/* ============================================
   Undercurrent Landing Page
   Colors derived from app theme (ocean blue + teal)
   ============================================ */

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

:root {
  --primary: #3b82f6;
  --primary-light: #93c5fd;
  --primary-dark: #2563eb;
  --secondary: #0891b2;
  --accent: #14b8a6;
  --accent-light: #99f6e4;

  --bg: #f8fafc;
  --surface: #ffffff;
  --surface-highlight: #ecfeff;

  --text: #1e293b;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;

  --border: #e2e8f0;
  --border-light: #f1f5f9;

  --symptom: #8b5cf6;
  --food: #10b981;
  --medication: #3b82f6;
  --action: #f59e0b;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;

  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 4px 12px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 8px 24px rgba(15, 23, 42, 0.1);
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  font-size: 16px;
}

/* ---- Layout ---- */

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

.narrow {
  max-width: 800px;
}

.center {
  text-align: center;
}

.section {
  padding: 96px 0;
}

.bg-surface {
  background: var(--surface);
}

/* ---- Navigation ---- */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(248, 250, 252, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 4px;
}

.logo-icon {
  flex-shrink: 0;
  border-radius: 6px;
}

.nav-links {
  display: flex;
  gap: 32px;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 15px;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* ---- Hero ---- */

.hero {
  padding: 160px 0 96px;
  background: linear-gradient(180deg, var(--surface-highlight) 0%, var(--bg) 100%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 48px;
  align-items: center;
}

.hero-content {
  text-align: left;
}

.hero h1 {
  font-size: clamp(36px, 5vw, 56px);
  font-weight: 700;
  line-height: 1.15;
  color: var(--text);
  margin-bottom: 24px;
  letter-spacing: -0.02em;
}

.hero-sub {
  font-size: clamp(17px, 2vw, 20px);
  color: var(--text-secondary);
  max-width: 540px;
  margin-bottom: 40px;
  line-height: 1.6;
}

.hero-cta {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.hero-note {
  font-size: 14px;
  color: var(--text-muted);
}

.hero-image img {
  max-width: 320px;
  height: auto;
  filter: drop-shadow(0 8px 24px rgba(59, 130, 246, 0.15));
}

/* ---- Buttons ---- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 28px;
  border-radius: var(--radius-md);
  font-size: 16px;
  font-weight: 600;
  text-decoration: none;
  transition: all 0.2s;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
  background: var(--primary-dark);
  box-shadow: 0 4px 16px rgba(59, 130, 246, 0.4);
  transform: translateY(-1px);
}

.btn-secondary {
  background: var(--surface);
  color: var(--text);
  border: 1.5px solid var(--border);
}

.btn-secondary:hover {
  border-color: var(--primary-light);
  color: var(--primary-dark);
  transform: translateY(-1px);
}

.btn-coming-soon {
  cursor: default;
  opacity: 0.9;
}

/* ---- Typography ---- */

h2 {
  font-size: clamp(28px, 3.5vw, 40px);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}

.lead {
  font-size: 18px;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}

.lead:last-child {
  margin-bottom: 0;
}

.lead.light {
  color: rgba(255, 255, 255, 0.8);
}

.section-intro {
  font-size: 18px;
  color: var(--text-secondary);
  max-width: 640px;
  margin-bottom: 56px;
}

.center .section-intro {
  margin-left: auto;
  margin-right: auto;
}

/* ---- Problem Section ---- */

.problem-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 64px;
  align-items: center;
  max-width: 900px;
  margin: 0 auto;
}

.problem-image img {
  max-width: 260px;
  height: auto;
  filter: drop-shadow(0 8px 24px rgba(59, 130, 246, 0.12));
}

.problem-content h2 {
  margin-bottom: 24px;
}

/* ---- Story Section ---- */

.story-section {
  background: linear-gradient(135deg, #fef3c7 0%, #fde68a 100%);
}

.story-card {
  background: var(--surface);
  border-radius: var(--radius-xl);
  padding: 48px;
  position: relative;
  box-shadow: var(--shadow-lg);
}

.story-quote {
  position: absolute;
  top: 20px;
  left: 32px;
  font-size: 120px;
  font-family: Georgia, serif;
  color: var(--primary-light);
  line-height: 1;
  opacity: 0.4;
  pointer-events: none;
}

.story-text {
  font-size: 18px;
  line-height: 1.8;
  color: var(--text);
  margin-bottom: 20px;
  position: relative;
  z-index: 1;
}

.story-text:last-of-type {
  margin-bottom: 24px;
}

.story-text em {
  color: var(--text-secondary);
}

.story-author {
  font-size: 15px;
  color: var(--text-muted);
  font-weight: 500;
}

.story-dash {
  color: var(--primary);
}

/* ---- Benefits Grid ---- */

.benefits-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.benefit-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: 32px;
  transition: box-shadow 0.2s, transform 0.2s;
}

.benefit-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.benefit-icon {
  width: 44px;
  height: 44px;
  background: var(--surface-highlight);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--primary);
}

.benefit-icon svg {
  width: 22px;
  height: 22px;
}

.benefit-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text);
}

.benefit-card p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.65;
  margin-bottom: 16px;
}

.benefit-card cite {
  font-style: normal;
  font-size: 13px;
  line-height: 1.8;
  display: block;
}

.benefit-card cite a {
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 1px solid var(--border-light);
  transition: color 0.2s, border-color 0.2s;
}

.benefit-card cite a:hover {
  color: var(--primary);
  border-color: var(--primary-light);
}

/* ---- Features Grid ---- */

.features-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 32px;
  margin-bottom: 56px;
}

.features-header-text {
  flex: 1;
}

.features-header-text .section-intro {
  margin-bottom: 0;
}

.features-header-image img {
  max-width: 220px;
  height: auto;
  filter: drop-shadow(0 8px 24px rgba(59, 130, 246, 0.12));
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
}

.feature h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.feature p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ---- Research Section ---- */

.research-header {
  display: flex;
  align-items: flex-start;
  gap: 32px;
  margin-bottom: 56px;
}

.research-header-image img {
  max-width: 180px;
  height: auto;
  filter: drop-shadow(0 8px 24px rgba(59, 130, 246, 0.12));
}

.research-header-text {
  flex: 1;
}

.research-header-text .section-intro {
  margin-bottom: 0;
}


/* ---- Privacy Section ---- */

.bg-dark {
  background: var(--text);
  color: #fff;
}

.bg-dark h2 {
  color: #fff;
}

.privacy-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 48px;
}

.privacy-header-text {
  flex: 1;
}

.privacy-header-image img {
  max-width: 180px;
  height: auto;
  filter: drop-shadow(0 8px 24px rgba(0, 0, 0, 0.3));
}

.privacy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px;
  margin-top: 48px;
}

.privacy-item h3 {
  font-size: 16px;
  font-weight: 600;
  color: var(--primary-light);
  margin-bottom: 8px;
}

.privacy-item p {
  font-size: 15px;
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.65;
}

.privacy-sources {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.privacy-sources p {
  font-size: 13px;
  color: rgba(255, 255, 255, 0.4);
  line-height: 1.8;
}

.privacy-sources a {
  color: rgba(255, 255, 255, 0.5);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  transition: color 0.2s, border-color 0.2s;
}

.privacy-sources a:hover {
  color: var(--primary-light);
  border-color: var(--primary-light);
}

/* ---- Audience Grid ---- */

.audience-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
  margin-top: 48px;
}

.audience-item h3 {
  font-size: 17px;
  font-weight: 600;
  margin-bottom: 8px;
}

.audience-item p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* ---- CTA Section ---- */

.bg-cta {
  background: linear-gradient(135deg, var(--surface-highlight) 0%, #ede9fe 100%);
}

.cta-image {
  margin-bottom: 24px;
}

.cta-image img {
  max-width: 200px;
  height: auto;
  filter: drop-shadow(0 8px 24px rgba(59, 130, 246, 0.15));
}

.bg-cta .hero-cta {
  justify-content: center;
}

.bg-cta h2 {
  margin-bottom: 16px;
}

.bg-cta .lead {
  margin-bottom: 32px;
}

/* ---- Footer ---- */

.footer {
  padding: 48px 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
}

.footer-brand {
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 4px;
}

.footer-disclaimer {
  font-size: 13px;
  color: var(--text-muted);
  max-width: 560px;
  line-height: 1.6;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  font-size: 14px;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

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

.footer-studio {
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border-light);
  font-size: 14px;
  color: var(--text-muted);
}

.footer-studio strong {
  color: var(--text-secondary);
  font-weight: 600;
}

.footer-studio .heart {
  color: #ef4444;
}

.footer-copyright {
  font-size: 13px;
  color: var(--text-muted);
}

/* ---- Responsive ---- */

@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    text-align: center;
    order: 2;
  }

  .hero-image {
    order: 1;
  }

  .hero-image img {
    max-width: 240px;
  }

  .hero-sub {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta {
    justify-content: center;
  }

  .problem-grid {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 32px;
  }

  .problem-image {
    order: 1;
  }

  .problem-content {
    order: 2;
  }

  .problem-image img {
    max-width: 200px;
  }

  .features-header {
    flex-direction: column;
    text-align: center;
  }

  .features-header-image {
    order: -1;
  }

  .features-header-image img {
    max-width: 180px;
  }

  .research-header {
    flex-direction: column;
    text-align: center;
  }

  .research-header-image {
    order: -1;
  }

  .research-header-image img {
    max-width: 150px;
  }

  .privacy-header {
    flex-direction: column;
    text-align: center;
  }

  .privacy-header-image {
    order: -1;
  }

  .privacy-header-image img {
    max-width: 150px;
  }
}

@media (max-width: 768px) {
  .section {
    padding: 64px 0;
  }

  .hero {
    padding: 120px 0 64px;
  }

  .nav-links {
    display: none;
  }

  .benefits-grid,
  .features-grid,
  .audience-grid {
    grid-template-columns: 1fr;
  }

  .privacy-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

  .btn {
    width: 100%;
    max-width: 300px;
  }

  .story-card {
    padding: 32px 24px;
  }

  .story-quote {
    font-size: 80px;
    top: 12px;
    left: 16px;
  }

  .story-text {
    font-size: 16px;
  }
}

@media (max-width: 480px) {
  .privacy-grid {
    grid-template-columns: 1fr;
  }

  .hero-image img {
    max-width: 180px;
  }

  .problem-image img,
  .features-header-image img,
  .research-header-image img,
  .privacy-header-image img,
  .cta-image img {
    max-width: 140px;
  }
}