/* ============================================
   CLOSED AI — Static Blog Stylesheet
   Dark theme with orange/cyan accents
   ============================================ */

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

:root {
  /* Colors */
  --bg-primary: #0a0a0b;
  --bg-secondary: #111113;
  --bg-card: #16161a;
  --bg-card-hover: #1c1c21;
  --bg-code: #1e1e24;

  --text-primary: #e8e6e3;
  --text-secondary: #9a9a9a;
  --text-muted: #666;

  --accent-primary: #ff6b35;
  --accent-primary-dim: rgba(255, 107, 53, 0.15);
  --accent-secondary: #00d9ff;
  --accent-secondary-dim: rgba(0, 217, 255, 0.1);

  --border-color: #222228;
  --border-subtle: #1a1a1f;

  /* Typography */
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-display: 'Playfair Display', Georgia, serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --max-width: 720px;
  --max-width-wide: 960px;
  --gutter: 24px;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  border-top: 3px solid var(--accent-primary);
}

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

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

::selection {
  background: var(--accent-primary-dim);
  color: var(--accent-primary);
}

/* --- Header --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 10, 11, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}

.header-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  padding: 16px var(--gutter);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-logo {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.5px;
  text-decoration: none;
}

.logo-closed {
  color: var(--text-primary);
}

.logo-ai {
  color: var(--accent-primary);
}

.site-logo:hover .logo-closed {
  color: var(--accent-secondary);
}

.site-nav {
  display: flex;
  gap: 24px;
}

.nav-link {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 1px;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--text-primary);
  border-bottom-color: var(--accent-primary);
}

/* --- Main Content --- */
#app {
  flex: 1;
  max-width: var(--max-width-wide);
  width: 100%;
  margin: 0 auto;
  padding: 0 var(--gutter);
}

/* --- Home / Archive View --- */
.home-view {
  padding: 48px 0 80px;
}

.home-hero {
  margin-bottom: 48px;
  padding-bottom: 40px;
  border-bottom: 1px solid var(--border-color);
  position: relative;
}

.home-hero::before {
  content: '';
  position: absolute;
  top: -60px;
  left: -100px;
  width: 400px;
  height: 300px;
  background: radial-gradient(ellipse, rgba(255, 107, 53, 0.06) 0%, transparent 70%);
  pointer-events: none;
  z-index: -1;
}

.home-hero h1 {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.home-hero h1 .hero-accent {
  color: var(--accent-primary);
}

.home-hero .hero-subtitle {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 560px;
  line-height: 1.6;
}

/* Category filter pills */
.category-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 36px;
}

.filter-pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--text-secondary);
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 20px;
  cursor: pointer;
  transition: all var(--transition-fast);
  user-select: none;
  letter-spacing: 0.3px;
}

.filter-pill:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

.filter-pill.active {
  background: var(--accent-primary-dim);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.filter-pill .pill-count {
  font-size: 0.7rem;
  opacity: 0.6;
}

/* Article list */
.article-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.article-card {
  display: block;
  padding: 24px 0;
  border-bottom: 1px solid var(--border-subtle);
  text-decoration: none;
  transition: all var(--transition-base);
}

.article-card:hover {
  padding-left: 12px;
  border-bottom-color: var(--border-color);
}

.article-card:hover .card-title {
  color: var(--accent-primary);
}

.card-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 8px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.card-date {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.5px;
}

.card-category {
  color: var(--accent-secondary);
  font-weight: 500;
}

.card-reading-time {
  opacity: 0.7;
}

.card-title {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1.3;
  color: var(--text-primary);
  margin-bottom: 8px;
  transition: color var(--transition-fast);
}

.card-excerpt {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --- Article View --- */
.article-view {
  padding: 48px 0 80px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.article-back {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 32px;
  transition: color var(--transition-fast);
}

.article-back:hover {
  color: var(--accent-primary);
}

.article-back::before {
  content: '←';
  font-size: 1rem;
}

.article-header {
  margin-bottom: 40px;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border-color);
}

.article-header .card-meta {
  margin-bottom: 16px;
}

.article-header .article-title {
  font-family: var(--font-display);
  font-size: 2.4rem;
  font-weight: 800;
  line-height: 1.15;
  color: var(--text-primary);
  margin-bottom: 16px;
}

.article-header .article-source {
  font-size: 0.82rem;
  color: var(--text-muted);
}

.article-header .article-source a {
  color: var(--text-secondary);
  border-bottom: 1px dashed var(--text-muted);
}

.article-header .article-source a:hover {
  color: var(--accent-secondary);
  border-bottom-color: var(--accent-secondary);
}

/* Article body typography */
.article-body {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-primary);
}

.article-body h1 {
  display: none; /* Title is rendered in the header */
}

.article-body h2 {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 700;
  margin: 48px 0 16px;
  color: var(--text-primary);
}

.article-body h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin: 36px 0 12px;
  color: var(--text-primary);
}

.article-body p {
  margin-bottom: 24px;
}

.article-body blockquote {
  border-left: 3px solid var(--accent-primary);
  margin: 28px 0;
  padding: 16px 24px;
  background: var(--bg-card);
  border-radius: 0 6px 6px 0;
  color: var(--text-secondary);
  font-style: italic;
}

.article-body blockquote p:last-child {
  margin-bottom: 0;
}

.article-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--bg-code);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent-secondary);
}

.article-body pre {
  background: var(--bg-code);
  padding: 20px;
  border-radius: 8px;
  overflow-x: auto;
  margin: 28px 0;
  border: 1px solid var(--border-color);
}

.article-body pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  color: var(--text-primary);
}

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

.article-body em {
  font-style: italic;
  color: var(--text-secondary);
}

.article-body ul, .article-body ol {
  margin: 16px 0 24px 20px;
}

.article-body li {
  margin-bottom: 8px;
}

.article-body hr {
  border: none;
  border-top: 1px solid var(--border-color);
  margin: 40px 0;
}

.article-body a {
  color: var(--accent-secondary);
  border-bottom: 1px solid transparent;
  transition: all var(--transition-fast);
}

.article-body a:hover {
  border-bottom-color: var(--accent-secondary);
}

/* Article footer */
.article-footer {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border-color);
}

.article-nav {
  display: flex;
  justify-content: space-between;
  gap: 24px;
}

.article-nav-link {
  flex: 1;
  padding: 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  text-decoration: none;
  transition: all var(--transition-base);
}

.article-nav-link:hover {
  border-color: var(--accent-primary);
  background: var(--bg-card-hover);
}

.article-nav-link.next {
  text-align: right;
}

.article-nav-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-bottom: 4px;
}

.article-nav-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.4;
}

/* --- About View --- */
.about-view {
  padding: 48px 0 80px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.about-view h1 {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 800;
  margin-bottom: 32px;
  color: var(--text-primary);
}

.about-view p {
  font-size: 1.05rem;
  line-height: 1.8;
  color: var(--text-secondary);
  margin-bottom: 20px;
}

.about-view p strong {
  color: var(--text-primary);
}

.about-view .about-signoff {
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
  font-family: var(--font-mono);
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* --- Footer --- */
.site-footer {
  border-top: 1px solid var(--border-color);
  background: var(--bg-secondary);
  padding: 40px var(--gutter);
  margin-top: auto;
}

.footer-inner {
  max-width: var(--max-width-wide);
  margin: 0 auto;
  text-align: center;
}

.footer-tagline {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-primary);
  margin-bottom: 12px;
  letter-spacing: 1px;
}

.footer-links {
  margin-bottom: 12px;
  font-size: 0.78rem;
}

.footer-links a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

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

.footer-sep {
  color: var(--text-muted);
  margin: 0 8px;
}

.footer-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer-domain {
  font-family: var(--font-mono);
  color: var(--text-secondary);
}

/* --- Loading State --- */
.loading {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 120px 0;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.loading::before {
  content: '';
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin-right: 12px;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* --- Empty State --- */
.empty-state {
  padding: 80px 0;
  text-align: center;
  color: var(--text-muted);
}

.empty-state .empty-icon {
  font-size: 2rem;
  margin-bottom: 12px;
  opacity: 0.4;
}

.empty-state p {
  font-size: 0.95rem;
}

/* --- 404 --- */
.not-found {
  padding: 120px 0;
  text-align: center;
}

.not-found h1 {
  font-family: var(--font-mono);
  font-size: 4rem;
  color: var(--accent-primary);
  margin-bottom: 12px;
}

.not-found p {
  color: var(--text-muted);
  margin-bottom: 24px;
}

/* --- Fade-in animation --- */
.fade-in {
  animation: fadeIn 0.3s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* --- Responsive --- */
@media (max-width: 768px) {
  :root {
    --gutter: 16px;
  }

  .home-hero h1 {
    font-size: 1.8rem;
  }

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

  .article-header .article-title {
    font-size: 1.8rem;
  }

  .article-body {
    font-size: 1rem;
  }

  .article-nav {
    flex-direction: column;
  }

  .article-nav-link.next {
    text-align: left;
  }

  .category-filters {
    gap: 6px;
  }

  .filter-pill {
    font-size: 0.72rem;
    padding: 5px 10px;
  }
}

@media (max-width: 480px) {
  .home-hero h1 {
    font-size: 1.5rem;
  }

  .card-title {
    font-size: 1.1rem;
  }

  .article-header .article-title {
    font-size: 1.5rem;
  }

  .card-meta {
    flex-wrap: wrap;
    gap: 6px;
  }
}

/* --- Scrollbar --- */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}