/* CSS Custom Properties (Variables) */
:root {
  /* Colors - Light Theme */
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --secondary-color: #64748b;
  --accent-color: #06b6d4;
  
  --background-color: #ffffff;
  --surface-color: #f8fafc;
  --surface-hover: #f1f5f9;
  
  --text-primary: #0f172a;
  --text-secondary: #64748b;
  --text-muted: #94a3b8;
  
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;
  
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --error-color: #ef4444;
  
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  --font-mono: 'Fira Code', 'Consolas', 'Monaco', 'Liberation Mono', 'Lucida Console', monospace;
  
  --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-size-5xl: 3rem;      /* 48px */
  --font-size-6xl: 3.75rem;   /* 60px */
  
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  --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 */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */
  --space-32: 8rem;     /* 128px */
  
  /* Border Radius */
  --radius-sm: 0.125rem;  /* 2px */
  --radius-md: 0.375rem;  /* 6px */
  --radius-lg: 0.5rem;    /* 8px */
  --radius-xl: 0.75rem;   /* 12px */
  --radius-2xl: 1rem;     /* 16px */
  --radius-full: 9999px;
  
  /* Breakpoints */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
  --breakpoint-2xl: 1536px;
  
  /* Layout */
  --container-max-width: 1200px;
  --header-height: 70px;
  --footer-height: auto;
  
  /* Z-Index */
  --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-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  
  /* Animation */
  --animation-spin: spin 1s linear infinite;
  --animation-ping: ping 1s cubic-bezier(0, 0, 0.2, 1) infinite;
  --animation-pulse: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
  --animation-bounce: bounce 1s infinite;
}

/* Dark Theme */
[data-theme="dark"] {
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --secondary-color: #94a3b8;
  --accent-color: #06b6d4;
  
  --background-color: #0f172a;
  --surface-color: #1e293b;
  --surface-hover: #334155;
  
  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  
  --border-color: #334155;
  --border-hover: #475569;
  
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --error-color: #ef4444;
}

/* Auto theme based on system preference */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --primary-color: #3b82f6;
    --primary-hover: #2563eb;
    --secondary-color: #94a3b8;
    --accent-color: #06b6d4;
    
    --background-color: #0f172a;
    --surface-color: #1e293b;
    --surface-hover: #334155;
    
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    
    --border-color: #334155;
    --border-hover: #475569;
  }
}

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