/**
 * BART Design System - Design Tokens
 * 
 * This file defines all design tokens (colors, typography, spacing, etc.) 
 * used throughout the BART application. Update these variables to change
 * the look and feel of the entire application.
 * 
 * @see docs/design-system.md for usage guidelines
 */

:root {
  /* ============================================
     Brand Colors
     ============================================ */
  --color-primary: #0d6efd;          /* Bootstrap blue */
  --color-primary-hover: #0b5ed7;
  --color-primary-light: #cfe2ff;
  
  --color-secondary: #6c757d;
  --color-secondary-hover: #5c636a;
  
  --color-success: #198754;
  --color-success-hover: #157347;
  --color-success-light: #d1e7dd;
  
  --color-warning: #ffc107;
  --color-warning-hover: #ffb300;
  --color-warning-light: #fff3cd;
  
  --color-danger: #dc3545;
  --color-danger-hover: #bb2d3b;
  --color-danger-light: #f8d7da;
  
  --color-info: #0dcaf0;
  --color-info-hover: #0aa2c0;
  --color-info-light: #cff4fc;

  /* ============================================
     Neutral/Gray Scale
     ============================================ */
  --color-white: #ffffff;
  --color-black: #000000;
  
  --color-gray-50: #f8f9fa;
  --color-gray-100: #e9ecef;
  --color-gray-200: #dee2e6;
  --color-gray-300: #ced4da;
  --color-gray-400: #adb5bd;
  --color-gray-500: #6c757d;
  --color-gray-600: #495057;
  --color-gray-700: #343a40;
  --color-gray-800: #212529;
  --color-gray-900: #0d0f11;

  /* ============================================
     Background Colors
     ============================================ */
  --bg-body: #ffffff;
  --bg-surface: #ffffff;
  --bg-hover: #f8f9fa;
  --bg-selected: #e9ecef;
  --bg-disabled: #e9ecef;

  /* ============================================
     Text Colors
     ============================================ */
  --text-primary: #212529;
  --text-secondary: #6c757d;
  --text-muted: #adb5bd;
  --text-disabled: #ced4da;
  --text-link: #0d6efd;
  --text-link-hover: #0b5ed7;

  /* ============================================
     Border Colors
     ============================================ */
  --border-color: #dee2e6;
  --border-color-light: #e9ecef;
  --border-color-dark: #ced4da;

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

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

  /* Font Weights */
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-snug: 1.375;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --line-height-loose: 2;

  /* ============================================
     Spacing Scale (based on 4px)
     ============================================ */
  --space-0: 0;
  --space-1: 0.25rem;    /* 4px */
  --space-2: 0.5rem;     /* 8px */
  --space-3: 0.75rem;    /* 12px */
  --space-4: 1rem;       /* 16px */
  --space-5: 1.25rem;    /* 20px */
  --space-6: 1.5rem;     /* 24px */
  --space-8: 2rem;       /* 32px */
  --space-10: 2.5rem;    /* 40px */
  --space-12: 3rem;      /* 48px */
  --space-16: 4rem;      /* 64px */
  --space-20: 5rem;      /* 80px */

  /* ============================================
     Border Radius
     ============================================ */
  --radius-none: 0;
  --radius-sm: 0.25rem;   /* 4px */
  --radius-md: 0.375rem;  /* 6px */
  --radius-lg: 0.5rem;    /* 8px */
  --radius-xl: 0.75rem;   /* 12px */
  --radius-2xl: 1rem;     /* 16px */
  --radius-full: 9999px;

  /* ============================================
     Shadows
     ============================================ */
  --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 
               0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --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);

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

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

  /* ============================================
     Breakpoints (for reference in JS)
     ============================================ */
  --breakpoint-xs: 0;
  --breakpoint-sm: 576px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 992px;
  --breakpoint-xl: 1200px;
  --breakpoint-xxl: 1400px;
}