/* ============================================
   CSS Variables - Design System
   ============================================ */

:root {
  /* Colors - Primary Palette */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-primary-light: #3b82f6;

  /* Colors - Secondary */
  --color-secondary: #1f2937;
  --color-secondary-light: #374151;
  --color-accent: #06b6d4;
  --color-accent-light: #22d3ee;

  /* Colors - Neutrals */
  --color-bg: #ffffff;
  --color-bg-alt: #f9fafb;
  --color-bg-dark: #111827;
  --color-text: #374151;
  --color-text-light: #6b7280;
  --color-text-dark: #111827;
  --color-border: #e5e7eb;

  /* Colors - Semantic */
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-info: #3b82f6;

  /* Typography */
  --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Poppins', 'Inter', sans-serif;
  --font-mono: 'Fira Code', 'Courier New', monospace;

  /* Font Sizes */
  --fs-xs: 0.75rem;      /* 12px */
  --fs-sm: 0.875rem;     /* 14px */
  --fs-base: 1rem;       /* 16px */
  --fs-lg: 1.125rem;     /* 18px */
  --fs-xl: 1.25rem;      /* 20px */
  --fs-2xl: 1.5rem;      /* 24px */
  --fs-3xl: 1.875rem;    /* 30px */
  --fs-4xl: 2.25rem;     /* 36px */
  --fs-5xl: 3rem;        /* 48px */
  --fs-6xl: 3.75rem;     /* 60px */

  /* Font Weights */
  --fw-normal: 400;
  --fw-medium: 500;
  --fw-semibold: 600;
  --fw-bold: 700;
  --fw-extrabold: 800;

  /* Spacing */
  --space-xs: 0.25rem;   /* 4px */
  --space-sm: 0.5rem;    /* 8px */
  --space-md: 1rem;      /* 16px */
  --space-lg: 1.5rem;    /* 24px */
  --space-xl: 2rem;      /* 32px */
  --space-2xl: 3rem;     /* 48px */
  --space-3xl: 4rem;     /* 64px */
  --space-4xl: 6rem;     /* 96px */
  --space-5xl: 8rem;     /* 128px */

  /* Border Radius */
  --radius-sm: 0.25rem;  /* 4px */
  --radius-md: 0.5rem;   /* 8px */
  --radius-lg: 0.75rem;  /* 12px */
  --radius-xl: 1rem;     /* 16px */
  --radius-2xl: 1.5rem;  /* 24px */
  --radius-full: 9999px;

  /* 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);

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;

  /* Layout */
  --container-max-width: 1200px;
  --content-max-width: 800px;
  --header-height: 80px;

  /* Z-index */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* Reset & Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-primary);
  font-size: var(--fs-base);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: var(--fw-bold);
  line-height: 1.2;
  color: var(--color-text-dark);
}

a {
  text-decoration: none;
  color: inherit;
  transition: color var(--transition-base);
}

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

ul {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}