/* ============================================
   Life, The Universe & That Safety Thing
   Main Stylesheet
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
  /* Colors - Deep space dark theme */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a24;
  --bg-card: #16161f;
  
  --text-primary: #e8e8ed;
  --text-secondary: #a0a0b0;
  --text-muted: #6a6a7a;
  
  --accent-life: #4ecdc4;        /* Teal - organic, growth */
  --accent-universe: #a855f7;    /* Purple - cosmic, vast */
  --accent-safety: #f59e0b;      /* Amber - caution, importance */
  --accent-hover: #ffffff;
  
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-medium: rgba(255, 255, 255, 0.12);
  
  /* Typography */
  --font-display: 'Playfair Display', Georgia, serif;
  --font-body: 'Source Sans 3', -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
  --space-2xl: 8rem;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-medium: 300ms ease;
  --transition-slow: 500ms ease;
  
  /* Layout */
  --max-width: 1200px;
  --content-width: 720px;
}

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

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

body {
  font-family: var(--font-body);
  font-size: 1.1rem;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Subtle grain texture overlay */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  opacity: 0.03;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
  z-index: 9999;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.2;
  color: var(--text-primary);
}

h1 {
  font-size: clamp(2.5rem, 6vw, 4rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  margin-bottom: var(--space-md);
}

h3 {
  font-size: 1.5rem;
  margin-bottom: var(--space-sm);
}

p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
}

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

/* ---------- Layout ---------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

.content-narrow {
  max-width: var(--content-width);
  margin: 0 auto;
}

/* ---------- Header & Navigation ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: var(--space-md) 0;
  background: linear-gradient(to bottom, var(--bg-primary) 0%, transparent 100%);
  transition: background var(--transition-medium);
}

.site-header.scrolled {
  background: rgba(10, 10, 15, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Home button - separate location */
.home-link {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--border-medium);
  border-radius: 4px;
  transition: all var(--transition-fast);
  position: relative;
  overflow: hidden;
}

.home-link::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-life), var(--accent-universe), var(--accent-safety));
  opacity: 0.15;
  transition: left var(--transition-medium);
}

.home-link:hover::before {
  left: 0;
}

.home-link:hover {
  border-color: var(--text-muted);
}

/* Main navigation */
.main-nav {
  display: flex;
  gap: var(--space-xs);
}

.nav-link {
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-secondary);
  padding: var(--space-sm) var(--space-md);
  border-radius: 4px;
  position: relative;
  transition: all var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 50%;
  width: 0;
  height: 2px;
  transform: translateX(-50%);
  transition: width var(--transition-fast);
}

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

.nav-link:hover::after {
  width: calc(100% - var(--space-lg));
}

/* Section-specific colors */
.nav-link[data-section="life"]:hover::after,
.nav-link[data-section="life"].active::after {
  background: var(--accent-life);
  width: calc(100% - var(--space-lg));
}

.nav-link[data-section="universe"]:hover::after,
.nav-link[data-section="universe"].active::after {
  background: var(--accent-universe);
  width: calc(100% - var(--space-lg));
}

.nav-link[data-section="safety"]:hover::after,
.nav-link[data-section="safety"].active::after {
  background: var(--accent-safety);
  width: calc(100% - var(--space-lg));
}

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

/* Dropdown for sub-navigation */
.nav-item {
  position: relative;
}

.dropdown {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(10px);
  min-width: 160px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-medium);
  border-radius: 8px;
  padding: var(--space-sm);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.4);
}

.nav-item:hover .dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(4px);
}

.dropdown-link {
  display: block;
  padding: var(--space-sm) var(--space-md);
  font-size: 0.9rem;
  color: var(--text-secondary);
  border-radius: 4px;
  transition: all var(--transition-fast);
}

.dropdown-link:hover {
  color: var(--text-primary);
  background: var(--bg-tertiary);
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: all var(--transition-fast);
}

/* ---------- Hero Section ---------- */
.hero {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: var(--space-2xl) var(--space-lg);
  position: relative;
  overflow: hidden;
}

/* Animated gradient background */
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(ellipse at 30% 20%, rgba(78, 205, 196, 0.08) 0%, transparent 50%),
              radial-gradient(ellipse at 70% 60%, rgba(168, 85, 247, 0.08) 0%, transparent 50%),
              radial-gradient(ellipse at 50% 80%, rgba(245, 158, 11, 0.05) 0%, transparent 50%);
  animation: gradientDrift 20s ease-in-out infinite;
  pointer-events: none;
}

@keyframes gradientDrift {
  0%, 100% { transform: translate(0, 0) rotate(0deg); }
  33% { transform: translate(2%, -2%) rotate(1deg); }
  66% { transform: translate(-1%, 1%) rotate(-1deg); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-title {
  margin-bottom: var(--space-lg);
  opacity: 0;
  animation: fadeInUp 0.8s ease forwards;
}

.hero-title .line {
  display: block;
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--accent-life), var(--accent-universe), var(--accent-safety));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto var(--space-xl);
  opacity: 0;
  animation: fadeInUp 0.8s ease 0.2s forwards;
}

.hero-cta {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
  opacity: 0;
  animation: fadeInUp 0.8s ease 0.4s forwards;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 500;
  border-radius: 6px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn-primary {
  background: var(--text-primary);
  color: var(--bg-primary);
  border-color: var(--text-primary);
}

.btn-primary:hover {
  background: transparent;
  color: var(--text-primary);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border-color: var(--border-medium);
}

.btn-secondary:hover {
  border-color: var(--text-secondary);
  background: var(--bg-secondary);
}

/* ---------- Section Styles ---------- */
.section {
  padding: var(--space-2xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.section-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  padding: var(--space-xs) var(--space-md);
  border-radius: 4px;
  margin-bottom: var(--space-md);
}

.section-label.life {
  color: var(--accent-life);
  background: rgba(78, 205, 196, 0.1);
  border: 1px solid rgba(78, 205, 196, 0.2);
}

.section-label.universe {
  color: var(--accent-universe);
  background: rgba(168, 85, 247, 0.1);
  border: 1px solid rgba(168, 85, 247, 0.2);
}

.section-label.safety {
  color: var(--accent-safety);
  background: rgba(245, 158, 11, 0.1);
  border: 1px solid rgba(245, 158, 11, 0.2);
}

/* ---------- About Preview (Home Page) ---------- */
.about-preview {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
}

.about-content {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
  align-items: center;
}

.about-text h2 {
  margin-bottom: var(--space-md);
}

.about-placeholder {
  padding: var(--space-xl);
  border: 2px dashed var(--border-medium);
  border-radius: 8px;
  text-align: center;
  color: var(--text-muted);
  font-style: italic;
}

/* ---------- Card Grid ---------- */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--space-lg);
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  padding: var(--space-lg);
  transition: all var(--transition-medium);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--border-medium);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

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

.card.life::before { background: var(--accent-life); }
.card.universe::before { background: var(--accent-universe); }
.card.safety::before { background: var(--accent-safety); }

.card-meta {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-sm);
}

.card h3 {
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
  transition: color var(--transition-fast);
}

.card:hover h3 {
  color: var(--accent-hover);
}

.card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-bottom: 0;
}

.card-link {
  display: block;
  height: 100%;
}

/* ---------- Post List (for section pages) ---------- */
.post-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.post-item {
  display: flex;
  align-items: baseline;
  gap: var(--space-lg);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--border-subtle);
  transition: all var(--transition-fast);
}

.post-item:hover {
  padding-left: var(--space-md);
  background: var(--bg-secondary);
  margin: 0 calc(-1 * var(--space-md));
  padding-right: var(--space-md);
}

.post-number {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  min-width: 3ch;
}

.post-title {
  font-family: var(--font-display);
  font-size: 1.2rem;
  color: var(--text-primary);
  flex: 1;
}

.post-date {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Course sequence indicator */
.course-sequence {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.course-sequence h3 {
  font-size: 1rem;
  color: var(--accent-life);
  margin-bottom: var(--space-sm);
}

.course-sequence p {
  font-size: 0.95rem;
  margin-bottom: 0;
}

/* ---------- Page Header ---------- */
.page-header {
  padding: calc(var(--space-2xl) + 60px) 0 var(--space-xl);
  text-align: center;
  position: relative;
}

.page-header::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  border-radius: 2px;
}

.page-header.life::after { background: var(--accent-life); }
.page-header.universe::after { background: var(--accent-universe); }
.page-header.safety::after { background: var(--accent-safety); }

.page-header h1 {
  margin-bottom: var(--space-md);
}

.page-header .lead {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* ---------- Article Styles ---------- */
.article {
  padding: calc(var(--space-2xl) + 60px) 0 var(--space-2xl);
}

.article-header {
  text-align: center;
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-xl);
  border-bottom: 1px solid var(--border-subtle);
}

.article-meta {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
}

.article-content {
  font-size: 1.1rem;
}

.article-content h2 {
  margin-top: var(--space-xl);
}

.article-content h3 {
  margin-top: var(--space-lg);
}

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

.article-content a:hover {
  color: var(--accent-life);
}

.article-content blockquote {
  border-left: 3px solid var(--accent-universe);
  padding-left: var(--space-lg);
  margin: var(--space-lg) 0;
  font-style: italic;
  color: var(--text-secondary);
}

.article-content code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--bg-tertiary);
  padding: 0.2em 0.4em;
  border-radius: 4px;
}

.article-content pre {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: var(--space-lg);
  overflow-x: auto;
  margin: var(--space-lg) 0;
}

.article-content pre code {
  background: none;
  padding: 0;
}

/* Article navigation */
.article-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--space-lg);
  margin-top: var(--space-2xl);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--border-subtle);
}

.article-nav a {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
  padding: var(--space-md);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  max-width: 45%;
  transition: all var(--transition-fast);
}

.article-nav a:hover {
  border-color: var(--border-medium);
  background: var(--bg-secondary);
}

.article-nav .label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.article-nav .title {
  font-family: var(--font-display);
  color: var(--text-primary);
}

.article-nav .prev { text-align: left; }
.article-nav .next { text-align: right; margin-left: auto; }

/* ---------- Projects Grid ---------- */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
  gap: var(--space-lg);
}

.project-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 12px;
  overflow: hidden;
  transition: all var(--transition-medium);
}

.project-card:hover {
  transform: translateY(-4px);
  border-color: var(--accent-safety);
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
}

.project-card-body {
  padding: var(--space-lg);
}

.project-card h3 {
  margin-bottom: var(--space-sm);
}

.project-card p {
  font-size: 0.95rem;
  margin-bottom: var(--space-md);
}

.project-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  padding: var(--space-xs) var(--space-sm);
  background: var(--bg-tertiary);
  border-radius: 4px;
  color: var(--text-muted);
}

/* ---------- Footer ---------- */
.site-footer {
  padding: var(--space-xl) 0;
  border-top: 1px solid var(--border-subtle);
  text-align: center;
}

.footer-content {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--space-lg);
  margin-bottom: var(--space-md);
}

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

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

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  :root {
    --space-lg: 1.5rem;
    --space-xl: 3rem;
    --space-2xl: 5rem;
  }
  
  .header-inner {
    position: relative;
  }
  
  .main-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-secondary);
    border: 1px solid var(--border-subtle);
    border-radius: 8px;
    padding: var(--space-md);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-fast);
  }
  
  .main-nav.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(var(--space-sm));
  }
  
  .nav-toggle {
    display: flex;
  }
  
  .nav-item .dropdown {
    position: static;
    transform: none;
    opacity: 1;
    visibility: visible;
    box-shadow: none;
    border: none;
    background: transparent;
    padding-left: var(--space-md);
  }
  
  .about-content {
    grid-template-columns: 1fr;
  }
  
  .hero-cta {
    flex-direction: column;
    align-items: center;
  }
  
  .article-nav {
    flex-direction: column;
  }
  
  .article-nav a {
    max-width: 100%;
  }
  
  .post-item {
    flex-wrap: wrap;
  }
  
  .post-date {
    width: 100%;
    margin-left: calc(3ch + var(--space-lg));
  }
}

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

.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mt-xl { margin-top: var(--space-xl); }

.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }
.mb-lg { margin-bottom: var(--space-lg); }
.mb-xl { margin-bottom: var(--space-xl); }