/* ============================================================
   BOTBUHDY QUANTUM — A BotBuhdy Exploration
   World-class dark aesthetic — v1.0
   Space Grotesk · Inter · JetBrains Mono
   ============================================================ */

:root {
  /* Core palette */
  --bg-deep:       #04040f;
  --bg-mid:        #070712;
  --bg-card:       #0b0b1e;
  --bg-card-hover: #0f0f26;

  /* Electric blues / cyans */
  --electric-blue: #00B4D8;
  --ocean-blue:    #0077B6;
  --cyan:          #00F5D4;
  --teal:          #00E5CC;

  /* Purples */
  --neural-purple: #7B2FBE;
  --violet:        #9D4EDD;
  --deep-violet:   #6A0DAD;

  /* Quantum accent — gold for uncertainty */
  --quantum-gold:  #FFD700;
  --amber:         #FFAB40;

  /* Text */
  --text-primary:  #E8E8F8;
  --text-muted:    #8080AA;
  --text-dim:      #484868;

  /* Fonts */
  --font-display: 'Space Grotesk', -apple-system, sans-serif;
  --font-body:    'Inter', -apple-system, sans-serif;
  --font-mono:    'JetBrains Mono', 'Courier New', monospace;
  --font-serif:   Georgia, 'Times New Roman', serif;

  /* Glows */
  --glow-blue:   0 0 30px rgba(0, 180, 216, 0.35);
  --glow-cyan:   0 0 30px rgba(0, 245, 212, 0.35);
  --glow-purple: 0 0 30px rgba(157, 78, 221, 0.35);
  --glow-gold:   0 0 30px rgba(255, 215, 0, 0.3);

  /* Borders */
  --border-subtle: rgba(0, 180, 216, 0.12);
  --border-glow:   rgba(0, 180, 216, 0.5);

  /* Transitions */
  --transition-base: 0.4s ease-out;
  --transition-fast: 0.2s ease-out;
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  background: var(--bg-deep);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.85;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  animation: body-fade-in 0.6s ease-out both;
}

@keyframes body-fade-in {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* ── Grain Overlay ── */
.grain-overlay {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 1;
  opacity: 0.025;
  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");
  background-repeat: repeat;
  background-size: 200px 200px;
}

/* ── Grid Background ── */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(0, 180, 216, 0.018) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 180, 216, 0.018) 1px, transparent 1px);
  background-size: 60px 60px;
  pointer-events: none;
  z-index: 0;
}

/* ── Layout ── */
.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1.5rem;
  position: relative;
  z-index: 1;
}

/* ============================================================
   HEADER
   ============================================================ */
.quantum-topbar {
  background: rgba(4, 4, 15, 0.98);
  border-bottom: 1px solid rgba(0, 180, 216, 0.05);
}
.topbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0.3rem 1.5rem;
}
.topbar-back {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-dim);
  text-decoration: none;
  letter-spacing: 0.04em;
  transition: color 0.2s;
}
.topbar-back:hover { color: var(--electric-blue); }
.topbar-tag {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  opacity: 0.5;
}

/* ── Site Header ── */
.site-header {
  background: rgba(4, 4, 15, 0.95);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(0, 180, 216, 0.1);
  position: sticky;
  top: 0;
  z-index: 500;
  padding: 0;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0.6rem 1.5rem;
}
.site-logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  text-decoration: none;
}
.logo-pulse {
  font-size: 1.5rem;
  animation: pulse-glow 4s ease-in-out infinite;
}
.logo-text {
  display: flex;
  flex-direction: column;
}
.logo-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--cyan);
  letter-spacing: 0.02em;
  line-height: 1.2;
}
.logo-sub {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* Mobile back button */
.mobile-back-btn {
  display: none;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-muted);
  text-decoration: none;
  padding: 0.3rem 0.6rem;
  border: 1px solid var(--border-subtle);
  border-radius: 5px;
  transition: all 0.2s;
}
.mobile-back-btn:hover { color: var(--cyan); border-color: var(--cyan); }

/* Hamburger */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  padding: 8px 10px;
  cursor: pointer;
  transition: border-color 0.2s;
}
.hamburger:hover { border-color: var(--electric-blue); }
.hamburger span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--cyan);
  border-radius: 2px;
  transition: all 0.3s;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Navigation Bar ── */
.quantum-nav {
  background: rgba(5, 5, 16, 0.95);
  border-bottom: 1px solid rgba(0, 180, 216, 0.07);
  position: sticky;
  top: 50px;
  z-index: 499;
  overflow-x: auto;
  scrollbar-width: none;
}
.quantum-nav::-webkit-scrollbar { display: none; }
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0;
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 1rem;
  white-space: nowrap;
}
.nav-link {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.65rem 1rem;
  font-family: var(--font-display);
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: all 0.2s;
  white-space: nowrap;
}
.nav-link:hover {
  color: var(--cyan);
  background: rgba(0, 245, 212, 0.03);
}
.nav-link.active {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}
.nav-icon { font-size: 0.85rem; }

/* ── Mobile Nav Overlay ── */
.mobile-nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(4, 4, 15, 0.99);
  z-index: 600;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s, visibility 0.3s;
  overflow-y: scroll;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
}
.mobile-nav-overlay.open { opacity: 1; visibility: visible; }
.mobile-nav-inner {
  max-width: 400px;
  margin: 0 auto;
  padding: 1.5rem 1.5rem 3rem;
}
.mobile-nav-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}
.mobile-nav-title {
  font-family: var(--font-display);
  font-size: 1rem;
  color: var(--cyan);
}
.mobile-nav-close {
  background: none;
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  padding: 0.3rem 0.7rem;
  color: var(--text-muted);
  font-size: 1.1rem;
  cursor: pointer;
  transition: all 0.2s;
}
.mobile-nav-close:hover { color: var(--cyan); border-color: var(--electric-blue); }
.mobile-nav-links {
  display: flex;
  flex-direction: column;
  gap: 0;
}
.mobile-nav-links a {
  display: block;
  padding: 0.85rem 0.6rem;
  font-family: var(--font-sans, var(--font-body));
  font-size: 1rem;
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 180, 216, 0.06);
  transition: all 0.15s;
}
.mobile-nav-links a:hover {
  color: var(--cyan);
  padding-left: 1.2rem;
  background: rgba(0, 245, 212, 0.03);
}
.mobile-nav-links a.active {
  color: var(--cyan);
  font-weight: 600;
  border-left: 3px solid var(--cyan);
  padding-left: 0.8rem;
}
.mobile-nav-foot {
  margin-top: 2rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border-subtle);
}
.mobile-back {
  display: block;
  text-align: center;
  padding: 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dim);
  text-decoration: none;
  border: 1px solid var(--border-subtle);
  border-radius: 6px;
  transition: all 0.2s;
}
.mobile-back:hover { color: var(--electric-blue); border-color: var(--electric-blue); }

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  margin-top: 7rem;
  position: relative;
  background: linear-gradient(180deg, transparent 0%, rgba(0,180,216,0.018) 100%);
}
.footer-wave {
  position: relative;
  height: 60px;
  overflow: hidden;
}
.footer-wave svg {
  position: absolute;
  bottom: 0;
  width: 100%;
  height: 100%;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1.3fr 2fr;
  gap: 3rem;
  max-width: 1120px;
  margin: 0 auto;
  padding: 3rem 1.5rem 2.5rem;
}
.footer-brand-col {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.footer-logo-mark {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}
.footer-pulse {
  font-size: 1.8rem;
  animation: pulse-glow 4s ease-in-out infinite;
}
.footer-brand-text {
  display: flex;
  flex-direction: column;
}
.footer-brand-name {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--cyan);
}
.footer-brand-sub {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}
.footer-description {
  font-family: var(--font-body);
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.7;
}
.footer-disclaimer-text {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-dim);
  letter-spacing: 0.04em;
  padding: 0.6rem 0.8rem;
  background: rgba(0,180,216,0.03);
  border: 1px solid rgba(0,180,216,0.06);
  border-radius: 6px;
}
.footer-nav-cols {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.footer-col {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}
.footer-col-title {
  font-family: var(--font-display);
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--electric-blue);
  text-transform: uppercase;
  letter-spacing: 0.14em;
  padding-bottom: 0.5rem;
  margin-bottom: 0.2rem;
  border-bottom: 1px solid rgba(0,180,216,0.1);
}
.footer-col a {
  font-family: var(--font-body);
  font-size: 0.82rem;
  color: var(--text-dim);
  text-decoration: none;
  padding: 0.2rem 0;
  transition: all 0.2s;
}
.footer-col a:hover {
  color: var(--cyan);
  padding-left: 0.4rem;
}
.footer-bottom-bar {
  border-top: 1px solid rgba(0,180,216,0.08);
  background: rgba(0,0,0,0.2);
}
.footer-bottom-inner {
  max-width: 1120px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-dim);
  letter-spacing: 0.06em;
}
.footer-bottom-inner strong { color: var(--text-muted); }
.footer-sep { color: var(--quantum-gold); opacity: 0.4; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  padding: 6rem 0 4rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero-bg-img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  opacity: 0.14;
  z-index: 0;
  filter: blur(2px) saturate(1.5);
}

/* gradient placeholder when no image */
.hero-bg-placeholder {
  position: absolute;
  inset: 0;
  z-index: 0;
  background: radial-gradient(ellipse 80% 60% at 50% 40%,
    rgba(0, 180, 216, 0.12) 0%,
    rgba(157, 78, 221, 0.08) 50%,
    transparent 100%);
}

.hero > *:not(.hero-bg-img):not(.hero-bg-placeholder) {
  position: relative;
  z-index: 1;
}
.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 140px;
  background: linear-gradient(transparent, var(--bg-deep));
  pointer-events: none;
  z-index: 2;
}
.hero-icon {
  font-size: 3.5rem;
  display: block;
  margin-bottom: 1.5rem;
  animation: float 6s ease-in-out infinite;
}
.hero-title {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 5.5vw, 4.2rem);
  font-weight: 700;
  line-height: 1.05;
  margin-bottom: 1.5rem;
  background: linear-gradient(270deg, var(--cyan), var(--electric-blue), var(--violet), var(--cyan));
  background-size: 300% 300%;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  animation: shimmer-gradient 8s ease-in-out infinite;
}
@keyframes shimmer-gradient {
  0%   { background-position: 0% 50%; }
  50%  { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}
.hero-subtitle {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 680px;
  margin: 0 auto 2.5rem;
  line-height: 1.9;
  font-style: italic;
}
.hero-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--quantum-gold);
  border: 1px solid rgba(255, 215, 0, 0.35);
  padding: 0.45rem 1.2rem;
  border-radius: 4px;
  background: rgba(255, 215, 0, 0.05);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  animation: pulse-gold 4s ease-in-out infinite;
}

/* ── Page Header (inner pages) ── */
.page-header {
  padding: 4rem 0 2.5rem;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 3.5rem;
  position: relative;
  overflow: hidden;
}
.page-header-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  background: radial-gradient(ellipse 70% 80% at 10% 50%,
    rgba(0, 180, 216, 0.06) 0%,
    transparent 70%);
  pointer-events: none;
}
.page-header > *:not(.page-header-bg) { position: relative; z-index: 1; }
.page-icon {
  font-size: 2.8rem;
  margin-bottom: 1rem;
  display: block;
}
.page-header h1 {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4.5vw, 3rem);
  font-weight: 700;
  background: linear-gradient(135deg, var(--cyan), var(--electric-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 0.75rem;
  line-height: 1.1;
}
.page-header .subtitle {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  color: var(--text-muted);
  font-style: italic;
  max-width: 640px;
  line-height: 1.8;
}
.page-header .page-meta {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-top: 1.25rem;
  flex-wrap: wrap;
}
.page-tag {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.25rem 0.8rem;
  border-radius: 4px;
  background: rgba(0, 180, 216, 0.08);
  border: 1px solid rgba(0, 180, 216, 0.2);
  color: var(--electric-blue);
}
.page-tag.tag-purple {
  background: rgba(157, 78, 221, 0.08);
  border-color: rgba(157, 78, 221, 0.2);
  color: var(--violet);
}
.page-tag.tag-gold {
  background: rgba(255, 215, 0, 0.07);
  border-color: rgba(255, 215, 0, 0.25);
  color: var(--quantum-gold);
}

/* ============================================================
   IMAGE PLACEHOLDER (for hero images)
   ============================================================ */
.hero-img-placeholder {
  width: 100%;
  max-width: 900px;
  margin: 0 auto 3rem;
  border-radius: 12px;
  border: 1px solid var(--border-subtle);
  overflow: hidden;
  position: relative;
  z-index: 1;
  aspect-ratio: 16/7;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 12px 60px rgba(0, 0, 0, 0.7), var(--glow-blue);
}

/* Unique gradient per page class */
body.page-home       .hero-img-placeholder { background: radial-gradient(ellipse at 40% 50%, rgba(0,180,216,0.3) 0%, rgba(157,78,221,0.2) 50%, rgba(4,4,15,0.9) 100%); }
body.page-dslit      .hero-img-placeholder { background: radial-gradient(ellipse at 50% 40%, rgba(0,245,212,0.25) 0%, rgba(0,119,182,0.2) 60%, rgba(4,4,15,0.9) 100%); }
body.page-eraser     .hero-img-placeholder { background: radial-gradient(ellipse at 30% 60%, rgba(157,78,221,0.3) 0%, rgba(0,180,216,0.15) 60%, rgba(4,4,15,0.9) 100%); }
body.page-dimensions .hero-img-placeholder { background: radial-gradient(ellipse at 60% 40%, rgba(255,215,0,0.2) 0%, rgba(157,78,221,0.25) 50%, rgba(4,4,15,0.9) 100%); }
body.page-biology    .hero-img-placeholder { background: radial-gradient(ellipse at 45% 55%, rgba(0,245,212,0.2) 0%, rgba(0,180,216,0.15) 50%, rgba(4,4,15,0.9) 100%); }
body.page-computing  .hero-img-placeholder { background: radial-gradient(ellipse at 50% 50%, rgba(0,180,216,0.25) 0%, rgba(7,7,18,0.9) 100%); }
body.page-simulation .hero-img-placeholder { background: radial-gradient(ellipse at 50% 50%, rgba(157,78,221,0.25) 0%, rgba(106,13,173,0.15) 50%, rgba(4,4,15,0.9) 100%); }
body.page-synthesis  .hero-img-placeholder { background: conic-gradient(from 180deg at 50% 50%, rgba(0,245,212,0.15), rgba(157,78,221,0.2), rgba(255,215,0,0.12), rgba(0,180,216,0.15), rgba(0,245,212,0.15)); }

.hero-img-placeholder .placeholder-content {
  text-align: center;
  z-index: 2;
}
.hero-img-placeholder .placeholder-icon {
  font-size: 3rem;
  display: block;
  margin-bottom: 0.5rem;
  opacity: 0.6;
}
.hero-img-placeholder .placeholder-text {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-dim);
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* Particle animation overlay on placeholder */
.hero-img-placeholder::after {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent 0px,
    transparent 2px,
    rgba(0, 180, 216, 0.015) 2px,
    rgba(0, 180, 216, 0.015) 3px
  );
  pointer-events: none;
}

/* ============================================================
   SECTIONS & CARDS
   ============================================================ */
.section { margin-bottom: 4.5rem; }

.section-title {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--electric-blue);
  text-transform: uppercase;
  letter-spacing: 0.18em;
  margin-bottom: 1.75rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.section-title::before {
  content: '';
  display: block;
  width: 28px;
  height: 1px;
  background: var(--electric-blue);
  opacity: 0.6;
}
.section-title::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, var(--border-subtle), transparent);
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: 1.5rem;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0, 245, 212, 0.6), transparent);
  opacity: 0;
  transition: opacity var(--transition-base);
}
.card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(0, 180, 216, 0.28);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4), 0 8px 40px rgba(0, 180, 216, 0.1);
  transform: translateY(-3px);
}
.card:hover::before { opacity: 1; }

.card-title {
  font-family: var(--font-display);
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--cyan);
  margin-bottom: 0.6rem;
  letter-spacing: 0.02em;
}
.card-body {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.75;
}
.card-icon {
  font-size: 1.8rem;
  margin-bottom: 0.75rem;
  display: block;
}

/* Card Grids */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}
.card-grid-2 {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 1.5rem;
}
.card-grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

/* ── Stat Cards ── */
.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: 1.5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
  transition: all var(--transition-base);
}
.stat-card::before {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--electric-blue), var(--cyan));
  opacity: 0.5;
}
.stat-card:hover { transform: translateY(-4px); box-shadow: 0 12px 40px rgba(0,180,216,0.1); }
.stat-number {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--cyan), var(--electric-blue));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 0.4rem;
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

/* ── Nav Cards (home page) ── */
.nav-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}
.nav-card {
  display: block;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: 1.5rem;
  text-decoration: none;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}
.nav-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0, 245, 212, 0.5), transparent);
  opacity: 0;
  transition: opacity var(--transition-base);
}
.nav-card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(0, 245, 212, 0.3);
  transform: translateY(-4px);
  box-shadow: 0 8px 40px rgba(0, 180, 216, 0.12);
}
.nav-card:hover::before { opacity: 1; }
.nav-card-icon {
  font-size: 2.2rem;
  display: block;
  margin-bottom: 0.75rem;
}
.nav-card-title {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--cyan);
  margin-bottom: 0.5rem;
}
.nav-card-desc {
  font-size: 0.87rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ============================================================
   PROSE (article content)
   ============================================================ */
.prose {
  max-width: 780px;
}
.prose p {
  margin-bottom: 1.25rem;
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1.85;
}
.prose p:last-child { margin-bottom: 0; }
.prose strong { color: var(--text-primary); font-weight: 600; }
.prose em { color: var(--text-muted); font-style: italic; }
.prose a { color: var(--electric-blue); text-decoration: none; border-bottom: 1px solid rgba(0,180,216,0.3); transition: all 0.2s; }
.prose a:hover { color: var(--cyan); border-color: var(--cyan); }

.prose h2 {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
  margin: 2.5rem 0 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-subtle);
}
.prose h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--cyan);
  margin: 1.75rem 0 0.5rem;
}
.prose h4 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 600;
  color: var(--electric-blue);
  margin: 1.25rem 0 0.4rem;
}

.prose ul, .prose ol {
  margin: 0.75rem 0 1.25rem;
  padding-left: 1.5rem;
  color: var(--text-muted);
}
.prose li {
  margin-bottom: 0.4rem;
  font-size: 0.97rem;
  line-height: 1.75;
}
.prose li strong { color: var(--text-primary); }

/* ── Blockquotes ── */
.prose blockquote {
  margin: 2rem 0;
  padding: 1.5rem 1.5rem 1.5rem 2.5rem;
  border-left: 3px solid var(--cyan);
  background: rgba(0, 245, 212, 0.04);
  border-radius: 0 8px 8px 0;
  font-style: italic;
  color: var(--text-muted);
}
.prose blockquote p { margin-bottom: 0.5rem; }
.prose blockquote cite {
  display: block;
  margin-top: 0.5rem;
  font-style: normal;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--cyan);
  opacity: 0.8;
  letter-spacing: 0.08em;
}

/* ── Code / Mono ── */
.prose code {
  font-family: var(--font-mono);
  font-size: 0.87em;
  color: var(--cyan);
  background: rgba(0, 245, 212, 0.07);
  border: 1px solid rgba(0, 245, 212, 0.12);
  border-radius: 4px;
  padding: 0.1em 0.45em;
}

/* ── Science term highlight ── */
.quantum-term {
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: var(--violet);
  background: rgba(157, 78, 221, 0.07);
  border: 1px solid rgba(157, 78, 221, 0.15);
  border-radius: 4px;
  padding: 0.1em 0.45em;
  white-space: nowrap;
}

/* ── Callout boxes ── */
.callout {
  margin: 2rem 0;
  padding: 1.25rem 1.5rem;
  border-radius: 8px;
  border: 1px solid var(--border-subtle);
  position: relative;
  overflow: hidden;
}
.callout::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 3px;
}
.callout-blue { background: rgba(0, 180, 216, 0.05); border-color: rgba(0, 180, 216, 0.2); }
.callout-blue::before { background: var(--electric-blue); }
.callout-purple { background: rgba(157, 78, 221, 0.05); border-color: rgba(157, 78, 221, 0.2); }
.callout-purple::before { background: var(--violet); }
.callout-gold { background: rgba(255, 215, 0, 0.04); border-color: rgba(255, 215, 0, 0.2); }
.callout-gold::before { background: var(--quantum-gold); }
.callout-cyan { background: rgba(0, 245, 212, 0.04); border-color: rgba(0, 245, 212, 0.2); }
.callout-cyan::before { background: var(--cyan); }

.callout-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--electric-blue);
  margin-bottom: 0.6rem;
}
.callout-purple .callout-title { color: var(--violet); }
.callout-gold .callout-title { color: var(--quantum-gold); }
.callout-cyan .callout-title { color: var(--cyan); }

.callout p { font-size: 0.93rem; color: var(--text-muted); margin: 0; line-height: 1.7; }
.callout p strong { color: var(--text-primary); }

/* ── Key findings box ── */
.finding-box {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 10px;
  padding: 2rem;
  margin: 2rem 0;
}
.finding-box h3 {
  font-family: var(--font-display);
  font-size: 1rem;
  color: var(--cyan);
  margin-bottom: 1rem;
}
.finding-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  list-style: none;
  padding: 0;
}
.finding-list li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  font-size: 0.93rem;
  color: var(--text-muted);
  line-height: 1.6;
}
.finding-list li::before {
  content: '▸';
  color: var(--electric-blue);
  flex-shrink: 0;
  margin-top: 0.1rem;
  font-size: 0.8rem;
}

/* ── Timeline ── */
.timeline {
  position: relative;
  padding-left: 2rem;
  margin: 2rem 0;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.5rem;
  bottom: 0;
  width: 1px;
  background: linear-gradient(180deg, var(--electric-blue), transparent);
  opacity: 0.4;
}
.timeline-item {
  position: relative;
  margin-bottom: 1.75rem;
}
.timeline-item::before {
  content: '';
  position: absolute;
  left: -2.4rem;
  top: 0.35rem;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--electric-blue);
  box-shadow: 0 0 8px rgba(0, 180, 216, 0.6);
}
.timeline-year {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--electric-blue);
  letter-spacing: 0.1em;
  margin-bottom: 0.25rem;
}
.timeline-content {
  font-size: 0.93rem;
  color: var(--text-muted);
  line-height: 1.65;
}
.timeline-content strong { color: var(--text-primary); }

/* ── Interpretations ── */
.interpretation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}
.interpretation-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 1.25rem;
  transition: all 0.3s;
}
.interpretation-card:hover {
  border-color: rgba(157, 78, 221, 0.3);
  box-shadow: 0 4px 20px rgba(157, 78, 221, 0.08);
}
.interp-name {
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--violet);
  margin-bottom: 0.4rem;
}
.interp-body {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ── Misconception box ── */
.misconception-box {
  background: rgba(255, 107, 53, 0.04);
  border: 1px solid rgba(255, 107, 53, 0.15);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}
.misconception-box .ms-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #ff6b35;
  margin-bottom: 0.75rem;
}
.misconception-item {
  display: flex;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}
.misconception-item:last-child { margin-bottom: 0; }
.ms-cross { color: #ff6b35; flex-shrink: 0; }
.ms-check { color: var(--cyan); flex-shrink: 0; }
.ms-text { color: var(--text-muted); line-height: 1.6; }

/* ── Reveal animation ── */
.reveal {
  opacity: 1;
  transform: translateY(0);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================================
   REFERENCES PAGE
   ============================================================ */
.ref-section { margin-bottom: 3rem; }
.ref-section-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--cyan);
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.ref-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}
.ref-item {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  transition: border-color 0.2s;
}
.ref-item:hover { border-color: rgba(0, 180, 216, 0.25); }
.ref-authors {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dim);
  letter-spacing: 0.04em;
  margin-bottom: 0.25rem;
}
.ref-title {
  font-family: var(--font-body);
  font-size: 0.93rem;
  color: var(--text-primary);
  font-weight: 500;
  margin-bottom: 0.25rem;
  font-style: italic;
}
.ref-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--electric-blue);
  letter-spacing: 0.04em;
}
.ref-link {
  color: var(--electric-blue);
  text-decoration: none;
  border-bottom: 1px solid rgba(0,180,216,0.3);
  transition: color 0.2s;
}
.ref-link:hover { color: var(--cyan); }

/* ── Search filter ── */
.ref-search-wrapper {
  margin-bottom: 2.5rem;
  position: relative;
}
.ref-search {
  width: 100%;
  max-width: 480px;
  padding: 0.7rem 1rem 0.7rem 2.5rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: 8px;
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 0.9rem;
  transition: border-color 0.2s;
}
.ref-search:focus { outline: none; border-color: var(--electric-blue); }
.ref-search::placeholder { color: var(--text-dim); }
.ref-search-icon {
  position: absolute;
  left: 0.75rem;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-dim);
  font-size: 0.85rem;
  pointer-events: none;
}

/* ============================================================
   ANIMATIONS
   ============================================================ */
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-10px); }
}
@keyframes pulse-glow {
  0%, 100% { filter: brightness(1) drop-shadow(0 0 8px rgba(0,245,212,0.4)); }
  50%       { filter: brightness(1.2) drop-shadow(0 0 20px rgba(0,245,212,0.7)); }
}
@keyframes pulse-gold {
  0%, 100% { box-shadow: 0 0 8px rgba(255,215,0,0.2); }
  50%       { box-shadow: 0 0 20px rgba(255,215,0,0.4); }
}
@keyframes scan-line {
  0%   { top: -5%; opacity: 0; }
  20%  { opacity: 1; }
  80%  { opacity: 1; }
  100% { top: 105%; opacity: 0; }
}
@keyframes particle-drift {
  0%   { transform: translate(0, 0) scale(1); opacity: 0.6; }
  100% { transform: translate(20px, -30px) scale(0.5); opacity: 0; }
}

/* ── Wave separator ── */
.wave-sep {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--electric-blue), transparent);
  margin: 3rem 0;
  opacity: 0.2;
}

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 900px) {
  .card-grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr; gap: 2rem; }
  .footer-nav-cols { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 680px) {
  .hero { padding: 4rem 0 3rem; }
  .hero-title { font-size: 2rem; }
  .hero-subtitle { font-size: 1rem; }
  .card-grid, .card-grid-2, .card-grid-3 { grid-template-columns: 1fr; }
  .nav-cards { grid-template-columns: 1fr; }
  .interpretation-grid { grid-template-columns: 1fr; }
  .mobile-back-btn { display: block; }
  .hamburger { display: flex; }
  .quantum-nav { display: none; }
  .site-logo .logo-sub { display: none; }
  .footer-nav-cols { grid-template-columns: 1fr 1fr; }
  .page-header h1 { font-size: 1.75rem; }
  .prose h2 { font-size: 1.25rem; }
}

@media (max-width: 480px) {
  .footer-nav-cols { grid-template-columns: 1fr; }
  .hero-img-placeholder { aspect-ratio: 4/3; }
  .stat-number { font-size: 2rem; }
}

/* Nav compact: BotBuhdy home icon */
.nav-home-link { opacity: 0.6; padding: 6px 8px !important; min-width: auto; }
.nav-home-link:hover { opacity: 1; }
/* Tighter nav spacing */
.nav-link { padding: 8px 10px; font-size: 0.78rem; white-space: nowrap; }