/* ======================
   CSS Reset & Base Styles
   ====================== */

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

:root {
  /* Primary Colors - Deep medical Blue & Green */
  --color-primary: #1E3A8A;
  --color-primary-dark: #1E40AF;
  --color-secondary: #10B981;
  --color-secondary-dark: #059669;  
  --color-secondary-light: #34D399;
  --white-background: white;
  
  /* Neutrals */
  --color-neutral-50: #F8FAFC;
  --color-neutral-100: #F1F5F9;
  --color-neutral-200: #E2E8F0;
  --color-neutral-300: #CBD5E1;
  --color-neutral-400: #94A3B8;
  --color-neutral-500: #64748B;
  --color-neutral-600: #475569;
  --color-neutral-700: #334155;
  --color-neutral-800: #1E293B;
  --color-neutral-900: #0F172A;
  
  /* Semantic Colors */
  --color-text-primary: var(--color-neutral-900);
  --color-text-secondary: var(--color-neutral-600);
  --color-text-muted: var(--color-neutral-500);
  --color-background: #FFFFFF;
  --color-background-soft: var(--color-neutral-50);
  --color-background-muted: var(--color-neutral-100);
  --color-border: var(--color-neutral-200);
  --color-success: #10B981;
  --color-warning: #F59E0B;
  --color-error: #EF4444;
  
  /* Shadows */
  --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);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  
  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  --spacing-4xl: 6rem;
  
  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;
  
  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  --font-serif: 'Georgia', 'Times New Roman', serif;
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-background);
  overflow-x: hidden;
}

/* ======================
   Typography Scale
   ====================== */

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-text-primary);
}

h1 {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  letter-spacing: -0.02em;
}

h2 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  letter-spacing: -0.01em;
}

h3 {
  font-size: clamp(1.5rem, 3vw, 2rem);
}

h4 {
  font-size: 1.5rem;
}

h5 {
  font-size: 1.25rem;
}

h6 {
  font-size: 1.125rem;
}

p {
  margin: 0 0 1rem;
  color: var(--color-text-secondary);
  line-height: 1.7;
}

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

a:hover {
  color: var(--color-primary-dark);
}

/* ======================
   Layout Utilities
   ====================== */

.container {
  width: 100%;
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 var(--spacing-xl);
}

section {
  padding: var(--spacing-4xl) 0;
}

/* ======================
   Component Patterns
   ====================== */

.section-title {
  text-align: center;
  margin-bottom: var(--spacing-3xl);
  color: var(--color-text-primary);
  position: relative;
  padding-bottom: var(--spacing-lg);
}

.section-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 4px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
  border-radius: var(--radius-full);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: 0.875rem 1.75rem;
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.5;
  text-decoration: none;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  background: white;
  border: 2px solid var(--color-primary);
}

.btn-secondary {
  background: white;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
  background: var(--color-primary);
  color: white;
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.btn-ghost:hover {
  background: var(--color-background-soft);
  border-color: var(--color-primary);
}

/* ======================
   Card Styles
   ====================== */

.card {
  background: white;
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-md);
  transition: all var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
}

/* ======================
   Animations
   ====================== */

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

.transition-item {
  opacity: 0;
  animation: fadeIn 0.6s ease forwards;
}

.transition-item[data-delay="100"] { animation-delay: 0.1s; }
.transition-item[data-delay="200"] { animation-delay: 0.2s; }
.transition-item[data-delay="300"] { animation-delay: 0.3s; }
.transition-item[data-delay="400"] { animation-delay: 0.4s; }
.transition-item[data-delay="500"] { animation-delay: 0.5s; }

/* ======================
   Responsive Utilities
   ====================== */

@media (max-width: 768px) {
  :root {
    --spacing-4xl: 3rem;
    --spacing-3xl: 2.5rem;
  }
  
  .container {
    padding: 0 var(--spacing-md);
  }
  
  section {
    padding: var(--spacing-3xl) 0;
  }
}

/* ======================
   Accessibility
   ====================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}