/* Lufi AI — Design System & Mobile-First Stylesheet (TASK-10.1) */

:root {
  --primary: #10b981;
  --primary-hover: #059669;
  --primary-light: #ecfdf5;
  --primary-glow: rgba(16, 185, 129, 0.2);
  --dark: #0f172a;
  --dark-surface: #1e293b;
  --text-main: #1e293b;
  --text-muted: #64748b;
  --text-light: #94a3b8;
  --bg-main: #ffffff;
  --bg-alt: #f8fafc;
  --bg-card: #ffffff;
  --border: #e2e8f0;
  --border-focus: #10b981;
  --success: #10b981;
  --warning: #f59e0b;
  --danger: #ef4444;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --transition: all 0.2s ease-in-out;
}

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

html {
  scroll-behavior: smooth;
  font-family: var(--font-sans);
  color: var(--text-main);
  background-color: var(--bg-main);
  -webkit-font-smoothing: antialiased;
}

body {
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: inherit;
  text-decoration: none;
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.25rem;
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--dark);
  letter-spacing: -0.5px;
}

.logo-badge {
  background: var(--primary);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.15rem 0.5rem;
  border-radius: var(--radius-full);
  text-transform: uppercase;
}

.nav-desktop {
  display: none;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.btn-mobile-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  padding: 10px;
}

.btn-mobile-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background-color: var(--dark);
  transition: var(--transition);
}

/* Mobile Menu Overlay */
.mobile-nav {
  display: none;
  position: absolute;
  top: 4.5rem;
  left: 0;
  width: 100%;
  background: #ffffff;
  border-bottom: 1px solid var(--border);
  box-shadow: var(--shadow-lg);
  padding: 1.5rem;
  flex-direction: column;
  gap: 1.25rem;
}

.mobile-nav.active {
  display: flex;
}

.mobile-nav a {
  font-size: 1.1rem;
  font-weight: 600;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: var(--transition);
  border: none;
  min-height: 48px;
  text-align: center;
}

.btn-primary {
  background-color: var(--primary);
  color: #ffffff;
  box-shadow: 0 4px 14px var(--primary-glow);
}

.btn-primary:hover {
  background-color: var(--primary-hover);
  transform: translateY(-1px);
}

.btn-secondary {
  background-color: var(--bg-alt);
  color: var(--dark);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background-color: #f1f5f9;
}

.btn-block {
  width: 100%;
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.35rem 0.85rem;
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  background: var(--primary-light);
  color: var(--primary-hover);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

/* Hero Section */
.hero {
  padding: 3.5rem 0 4rem;
  text-align: center;
  background: radial-gradient(circle at 50% 10%, rgba(16, 185, 129, 0.08) 0%, transparent 60%);
}

.hero h1 {
  font-size: 2.25rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--dark);
  margin: 1.25rem 0;
}

.hero h1 span {
  color: var(--primary);
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 650px;
  margin: 0 auto 2rem;
}

.hero-cta-group {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 400px;
  margin: 0 auto 2.5rem;
}

.hero-guarantee {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* Sections Base */
.section {
  padding: 4rem 0;
}

.section-alt {
  background-color: var(--bg-alt);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 3rem;
}

.section-header h2 {
  font-size: 1.85rem;
  font-weight: 800;
  color: var(--dark);
  letter-spacing: -0.02em;
  margin: 0.5rem 0;
}

.section-header p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

/* Feature Cards / Grid */
.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2rem 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: rgba(16, 185, 129, 0.3);
}

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--primary-light);
  color: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  margin-bottom: 1.25rem;
}

.card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--dark);
}

.card p {
  color: var(--text-muted);
  font-size: 0.975rem;
}

/* Medical Disclaimer Box */
.disclaimer-box {
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  margin: 2.5rem 0;
  display: flex;
  gap: 1rem;
  align-items: flex-start;
}

.disclaimer-box p {
  font-size: 0.9rem;
  color: #92400e;
  line-height: 1.5;
}

/* Pricing Grid */
.pricing-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  align-items: stretch;
}

.pricing-card {
  position: relative;
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem 1.5rem;
  display: flex;
  flex-direction: column;
  transition: var(--transition);
}

.pricing-card.featured {
  border-color: var(--primary);
  box-shadow: 0 10px 25px -5px var(--primary-glow);
}

.featured-badge {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--primary);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 0.25rem 0.85rem;
  border-radius: var(--radius-full);
  text-transform: uppercase;
}

.pricing-header h3 {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--dark);
}

.pricing-price {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--dark);
  margin: 1rem 0;
}

.pricing-price span {
  font-size: 1rem;
  color: var(--text-muted);
  font-weight: normal;
}

.pricing-features {
  list-style: none;
  margin: 1.5rem 0 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  flex-grow: 1;
}

.pricing-features li {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  color: var(--text-main);
}

.pricing-features li span {
  color: var(--primary);
  font-weight: bold;
}

/* FAQ Accordion */
.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.faq-item {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
}

.faq-question {
  width: 100%;
  padding: 1.25rem 1.5rem;
  text-align: left;
  background: none;
  border: none;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--dark);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.faq-answer {
  display: none;
  padding: 0 1.5rem 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

.faq-item.active .faq-answer {
  display: block;
}

.faq-item.active .faq-toggle {
  transform: rotate(180deg);
}

.faq-toggle {
  transition: var(--transition);
  font-size: 1.25rem;
}

/* Footer */
.footer {
  background: var(--dark);
  color: #fff;
  padding: 4rem 0 2rem;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2.5rem;
  margin-bottom: 3rem;
}

.footer-col h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: #fff;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  color: var(--text-light);
  font-size: 0.9rem;
  transition: var(--transition);
}

.footer-links a:hover {
  color: #fff;
}

.footer-bottom {
  border-top: 1px solid var(--dark-surface);
  padding-top: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--text-light);
}

/* Modal for Legal Pages */
.modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(15, 23, 42, 0.7);
  backdrop-filter: blur(4px);
  z-index: 100;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.modal-overlay.active {
  display: flex;
}

.modal-content {
  background: #ffffff;
  border-radius: var(--radius-lg);
  max-width: 650px;
  width: 100%;
  max-height: 85vh;
  overflow-y: auto;
  padding: 2rem;
  position: relative;
  box-shadow: var(--shadow-lg);
}

.modal-close {
  position: absolute;
  top: 1.25rem;
  right: 1.25rem;
  background: transparent;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
}

.modal-body h3 {
  margin: 1.5rem 0 0.5rem;
  font-size: 1.15rem;
  color: var(--dark);
}

.modal-body p {
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

/* Responsive Media Queries (Mobile-first -> Tablet / Desktop) */
@media (min-width: 640px) {
  .hero-cta-group {
    flex-direction: row;
    justify-content: center;
    max-width: 480px;
  }
}

@media (min-width: 768px) {
  .hero h1 {
    font-size: 3.25rem;
  }
  
  .grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .pricing-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr;
  }

  .footer-bottom {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }
}

@media (min-width: 1024px) {
  .btn-mobile-toggle {
    display: none;
  }

  .nav-desktop {
    display: flex;
    align-items: center;
    gap: 2rem;
  }

  .nav-desktop a {
    font-size: 0.95rem;
    font-weight: 600;
    color: var(--text-main);
    transition: var(--transition);
  }

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