/**
 * Design Tokens - Single Source of Truth
 * Sử dụng cho toàn bộ DID Use Case project
 */

:root {
  /* ============================================
     SPACING SCALE (Based on 4px grid)
     ============================================ */
  --space-0: 0;
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;

  /* ============================================
     TYPOGRAPHY
     ============================================ */
  --font-family-base: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Courier New', monospace;

  /* Font Sizes */
  --text-xs: 0.75rem;    /* 12px */
  --text-sm: 0.875rem;   /* 14px */
  --text-base: 1rem;     /* 16px */
  --text-lg: 1.125rem;   /* 18px */
  --text-xl: 1.25rem;    /* 20px */
  --text-2xl: 1.5rem;    /* 24px */
  --text-3xl: 2rem;      /* 32px */

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

  /* Line Heights */
  --leading-none: 1;
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.75;

  /* Letter Spacing */
  --tracking-tight: -0.025em;
  --tracking-normal: 0;
  --tracking-wide: 0.025em;
  --tracking-wider: 0.05em;

  /* ============================================
     BORDER RADIUS
     ============================================ */
  --radius-none: 0;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 24px;
  --radius-full: 9999px;

  /* ============================================
     SHADOWS
     ============================================ */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.15);
  --shadow-2xl: 0 25px 50px rgba(0, 0, 0, 0.25);

  /* ============================================
     TRANSITIONS
     ============================================ */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
  --transition-slower: 500ms ease;

  /* Easing functions */
  --ease-in: cubic-bezier(0.4, 0, 1, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);

  /* ============================================
     Z-INDEX SCALE
     ============================================ */
  --z-base: 1;
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 900;
  --z-modal: 1000;
  --z-popover: 1100;
  --z-tooltip: 1200;

  /* ============================================
     LAYOUT DIMENSIONS
     ============================================ */
  --mobile-width: 375px;
  --mobile-height: 812px;
  --desktop-max-width: 800px;

  /* Touch targets (Accessibility) */
  --touch-target-min: 44px;

  /* ============================================
     NEUTRAL COLORS (Global)
     ============================================ */
  --white: #ffffff;
  --black: #000000;

  /* Grays */
  --gray-50: #fafafa;
  --gray-100: #f5f5f5;
  --gray-200: #e5e5e5;
  --gray-300: #d4d4d4;
  --gray-400: #a3a3a3;
  --gray-500: #737373;
  --gray-600: #525252;
  --gray-700: #404040;
  --gray-800: #262626;
  --gray-900: #171717;

  /* ============================================
     SEMANTIC COLORS
     ============================================ */
  /* Success */
  --success-50: #f0fdf4;
  --success-100: #dcfce7;
  --success-500: #22c55e;
  --success-600: #16a34a;
  --success-700: #15803d;

  /* Error */
  --error-50: #fef2f2;
  --error-100: #fee2e2;
  --error-500: #ef4444;
  --error-600: #dc2626;
  --error-700: #b91c1c;

  /* Warning */
  --warning-50: #fffbeb;
  --warning-100: #fef3c7;
  --warning-500: #f59e0b;
  --warning-600: #d97706;
  --warning-700: #b45309;

  /* Info */
  --info-50: #eff6ff;
  --info-100: #dbeafe;
  --info-500: #3b82f6;
  --info-600: #2563eb;
  --info-700: #1d4ed8;

  /* ============================================
     FOCUS STATES (Accessibility)
     ============================================ */
  --focus-ring-width: 3px;
  --focus-ring-offset: 2px;
  --focus-ring-color: #0066cc;

  /* ============================================
     BREAKPOINTS (for reference in JS)
     ============================================ */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
}

/**
 * Dark Mode Support (Optional - Future)
 */
@media (prefers-color-scheme: dark) {
  :root {
    /* Override tokens here when implementing dark mode */
  }
}

/**
 * Reduced Motion (Accessibility)
 */
@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0ms;
    --transition-base: 0ms;
    --transition-slow: 0ms;
    --transition-slower: 0ms;
  }
}