/* CSS Reset */
*, *::before, *::after {
  box-sizing: border-box;
}

* {
  margin: 0;
  padding: 0;
}

/* CSS Variables */
:root {
  /* Colors */
  --color-primary: #1877F2;
  --color-primary-dark: #0D59C7;
  --color-primary-light: #4A99FF;
  --color-purple: #8B5CF6;
  --color-cyan: #06B6D4;
  --color-green: #10B981;
  --color-amber: #F59E0B;

  /* Neutrals */
  --color-white: #FFFFFF;
  --color-gray-50: #F9FAFB;
  --color-gray-100: #F3F4F6;
  --color-gray-200: #E5E7EB;
  --color-gray-400: #9CA3AF;
  --color-gray-600: #6B7280;
  --color-gray-700: #374151;
  --color-gray-900: #111827;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Spacing */
  --spacing-unit: 1rem;
  --container-max-width: 1200px;

  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.16);

  /* Border Radius */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
}

/* Base Styles */
html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-gray-700);
  background: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-gray-900);
  margin-bottom: 1rem;
}

h1 {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

h2 {
  font-size: 2.5rem;
}

h3 {
  font-size: 1.875rem;
  font-weight: 600;
}

h4 {
  font-size: 1.5rem;
  font-weight: 600;
}

p {
  margin-bottom: 1rem;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}

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

/* Sections */
section {
  padding: 5rem 0;
}

section:nth-child(even) {
  background: var(--color-gray-50);
}

/* Animations */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeIn 0.6s ease forwards;
}

/* Utilities */
.text-center {
  text-align: center;
}

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

/* Responsive Typography */
@media (max-width: 768px) {
  h1 {
    font-size: 2.25rem;
  }

  h2 {
    font-size: 1.875rem;
  }

  h3 {
    font-size: 1.5rem;
  }

  section {
    padding: 3rem 0;
  }
}