-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1rem;
  border-radius: var(--radius-full);
  background: #eff6ff;
  color: var(--color-primary);
  font-weight: 800;
  text-decoration: none;
}

.share-btn:hover {
  background: var(--color-primary);
  color: white;
}

.related-posts {
  margin-top: var(--spacing-lg);
}

.related-posts-grid {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
}

.related-post-card {
  display: flex;
  min-height: 8rem;
  flex-direction: column;
  justify-content: space-between;
  padding: var(--spacing-md);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  background: var(--color-bg-secondary);
  color: var(--color-text);
  text-decoration: none;
  transition: transform var(--transition-fast), border-color var(--transition-fast), background var(--transition-fast);
}

.related-post-card:hover {
  transform: translateY(-2px);
  border-color: var(--color-primary-light);
  background: white;
}

.related-post-title {
  font-weight: 800;
  line-height: 1.4;
}

.related-post-date {
  color: var(--color-text-light);
  font-size: 0.85rem;
}

.search-overlay {
  background: rgba(15, 23, 42, 0.72);
}

.search-container {
  max-width: 760px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-xl);
}

.search-header {
  justify-content: space-between;
  align-items: flex-start;
  padding: var(--spacing-lg) var(--spacing-lg) var(--spacing-sm);
  border-bottom: 0;
}

.search-heading h2 {
  font-size: 1.35rem;
  margin-bottom: 0.25rem;
}

.search-heading p {
  color: var(--color-text-light);
  font-size: 0.95rem;
}

.search-input {
  width: calc(100% - 2 * var(--spacing-lg));
  margin: 0 var(--spacing-lg) var(--spacing-md);
  padding: 0.9rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg-secondary);
}

.footer-title {
  display: inline-flex;
  color: white;
  text-decoration: none;
  font-size: 1.2rem;
  margin-bottom: var(--spacing-sm);
}

.footer-section a span {
  color: rgba(255, 255, 255, 0.55);
}

@media (max-width: 900px) {
  .header-content,
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .header-content {
    flex-direction: column;
    align-items: flex-start;
  }

  .main-nav {
    width: 100%;
    overflow-x: auto;
    padding-bottom: 0.25rem;
  }

  .hero-card {
    max-width: 640px;
  }
}

@media (max-width: 640px) {
  .site-tagline,
  .kbd-hint,
  .search-toggle-label {
    display: none;
  }

  .main-nav {
    gap: 0.35rem;
  }

  .nav-link,
  .search-toggle {
    padding: 0.5rem 0.65rem;
  }

  .hero-section,
  .page-hero,
  .post-header {
    padding-top: var(--spacing-2xl);
    padding-bottom: var(--spacing-2xl);
  }

  .hero-stats,
  .hero-actions,
  .section-cta {
    flex-direction: column;
    align-items: stretch;
  }

  .stat-item {
    min-width: 0;
  }

  .post-content,
  .post-share,
  .related-posts {
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
  }

  .post-meta-detailed .meta-separator {
    display: none;
  }

  .read-more {
    flex-basis: 100%;
    margin-left: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .skip-link,
  .post-card::before,
  .topic-archive-card,
  .related-post-card {
    transition: none !important;
  }
}