/* ===================================
   CSS VARIABLES - DESIGN SYSTEM
   =================================== */

:root {
  /* ===== COLOR PALETTE ===== */
  /* Primary Colors - Deep Purple/Blue */
  --color-primary-50: hsl(250, 70%, 95%);
  --color-primary-100: hsl(250, 70%, 90%);
  --color-primary-200: hsl(250, 70%, 80%);
  --color-primary-300: hsl(250, 70%, 70%);
  --color-primary-400: hsl(250, 70%, 60%);
  --color-primary-500: hsl(250, 70%, 50%);
  --color-primary-600: hsl(250, 70%, 40%);
  --color-primary-700: hsl(250, 70%, 30%);
  --color-primary-800: hsl(250, 70%, 20%);
  --color-primary-900: hsl(250, 70%, 10%);

  /* Accent Colors - Vibrant Cyan */
  --color-accent-50: hsl(185, 80%, 95%);
  --color-accent-100: hsl(185, 80%, 90%);
  --color-accent-200: hsl(185, 80%, 80%);
  --color-accent-300: hsl(185, 80%, 70%);
  --color-accent-400: hsl(185, 80%, 60%);
  --color-accent-500: hsl(185, 80%, 50%);
  --color-accent-600: hsl(185, 80%, 40%);
  --color-accent-700: hsl(185, 80%, 30%);

  /* Success, Warning, Error */
  --color-success: hsl(142, 71%, 45%);
  --color-warning: hsl(38, 92%, 50%);
  --color-error: hsl(0, 84%, 60%);

  /* Neutral Colors - Dark Theme */
  --color-bg-primary: hsl(240, 15%, 10%);
  --color-bg-secondary: hsl(240, 15%, 15%);
  --color-bg-tertiary: hsl(240, 15%, 20%);
  --color-bg-elevated: hsl(240, 15%, 25%);
  
  --color-text-primary: hsl(0, 0%, 95%);
  --color-text-secondary: hsl(0, 0%, 70%);
  --color-text-tertiary: hsl(0, 0%, 50%);
  --color-text-disabled: hsl(0, 0%, 35%);

  --color-border: hsla(0, 0%, 100%, 0.1);
  --color-border-hover: hsla(0, 0%, 100%, 0.2);
  --color-border-focus: var(--color-primary-400);

  /* Canvas specific */
  --color-canvas-bg: hsl(240, 15%, 18%);
  --color-canvas-grid: hsla(0, 0%, 100%, 0.05);
  
  /* ===== TYPOGRAPHY ===== */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'Fira Code', 'Courier New', monospace;
  
  /* 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: 2rem;      /* 32px */
  --font-size-4xl: 2.5rem;    /* 40px */

  /* 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-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* ===== SPACING ===== */
  --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 */

  /* ===== BORDERS & RADIUS ===== */
  --border-width-thin: 1px;
  --border-width-medium: 2px;
  --border-width-thick: 3px;

  --radius-sm: 0.375rem;   /* 6px */
  --radius-md: 0.5rem;     /* 8px */
  --radius-lg: 0.75rem;    /* 12px */
  --radius-xl: 1rem;       /* 16px */
  --radius-full: 9999px;

  /* ===== SHADOWS ===== */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5), 0 10px 10px -5px rgba(0, 0, 0, 0.3);
  --shadow-glow: 0 0 20px rgba(var(--color-primary-rgb), 0.3);

  /* Glassmorphism */
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-blur: blur(10px);

  /* ===== 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);

  /* ===== 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;

  /* ===== RESPONSIVE BREAKPOINTS ===== */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
  --breakpoint-2xl: 1536px;

  /* ===== LAYOUT ===== */
  --header-height: 64px;
  --sidebar-width: 280px;
  --property-panel-width: 320px;
  --toolbar-height: 56px;

  /* ===== CANVAS ===== */
  --canvas-width: 800px;
  --canvas-height: 1120px; /* A4 aspect ratio */
  --element-min-interaction: 44px; /* Touch target size */
}

/* ===== LIGHT MODE (Optional) ===== */
@media (prefers-color-scheme: light) {
  :root.light-mode {
    --color-bg-primary: hsl(0, 0%, 98%);
    --color-bg-secondary: hsl(0, 0%, 95%);
    --color-bg-tertiary: hsl(0, 0%, 92%);
    --color-bg-elevated: hsl(0, 0%, 100%);
    
    --color-text-primary: hsl(0, 0%, 10%);
    --color-text-secondary: hsl(0, 0%, 30%);
    --color-text-tertiary: hsl(0, 0%, 50%);
    --color-text-disabled: hsl(0, 0%, 65%);

    --color-border: hsla(0, 0%, 0%, 0.1);
    --color-border-hover: hsla(0, 0%, 0%, 0.2);

    --color-canvas-bg: hsl(0, 0%, 96%);
    --color-canvas-grid: hsla(0, 0%, 0%, 0.05);
  }
}