/* Knowledge Discovery - Dark Academic Theme with Geometric Font */

@import url('https://fonts.googleapis.com/css2?family=Jost:wght@400;500;600;700&display=swap');

:root {
  --color-bg: #1a1a2e;
  --color-surface: #16213e;
  --color-surface-elevated: #1f2b4d;
  --color-text: #e8e8e8;
  --color-text-muted: #a0a0b0;
  --color-primary: #d4af37;
  --color-primary-dark: #b8960c;
  --color-accent: #c9a227;
  --color-border: #2a2a4a;
  --color-code-bg: #0f0f1a;
  --font-sans: "Jost", -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: "SF Mono", "Fira Code", monospace;
  --max-width: 960px;
  --spacing: 1.5rem;
}

* {
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  margin: 0;
  padding: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 400 400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noiseFilter'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noiseFilter)'/%3E%3C/svg%3E");
  background-blend-mode: overlay;
  background-size: 200px;
}

/* Layout */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing);
}

/* Header */
header {
  background: linear-gradient(180deg, var(--color-surface) 0%, transparent 100%);
  padding: 1.5rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.site-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.site-title:hover {
  color: var(--color-text);
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 2rem;
}

nav a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  transition: color 0.3s;
}

nav a:hover,
nav a.active {
  color: var(--color-primary);
}

/* Main content */
main {
  padding: var(--spacing) 0 4rem;
}

/* Typography */
h1, h2, h3, h4 {
  font-family: var(--font-sans);
  margin: 2.5rem 0 1rem;
  line-height: 1.2;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

h1 { font-size: 2.5rem; margin-top: 0; letter-spacing: 0.05em; }
h2 {
  font-size: 1.5rem;
  color: var(--color-primary);
  border-bottom: none;
  position: relative;
  padding-bottom: 0.75rem;
  letter-spacing: 0.1em;
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 60px;
  height: 3px;
  background: var(--color-primary);
}

h3 { font-size: 1.15rem; letter-spacing: 0.08em; }
h4 { font-size: 1rem; }

p {
  margin: 1rem 0;
  text-transform: none;
  letter-spacing: normal;
}

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

a:hover {
  color: var(--color-text);
}

/* Lists */
ul, ol {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

li {
  margin: 0.6rem 0;
}

/* Code */
code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-code-bg);
  padding: 0.2rem 0.5rem;
  border-radius: 4px;
  border: 1px solid var(--color-border);
}

pre {
  background: var(--color-code-bg);
  padding: 1.25rem;
  border-radius: 8px;
  overflow-x: auto;
  border: 1px solid var(--color-border);
}

pre code {
  background: none;
  padding: 0;
  border: none;
}

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
}

th, td {
  padding: 0.875rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

th {
  font-weight: 600;
  background: var(--color-surface);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.85rem;
}

tr:hover td {
  background: var(--color-surface);
}

/* Cards */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 1rem 0;
}

.card h3 {
  margin-top: 0;
}

/* Prose pages (rendered from markdown docs, e.g. /projects/*) */
.prose {
  font-size: 0.98rem;
}

.prose h2 {
  margin-top: 2.5rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--color-border);
}

.prose h3 {
  margin-top: 2rem;
  color: var(--color-accent);
}

.prose hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2.5rem 0;
}

.prose table {
  font-size: 0.92rem;
}

.prose blockquote {
  border-left: 3px solid var(--color-accent);
  margin: 1.5rem 0;
  padding: 0.25rem 1rem;
  color: var(--color-text-muted);
  background: var(--color-surface);
}

/* Module cards on homepage */
.part-title {
  margin: 2.5rem 0 0.5rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--color-border);
  color: var(--color-accent);
  font-size: 1.15rem;
  letter-spacing: 0.02em;
}

.modules-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin: 1rem 0 0.5rem;
}

.module-card {
  background: linear-gradient(145deg, var(--color-surface) 0%, var(--color-surface-elevated) 100%);
  border: 1px solid var(--color-border);
  border-radius: 12px;
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

.module-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary) 0%, transparent 100%);
  opacity: 0;
  transition: opacity 0.3s;
}

.module-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.4);
  text-decoration: none;
}

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

.module-card .number {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.15em;
  margin-bottom: 0.5rem;
}

.module-card .title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  line-height: 1.4;
  text-transform: none;
  letter-spacing: 0.01em;
}

.module-card .description {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  margin: 0;
  line-height: 1.5;
}

/* Announcement */
.announcement {
  background: linear-gradient(135deg, rgba(212, 175, 55, 0.15) 0%, rgba(212, 175, 55, 0.05) 100%);
  border: 1px solid var(--color-primary);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  margin: 2rem 0;
}

.announcement strong {
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.9rem;
}

/* Hero section */
.hero {
  padding: 3rem 0;
  margin-bottom: 1rem;
  text-align: center;
}

.hero h1 {
  font-size: 2.75rem;
  margin-bottom: 0.75rem;
  background: linear-gradient(135deg, var(--color-text) 0%, var(--color-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: 0.08em;
}

.hero .subtitle {
  font-size: 1rem;
  color: var(--color-text-muted);
  margin: 0;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  font-weight: 500;
}

/* Footer */
footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  margin-top: 4rem;
  color: var(--color-text-muted);
  font-size: 0.85rem;
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* Session page styles */
.session-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--color-border);
}

.session-header .number {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: 0.15em;
}

.session-header h1 {
  margin: 0.25rem 0 0.5rem;
}

.session-header .meta {
  color: var(--color-text-muted);
  font-size: 0.95rem;
}

/* Callout boxes */
.objectives {
  background: rgba(212, 175, 55, 0.1);
  border-left: 4px solid var(--color-primary);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  border-radius: 0 8px 8px 0;
}

.objectives h3 {
  margin-top: 0;
  color: var(--color-primary);
}

.example {
  background: rgba(34, 197, 94, 0.1);
  border-left: 4px solid #22c55e;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  border-radius: 0 6px 6px 0;
}

.formula {
  background: var(--color-code-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  margin: 1rem 0;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  text-align: center;
}

.formula-name {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}

/* Insight box */
.insight {
  background: rgba(96, 165, 250, 0.1);
  border-left: 4px solid #60a5fa;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  border-radius: 0 6px 6px 0;
}

.insight-title {
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #60a5fa;
  margin-bottom: 0.5rem;
}

/* Definition box */
.definition {
  background: rgba(168, 85, 247, 0.1);
  border-left: 4px solid #a855f7;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  border-radius: 0 6px 6px 0;
}

.definition-title {
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #a855f7;
  margin-bottom: 0.5rem;
}

/* Trap / warning box */
.trap {
  background: rgba(239, 68, 68, 0.1);
  border-left: 4px solid #ef4444;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
  border-radius: 0 6px 6px 0;
}

.trap-title {
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #ef4444;
  margin-bottom: 0.5rem;
}

/* Example title */
.example-title {
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #22c55e;
  margin-bottom: 0.5rem;
}

/* Source attribution */
.source-attribution {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin: 1rem 0;
}

.source-attribution h4 {
  margin-top: 0;
  color: var(--color-primary);
}

/* Details / collapsible */
details {
  margin: 1rem 0;
}

details summary {
  cursor: pointer;
  padding: 0.75rem 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 6px;
  transition: background 0.2s;
}

details summary:hover {
  background: var(--color-surface-elevated);
}

details[open] summary {
  border-radius: 6px 6px 0 0;
  border-bottom: 1px solid var(--color-border);
}

details[open] > .card {
  border-top: none;
  border-radius: 0 0 8px 8px;
}

/* Topic navigation */
.topic-nav {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin: 1.5rem 0;
  padding: 1rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
}

.topic-nav a {
  padding: 0.5rem 1rem;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  border: 1px solid var(--color-border);
  transition: all 0.2s;
}

.topic-nav a:hover {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: rgba(212, 175, 55, 0.1);
}

/* Topic divider */
.topic-divider {
  margin: 3rem 0 1rem;
  padding: 1.25rem 0;
  border-top: 3px solid var(--color-primary);
  display: flex;
  align-items: baseline;
  gap: 1rem;
  scroll-margin-top: 5rem;
}

.topic-divider-number {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--color-primary);
  letter-spacing: 0.15em;
}

.topic-divider-title {
  font-size: 1.3rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text);
}

/* Responsive */
@media (max-width: 640px) {
  :root {
    --spacing: 1rem;
  }

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

  nav ul {
    gap: 1rem;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

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

  table {
    font-size: 0.9rem;
  }

  th, td {
    padding: 0.5rem;
  }
}