/* AI Persona Lab — warm, elegant, intellectual design */

:root {
  --bg: #FDFBF7;
  --bg-card: #FFFFFF;
  --text: #2D2A26;
  --text-secondary: #6B6560;
  --text-muted: #9E9792;
  --accent: #5A7D9A;
  --accent-light: #E8F0F6;
  --accent-warm: #C4956A;
  --border: #EDE8E2;
  --shadow: rgba(45, 42, 38, 0.06);
  --shadow-hover: rgba(45, 42, 38, 0.12);
  --radius: 12px;
  --font: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-serif: Georgia, 'Times New Roman', serif;
  --max-width: 860px;
  --nav-height: 64px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Canvas for floating particles */
#antigravity-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  opacity: 0.45;
}

/* Navigation */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(253, 251, 247, 0.88);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
}

.nav-inner {
  width: 100%;
  max-width: 1100px;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  letter-spacing: -0.01em;
  transition: opacity 0.2s;
}

.nav-logo:hover {
  opacity: 0.7;
}

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

.nav-links {
  display: flex;
  gap: 8px;
  list-style: none;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.875rem;
  padding: 6px 14px;
  border-radius: 8px;
  transition: all 0.2s;
}

.nav-links a:hover {
  color: var(--text);
  background: rgba(0, 0, 0, 0.04);
}

.nav-links a.active {
  color: var(--accent);
  background: var(--accent-light);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  color: var(--text);
}

.nav-toggle svg {
  width: 24px;
  height: 24px;
}

/* Main content */
.main {
  position: relative;
  z-index: 1;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: calc(var(--nav-height) + 48px) 24px 80px;
}

/* Hero section */
.hero {
  text-align: center;
  padding: 64px 0 48px;
}

.hero-badge {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--text-muted);
  background: rgba(0, 0, 0, 0.03);
  padding: 6px 16px;
  border-radius: 20px;
  margin-bottom: 24px;
  letter-spacing: 0.02em;
}

.hero-badge a {
  color: var(--accent);
  text-decoration: none;
}

.hero-badge a:hover {
  text-decoration: underline;
}

.hero h1 {
  font-family: var(--font-serif);
  font-size: 2.8rem;
  font-weight: 600;
  letter-spacing: -0.03em;
  line-height: 1.2;
  margin-bottom: 20px;
  color: var(--text);
}

.hero p {
  font-size: 1.12rem;
  color: var(--text-secondary);
  max-width: 580px;
  margin: 0 auto 32px;
  line-height: 1.7;
}

.hero-links {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 10px;
  font-size: 0.95rem;
  text-decoration: none;
  transition: all 0.25s ease;
  font-weight: 500;
  border: none;
  cursor: pointer;
}

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

.btn-primary:hover {
  background: #4D6E88;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(90, 125, 154, 0.25);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--accent);
  transform: translateY(-1px);
  box-shadow: 0 4px 16px var(--shadow);
}

/* Cards grid */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  margin: 32px 0;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  text-decoration: none;
  color: var(--text);
  transition: all 0.3s ease;
  display: block;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px var(--shadow-hover);
  border-color: transparent;
}

.card-icon {
  font-size: 1.5rem;
  margin-bottom: 12px;
  display: block;
}

.card h3 {
  font-size: 1.05rem;
  margin-bottom: 8px;
  font-weight: 600;
}

.card p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* Content typography */
.content {
  animation: fadeIn 0.4s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

.content h1 {
  font-family: var(--font-serif);
  font-size: 2.2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
  line-height: 1.25;
}

.content h2 {
  font-family: var(--font-serif);
  font-size: 1.55rem;
  font-weight: 600;
  margin-top: 48px;
  margin-bottom: 16px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  letter-spacing: -0.01em;
}

.content h2:first-of-type {
  border-top: none;
  padding-top: 0;
}

.content h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 12px;
}

.content h4 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-top: 24px;
  margin-bottom: 10px;
}

.content p {
  margin-bottom: 16px;
  color: var(--text);
}

.content a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.2s;
}

.content a:hover {
  border-bottom-color: var(--accent);
}

.content ul, .content ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.content li {
  margin-bottom: 6px;
}

.content li::marker {
  color: var(--text-muted);
}

.content strong {
  font-weight: 600;
  color: var(--text);
}

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

.content blockquote {
  border-left: 3px solid var(--accent);
  background: var(--accent-light);
  padding: 16px 20px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
  font-size: 0.95rem;
  color: var(--text-secondary);
}

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

.content pre {
  background: #2D2A26;
  color: #E8E2DA;
  padding: 20px 24px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 20px 0;
  font-size: 0.88rem;
  line-height: 1.6;
}

.content code {
  background: rgba(0, 0, 0, 0.05);
  padding: 2px 7px;
  border-radius: 5px;
  font-size: 0.9em;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
}

.content pre code {
  background: none;
  padding: 0;
  border-radius: 0;
  color: inherit;
}

.content img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
  margin: 16px 0;
  border: 1px solid var(--border);
}

/* Tables */
.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: 0.92rem;
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

.content thead th {
  background: rgba(0, 0, 0, 0.03);
  font-weight: 600;
  text-align: left;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.content tbody td {
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  vertical-align: top;
}

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

.content tbody tr:hover {
  background: rgba(0, 0, 0, 0.015);
}

/* Details/summary (collapsible) */
.content details {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin: 16px 0;
}

.content details summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--accent);
  user-select: none;
}

.content details[open] summary {
  margin-bottom: 12px;
}

/* Caution/note boxes */
.callout {
  border-left: 3px solid var(--accent-warm);
  background: rgba(196, 149, 106, 0.08);
  padding: 16px 20px;
  margin: 20px 0;
  border-radius: 0 8px 8px 0;
}

.callout-title {
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--accent-warm);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

/* Section separator */
.separator {
  height: 1px;
  background: var(--border);
  margin: 48px 0;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 32px;
  flex-wrap: wrap;
}

.breadcrumb a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

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

.breadcrumb .sep {
  font-size: 0.7rem;
}

/* Footer */
.footer {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 32px 24px;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer a {
  color: var(--accent);
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}

/* Checkbox styling in lists */
.content li input[type="checkbox"] {
  margin-right: 6px;
  accent-color: var(--accent);
}

/* Section links grid (for instructions index) */
.link-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
  margin: 24px 0;
}

.link-grid a {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 16px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text);
  font-size: 0.92rem;
  transition: all 0.25s;
}

.link-grid a:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 4px 16px var(--shadow);
}

.link-grid .icon {
  font-size: 1.3rem;
  flex-shrink: 0;
}

/* Mermaid placeholder */
.mermaid-placeholder {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  margin: 20px 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }

  .content h1 {
    font-size: 1.7rem;
  }

  .content h2 {
    font-size: 1.3rem;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: rgba(253, 251, 247, 0.96);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 16px;
    border-bottom: 1px solid var(--border);
    gap: 4px;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-toggle {
    display: block;
  }

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

  .main {
    padding-left: 16px;
    padding-right: 16px;
  }

  .content table {
    display: block;
    overflow-x: auto;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.6rem;
  }

  .hero-links {
    flex-direction: column;
    align-items: center;
  }

  .btn {
    width: 100%;
    justify-content: center;
  }
}