/* =============================================================================
   Deneb Blog — Main Stylesheet
   Design tokens, resets, components, and responsive layout.
   ============================================================================= */

/* === Design Tokens === */
:root {
  /* Colours */
  --bg-primary: #0f1115;
  --bg-primary-rgb: 15, 17, 21;
  --bg-secondary: #161a21;
  --text-primary: #e6e8eb;
  --text-secondary: #9aa3ad;
  --accent: #4cc2ff;
  --border-subtle: #232831;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 32px;
  --space-xl: 64px;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;

  /* Shadows */
  --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.2);
  --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.35);

  /* Typography */
  --font-display: 'Space Grotesk', system-ui, -apple-system, sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;

  --text-h1: clamp(2.2rem, 4vw, 2.8rem);
  --text-h2: clamp(1.6rem, 3vw, 2rem);
  --text-h3: clamp(1.2rem, 2vw, 1.4rem);
  --text-body: 1rem;
  --text-meta: 0.875rem;

  --line-height-heading: 1.25;
  --line-height-body: 1.7;
}

/* Light theme overrides */
[data-theme="light"] {
  --bg-primary: #f8f9fb;
  --bg-primary-rgb: 248, 249, 251;
  --bg-secondary: #eef0f3;
  --text-primary: #1a1d23;
  --text-secondary: #5a6370;
  --accent: #0068b5; /* Darker blue for sufficient contrast on light backgrounds (WCAG AA) */
  --border-subtle: #dde0e6;
  --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.14);
}

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

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: var(--text-body);
  line-height: var(--line-height-body);
  transition: background-color 0.2s ease, color 0.2s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

/* === Skip Link === */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  background: var(--accent);
  color: #0f1115;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  font-weight: 500;
  text-decoration: none;
  z-index: 9999;
  transition: top 0.1s ease;
  white-space: nowrap;
}

.skip-link:focus {
  top: var(--space-md);
}

/* === Header / Navigation === */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  /* Slightly transparent for frosted-glass effect */
  background-color: rgba(15, 17, 21, 0.95);
  border-bottom: 1px solid var(--border-subtle);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: background-color 0.2s ease;
}

[data-theme="light"] .site-header {
  background-color: rgba(248, 249, 251, 0.95);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-md) var(--space-lg);
  display: flex;
  align-items: center;
  gap: var(--space-lg);
}

.nav-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.02em;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.nav-logo .logo-star {
  color: var(--accent);
}

.nav-links {
  list-style: none;
  display: flex;
  gap: var(--space-lg);
  flex: 1;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: var(--text-meta);
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: uppercase;
  transition: color 0.15s ease;
}

.nav-links a:hover,
.nav-links a[aria-current="page"] {
  color: var(--accent);
}

.nav-links a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  padding: 6px 10px;
  font-size: 1rem;
  line-height: 1;
  transition: border-color 0.15s ease, color 0.15s ease;
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.theme-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.theme-label {
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

/* Mobile nav */
@media (max-width: 480px) {
  .nav-container {
    padding: var(--space-md);
    gap: var(--space-md);
  }

  .theme-label {
    display: none;
  }
}

/* === Hero Section === */
.hero {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: var(--space-xl);
  align-items: center;
  min-height: 55vh;
}

@media (max-width: 768px) {
  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
    padding: var(--space-lg) var(--space-md);
  }

  .hero-visual {
    display: none;
  }
}

.hero-eyebrow {
  color: var(--accent);
  font-size: var(--text-meta);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-sm);
}

.hero-heading {
  font-family: var(--font-display);
  font-size: var(--text-h1);
  font-weight: 700;
  line-height: var(--line-height-heading);
  letter-spacing: -0.03em;
  margin-bottom: var(--space-md);
}

.hero-heading a {
  color: var(--text-primary);
  text-decoration: none;
  transition: color 0.15s ease;
}

.hero-heading a:hover {
  color: var(--accent);
}

.hero-heading a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.hero-description {
  color: var(--text-secondary);
  font-size: 1.125rem;
  line-height: var(--line-height-body);
  max-width: 55ch;
  margin-bottom: var(--space-md);
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-size: var(--text-meta);
  margin-bottom: var(--space-lg);
}

/* Hero visual accent — intentional asymmetric element */
.hero-visual {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
}

.star-ring {
  width: 220px;
  height: 220px;
  border-radius: 50%;
  border: 1px solid var(--border-subtle);
  position: relative;
  background: radial-gradient(ellipse at center, rgba(76, 194, 255, 0.06) 0%, transparent 70%);
}

.star-ring::before {
  content: '';
  position: absolute;
  inset: 20px;
  border-radius: 50%;
  border: 1px solid rgba(76, 194, 255, 0.12);
}

.star-ring::after {
  content: '✦';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: var(--accent);
  font-size: 2.5rem;
  opacity: 0.65;
}

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 10px var(--space-lg);
  border-radius: var(--radius-sm);
  font-weight: 500;
  font-size: var(--text-meta);
  text-decoration: none;
  transition: all 0.15s ease;
  letter-spacing: 0.01em;
  border: none;
  cursor: pointer;
}

.btn-primary {
  background-color: var(--accent);
  color: #0f1115;
}

.btn-primary:hover {
  opacity: 0.88;
  transform: translateY(-1px);
  box-shadow: 0 4px 14px rgba(76, 194, 255, 0.32);
}

.btn-primary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* === AI Badge === */
.ai-badge {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--accent);
  border: 1px solid rgba(76, 194, 255, 0.3);
  border-radius: var(--radius-sm);
  padding: 2px 8px;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.ai-badge::before {
  content: '◈';
  font-size: 0.65rem;
}

/* === Posts Section === */
.posts-section {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
  border-top: 1px solid var(--border-subtle);
}

@media (max-width: 768px) {
  .posts-section {
    padding: var(--space-lg) var(--space-md);
  }
}

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: var(--space-xl);
  gap: var(--space-md);
}

.section-heading {
  font-family: var(--font-display);
  font-size: var(--text-h2);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: var(--line-height-heading);
}

.posts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-lg);
}

/* === Post Card === */
.post-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.post-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-hover);
  border-color: rgba(76, 194, 255, 0.25);
}

/* Featured card spans wider on large screens — the intentional layout break */
.post-card--featured {
  grid-column: span 1;
}

@media (min-width: 900px) {
  .post-card--featured {
    grid-column: span 2;
  }
}

.post-card__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-size: var(--text-meta);
}

.post-card__title {
  font-family: var(--font-display);
  font-size: var(--text-h3);
  font-weight: 700;
  line-height: var(--line-height-heading);
  letter-spacing: -0.02em;
}

.post-card__title a {
  color: var(--text-primary);
  text-decoration: none;
  transition: color 0.15s ease;
}

.post-card__title a:hover {
  color: var(--accent);
}

.post-card__title a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.post-card__description {
  color: var(--text-secondary);
  font-size: var(--text-body);
  line-height: var(--line-height-body);
  flex: 1;
}

.post-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.post-card__tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
}

.tag {
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 2px 8px;
  letter-spacing: 0.02em;
}

/* === Footer === */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  margin-top: var(--space-xl);
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: var(--space-xl);
  align-items: start;
}

@media (max-width: 600px) {
  .footer-container {
    grid-template-columns: 1fr;
    gap: var(--space-lg);
    padding: var(--space-lg) var(--space-md);
  }
}

.footer-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-sm);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.footer-logo .logo-star {
  color: var(--accent);
}

.footer-disclaimer {
  color: var(--text-secondary);
  font-size: var(--text-meta);
  line-height: 1.65;
  max-width: 52ch;
  font-style: italic;
}

.footer-nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.footer-nav-heading {
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
}

.footer-nav a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: var(--text-meta);
  font-weight: 500;
  transition: color 0.15s ease;
}

.footer-nav a:hover {
  color: var(--accent);
}

.footer-nav a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.footer-bottom {
  grid-column: 1 / -1;
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  font-size: 0.75rem;
  opacity: 0.75;
}

/* === Article Page === */
.article-page {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

@media (max-width: 768px) {
  .article-page {
    padding: var(--space-lg) var(--space-md);
  }
}

.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-size: var(--text-meta);
  margin-bottom: var(--space-lg);
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.15s ease;
}

.breadcrumb a:hover {
  color: var(--accent);
}

.breadcrumb a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.article-header {
  margin-bottom: var(--space-xl);
}

.article-title {
  font-family: var(--font-display);
  font-size: var(--text-h1);
  font-weight: 700;
  line-height: var(--line-height-heading);
  letter-spacing: -0.03em;
  margin-bottom: var(--space-md);
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  color: var(--text-secondary);
  font-size: var(--text-meta);
  padding: var(--space-md) 0;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.article-body {
  margin-top: var(--space-xl);
}

.article-body h2 {
  font-family: var(--font-display);
  font-size: var(--text-h2);
  font-weight: 700;
  line-height: var(--line-height-heading);
  letter-spacing: -0.02em;
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}

.article-body h3 {
  font-family: var(--font-display);
  font-size: var(--text-h3);
  font-weight: 600;
  margin-top: var(--space-lg);
  margin-bottom: var(--space-sm);
}

.article-body p {
  margin-bottom: var(--space-md);
  line-height: var(--line-height-body);
  color: var(--text-primary);
}

.article-body a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.article-body a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

.article-body ul,
.article-body ol {
  margin: var(--space-md) 0 var(--space-md) var(--space-lg);
  line-height: var(--line-height-body);
}

.article-body li {
  margin-bottom: var(--space-xs);
}

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

/* AI Insight Callout */
.ai-callout {
  border-left: 3px solid var(--accent);
  background-color: var(--bg-secondary);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-lg) 0;
}

.ai-callout__label {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  color: var(--accent);
  font-size: var(--text-meta);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: var(--space-sm);
}

.ai-callout__label::before {
  content: '◈';
}

.ai-callout p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  margin-bottom: 0;
  line-height: 1.65;
}

.ai-callout .confidence {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: var(--space-sm);
  font-size: 0.75rem;
  color: var(--text-secondary);
  opacity: 0.8;
}

/* Wardley map figure */
.wardley-map {
  margin: var(--space-lg) 0;
  padding: var(--space-md);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  background: var(--bg-secondary);
}

.wardley-map svg {
  width: 100%;
  height: auto;
  display: block;
}

.wardley-map__surface {
  fill: rgba(var(--bg-primary-rgb), 0.35);
  stroke: var(--border-subtle);
}

.wardley-map__axis {
  stroke: var(--text-secondary);
  stroke-width: 1.5;
}

.wardley-map__grid {
  stroke: var(--border-subtle);
  stroke-width: 1;
  stroke-dasharray: 3 5;
}

.wardley-map__stage-label,
.wardley-map__axis-label,
.wardley-map__node-label,
.wardley-map__key-label {
  fill: var(--text-secondary);
  font-family: var(--font-body);
}

.wardley-map__stage-label,
.wardley-map__axis-label,
.wardley-map__key-label {
  font-size: 13px;
}

.wardley-map__node-label {
  font-size: 14px;
  fill: var(--text-primary);
}

.wardley-map__link {
  stroke: rgba(76, 194, 255, 0.45);
  stroke-width: 1.75;
}

.wardley-map__node {
  stroke-width: 1.5;
}

.wardley-map__node--emergent {
  fill: rgba(76, 194, 255, 0.18);
  stroke: var(--accent);
}

.wardley-map__node--middle {
  fill: rgba(154, 163, 173, 0.2);
  stroke: var(--text-secondary);
}

.wardley-map__node--utility {
  fill: rgba(230, 232, 235, 0.16);
  stroke: var(--text-primary);
}

.wardley-map__caption {
  margin-top: var(--space-sm);
  font-size: var(--text-meta);
  color: var(--text-secondary);
}

/* Comparison table */
.comparison-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  overflow: hidden;
  margin: var(--space-lg) 0;
  font-size: 0.95rem;
}

.comparison-table thead th {
  text-align: left;
  font-family: var(--font-display);
  font-size: 0.95rem;
  background: rgba(76, 194, 255, 0.08);
  color: var(--text-primary);
}

.comparison-table th,
.comparison-table td {
  padding: 12px;
  border-bottom: 1px solid var(--border-subtle);
  vertical-align: top;
}

.comparison-table tbody tr:last-child td {
  border-bottom: none;
}

@media (max-width: 680px) {
  .wardley-map {
    padding: var(--space-sm);
  }

  .comparison-table {
    display: block;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
}

/* Article footer / back link */
.article-footer {
  margin-top: var(--space-xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-md);
}

/* === About Page === */
.about-page {
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

@media (max-width: 768px) {
  .about-page {
    padding: var(--space-lg) var(--space-md);
  }
}

.about-intro {
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: var(--line-height-body);
  margin-bottom: var(--space-lg);
}

/* === Utility Classes === */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* === Global Focus Styles === */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* === Reduced Motion === */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* === Scroll-in animations (progressive enhancement) === */
@media (prefers-reduced-motion: no-preference) {
  .post-card {
    opacity: 0;
    transform: translateY(14px);
    animation: fadeInUp 0.4s ease forwards;
  }

  .post-card:nth-child(1) { animation-delay: 0.05s; }
  .post-card:nth-child(2) { animation-delay: 0.15s; }
  .post-card:nth-child(3) { animation-delay: 0.25s; }
  .post-card:nth-child(4) { animation-delay: 0.35s; }
}

@keyframes fadeInUp {
  to {
    opacity: 1;
    transform: translateY(0);
  }
}