/* ========== CSS VARIABLES & RESET ========== */
:root {
  --navy: #0a1628;
  --navy-light: #132040;
  --navy-mid: #1a2d54;
  --blue-accent: #3b82f6;
  --blue-glow: #60a5fa;
  --white: #ffffff;
  --gray-50: #f8fafc;
  --gray-100: #f1f5f9;
  --gray-200: #e2e8f0;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --font-heading: 'Outfit', sans-serif;
  --font-body: 'Inter', sans-serif;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  color: var(--text-primary);
  background: var(--white);
  line-height: 1.7;
  overflow-x: hidden;
}

/* ========== TYPOGRAPHY ========== */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
}

h1 { font-size: clamp(2.2rem, 5vw, 3.5rem); }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.4rem); }
h3 { font-size: clamp(1.2rem, 2.5vw, 1.6rem); }
h4 { font-size: 1.1rem; }

p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  max-width: 72ch;
}

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

a:hover { color: var(--blue-glow); }

/* ========== ACCESSIBILITY ========== */
:focus-visible {
  outline: 2px solid var(--blue-accent);
  outline-offset: 4px;
}

.back-to-top:focus-visible {
  outline-offset: 2px;
}

/* ========== NAVIGATION ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: rgba(10, 22, 40, 0.92);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(59, 130, 246, 0.08);
  transition: var(--transition);
}

.navbar.scrolled {
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.15);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  height: 70px;
}

.nav-logo {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: -0.02em;
}

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

.nav-links {
  display: flex;
  list-style: none;
  gap: 0.25rem;
}

.nav-links a {
  color: var(--gray-400);
  font-size: 0.88rem;
  font-weight: 500;
  padding: 0.5rem 0.9rem;
  border-radius: 8px;
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--white);
  background: rgba(59, 130, 246, 0.12);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 4px;
}

.hamburger span {
  width: 24px;
  height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: var(--transition);
}

/* ========== HERO SECTION ========== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(150deg, var(--navy) 0%, var(--navy-light) 50%, var(--navy-mid) 100%);
  position: relative;
  overflow: hidden;
  padding: 6rem 2rem 4rem;
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, rgba(59, 130, 246, 0.08) 0%, transparent 70%);
  border-radius: 50%;
  animation: float 12s ease-in-out infinite;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: -30%;
  left: -10%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(96, 165, 250, 0.06) 0%, transparent 70%);
  border-radius: 50%;
  animation: float 15s ease-in-out infinite reverse;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0); }
  50% { transform: translate(30px, -40px); }
}

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

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: rgba(59, 130, 246, 0.12);
  border: 1px solid rgba(59, 130, 246, 0.2);
  padding: 0.4rem 1.2rem;
  border-radius: 50px;
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--blue-glow);
  margin-bottom: 1.5rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hero h1 {
  color: var(--white);
  margin-bottom: 1.5rem;
}

.hero h1 em {
  font-style: normal;
  background: linear-gradient(135deg, var(--blue-accent), var(--blue-glow));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  color: var(--gray-400) !important;
  font-size: 1.15rem !important;
  margin: 0 auto 2.5rem;
  max-width: 600px;
}

.hero-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--blue-accent);
  color: var(--white);
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.85rem 2rem;
  border-radius: 12px;
  transition: var(--transition);
  border: none;
  cursor: pointer;
}

.hero-cta:hover {
  background: var(--blue-glow);
  color: var(--navy);
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(59, 130, 246, 0.3);
}

.scroll-indicator {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  color: var(--gray-500);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  animation: bounce 2s ease-in-out infinite;
}

@keyframes bounce {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

/* ========== SECTIONS ========== */
.section {
  padding: 6rem 2rem;
}

.section-alt {
  background: var(--gray-50);
}

.section-dark {
  background: var(--navy);
  color: var(--white);
}

.section-dark p {
  color: var(--gray-400);
}

.section-dark h2 {
  color: var(--white);
}

.container {
  max-width: 1100px;
  margin: 0 auto;
}

.section-header {
  text-align: center;
  margin-bottom: 4rem;
}

.section-label {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blue-accent);
  margin-bottom: 0.75rem;
}

.section-header h2 {
  margin-bottom: 1rem;
}

.section-header p {
  margin: 0 auto;
  color: var(--text-muted);
}

.section-dark .section-header p {
  color: var(--gray-400);
}

/* ========== CARDS ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: 16px;
  padding: 2rem;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--blue-accent), var(--blue-glow));
  opacity: 0;
  transition: var(--transition);
}

.card:hover {
  border-color: rgba(59, 130, 246, 0.2);
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(10, 22, 40, 0.08);
}

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

.card-icon {
  width: 48px;
  height: 48px;
  background: rgba(59, 130, 246, 0.08);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  margin-bottom: 1.25rem;
}

.card h4 {
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.card p {
  font-size: 0.95rem;
  color: var(--text-muted);
}

/* Dark cards */
.card-dark {
  background: var(--navy-light);
  border-color: rgba(59, 130, 246, 0.1);
}

.card-dark h4 { color: var(--white); }
.card-dark p { color: var(--gray-400); }

.card-dark:hover {
  border-color: rgba(59, 130, 246, 0.25);
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.2);
}

/* ========== DIAGRAMS ========== */
.diagram-container {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: 16px;
  padding: 2.5rem;
  margin: 2rem 0;
  text-align: center;
}

.diagram-container h3 {
  margin-bottom: 0.5rem;
}

.diagram-caption {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

.diagram-svg {
  width: 100%;
  max-width: 600px;
  margin: 0 auto;
  display: block;
}

.diagram-dark {
  background: var(--navy-light);
  border-color: rgba(59, 130, 246, 0.1);
}

.diagram-dark h3 { color: var(--white); }
.diagram-dark .diagram-caption { color: var(--gray-400); }

/* ========== TWO COLUMN LAYOUT ========== */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.two-col-text h3 {
  margin-bottom: 1rem;
  color: var(--text-primary);
}

.two-col-text p {
  margin-bottom: 1rem;
}

/* ========== CONDITIONING TYPES ========== */
.conditioning-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
  margin-top: 2rem;
}

.conditioning-card {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: 16px;
  padding: 2rem;
  text-align: center;
  transition: var(--transition);
}

.conditioning-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(10, 22, 40, 0.08);
  border-color: rgba(59, 130, 246, 0.2);
}

.conditioning-number {
  width: 40px;
  height: 40px;
  background: var(--blue-accent);
  color: var(--white);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1rem;
  margin: 0 auto 1rem;
}

.conditioning-card h4 {
  margin-bottom: 0.75rem;
}

.conditioning-card p {
  font-size: 0.92rem;
  color: var(--text-muted);
  margin: 0 auto;
}

/* ========== EFFECTS LIST ========== */
.effects-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

.effect-item {
  display: flex;
  gap: 1rem;
  padding: 1.5rem;
  background: var(--navy-light);
  border: 1px solid rgba(59, 130, 246, 0.1);
  border-radius: 14px;
  transition: var(--transition);
}

.effect-item:hover {
  border-color: rgba(59, 130, 246, 0.25);
  transform: translateY(-2px);
}

.effect-icon {
  width: 44px;
  height: 44px;
  min-width: 44px;
  background: rgba(59, 130, 246, 0.12);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.effect-text h4 {
  color: var(--white);
  margin-bottom: 0.4rem;
  font-size: 1rem;
}

.effect-text p {
  font-size: 0.9rem;
  color: var(--gray-400);
}

/* ========== ETHICS SECTION ========== */
.ethics-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  margin-top: 2rem;
}

.ethics-item {
  display: flex;
  gap: 1.25rem;
  padding: 1.75rem;
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: 14px;
  transition: var(--transition);
  align-items: flex-start;
}

.ethics-item:hover {
  border-color: rgba(59, 130, 246, 0.2);
  box-shadow: 0 8px 30px rgba(10, 22, 40, 0.06);
}

.ethics-marker {
  width: 44px;
  height: 44px;
  min-width: 44px;
  background: rgba(59, 130, 246, 0.08);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
}

.ethics-content h4 {
  margin-bottom: 0.4rem;
}

.ethics-content p {
  font-size: 0.93rem;
  color: var(--text-muted);
}

/* ========== CASE STUDIES ========== */
.case-study {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: 16px;
  padding: 2.5rem;
  margin-bottom: 1.5rem;
  transition: var(--transition);
}

.case-study:hover {
  border-color: rgba(59, 130, 246, 0.2);
  box-shadow: 0 8px 30px rgba(10, 22, 40, 0.06);
}

.case-study-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--blue-accent);
  background: rgba(59, 130, 246, 0.08);
  padding: 0.3rem 0.8rem;
  border-radius: 6px;
  margin-bottom: 1rem;
}

.case-study h4 {
  margin-bottom: 0.75rem;
  font-size: 1.2rem;
}

.case-study p {
  font-size: 0.95rem;
}

.case-study-source {
  margin-top: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  font-style: italic;
}

/* ========== CONCLUSION ========== */
.conclusion-content {
  text-align: center;
  max-width: 700px;
  margin: 0 auto;
}

.conclusion-content h2 {
  color: var(--white);
  margin-bottom: 1.5rem;
}

.conclusion-content > p {
  color: var(--gray-400);
  margin: 0 auto 2.5rem;
}

.key-findings {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  text-align: left;
  margin-bottom: 2.5rem;
}

.finding {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  background: rgba(59, 130, 246, 0.08);
  border: 1px solid rgba(59, 130, 246, 0.12);
  border-radius: 12px;
}

.finding-check {
  color: var(--blue-glow);
  font-size: 1.1rem;
  margin-top: 2px;
}

.finding p {
  font-size: 0.92rem;
  color: var(--gray-300);
}

.conclusion-note {
  font-size: 0.95rem;
  color: var(--gray-500);
  font-style: italic;
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

/* ========== FOOTER ========== */
.footer {
  background: var(--navy);
  border-top: 1px solid rgba(255, 255, 255, 0.06);
  padding: 2rem;
  text-align: center;
}

.footer p {
  color: var(--gray-500);
  font-size: 0.85rem;
  margin: 0 auto;
}

/* ========== ANIMATIONS ========== */
.animate-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.animate-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ========== MOBILE MENU ========== */
.mobile-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(10, 22, 40, 0.96);
  backdrop-filter: blur(20px);
  z-index: 999;
  justify-content: center;
  align-items: center;
}

.mobile-overlay.open {
  display: flex;
}

.mobile-nav {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  list-style: none;
}

.mobile-nav a {
  color: var(--gray-300);
  font-size: 1.2rem;
  font-weight: 500;
  padding: 0.75rem 2rem;
  border-radius: 10px;
  transition: var(--transition);
}

.mobile-nav a:hover {
  color: var(--white);
  background: rgba(59, 130, 246, 0.15);
}

.mobile-close {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  background: none;
  border: none;
  color: var(--white);
  font-size: 1.8rem;
  cursor: pointer;
}

/* ========== RESPONSIVE ========== */
@media (max-width: 900px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }

  .two-col {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

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

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

  .key-findings {
    grid-template-columns: 1fr;
  }

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

  .section {
    padding: 4rem 1.25rem;
  }

  .hero {
    padding: 5rem 1.25rem 3rem;
  }
}

/* ========== REFERENCES SECTION ========== */
.references-list {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  text-align: left;
  max-width: 900px;
  margin: 0 auto;
}

.reference-item {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
  padding-left: 1.5rem;
  text-indent: -1.5rem;
}

.section-dark .reference-item {
  color: var(--gray-400);
}

/* ========== BACK TO TOP ========== */
.back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  width: 44px;
  height: 44px;
  background: var(--blue-accent);
  color: var(--white);
  border: none;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  z-index: 99;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.3);
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
}

.back-to-top:hover {
  background: var(--blue-glow);
  transform: translateY(-4px);
  box-shadow: 0 8px 25px rgba(59, 130, 246, 0.4);
}

@media (max-width: 480px) {
  .hero-badge { font-size: 0.72rem; }
  .hero-cta { padding: 0.75rem 1.5rem; font-size: 0.9rem; }
  .section { padding: 3rem 1rem; }
}