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

:root {
    /* === COLOR TOKENS === */
    
    /* Primary Brand Colors */
    --color-primary: #00D9FF;
    --color-primary-hover: #00C4E6;
    --color-primary-rgb: 0, 217, 255;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #00D9FF 0%, #00A3CC 100%);
    --gradient-hero: linear-gradient(135deg, rgba(0, 217, 255, 0.1) 0%, rgba(0, 163, 204, 0.05) 100%);
    
    /* === TYPOGRAPHY === */
    --font-family-base: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    
    /* 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-size-5xl: 3rem;        /* 48px */
    --font-size-6xl: 3.75rem;     /* 60px */
    --font-size-7xl: 4.5rem;      /* 72px */
    
    /* Font Weights */
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --font-weight-extrabold: 800;
    --font-weight-black: 900;
    
    /* Line Heights */
    --line-height-tight: 1.2;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;
    
    /* === 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 */
    
    /* === LAYOUT === */
    --container-width: 1280px;
    --container-padding: var(--space-xl);
    --header-height: 80px;
    
    /* Border Radius */
    --radius-sm: 0.375rem;   /* 6px */
    --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);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    
    /* === ANIMATIONS === */
    --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);
    --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
    --ease-out: cubic-bezier(0.0, 0, 0.2, 1);
    --ease-in: cubic-bezier(0.4, 0, 1, 1);
    
    /* === Z-INDEX === */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal: 1040;
    --z-tooltip: 1050;
}

/* ============================================
   LIGHT THEME (Default)
   ============================================ */
:root,
[data-theme="light"] {
    /* Background Colors */
    --color-bg-primary: #FFFFFF;
    --color-bg-secondary: #F9FAFB;
    --color-bg-tertiary: #F3F4F6;
    
    /* Surface Colors */
    --color-surface: #FFFFFF;
    --color-surface-hover: #F9FAFB;
    --color-surface-elevated: #FFFFFF;
    
    /* Text Colors */
    --color-text-primary: #111827;
    --color-text-secondary: #6B7280;
    --color-text-tertiary: #9CA3AF;
    --color-text-inverse: #FFFFFF;
    
    /* Border Colors */
    --color-border: #E5E7EB;
    --color-border-hover: #D1D5DB;
    
    /* Shadows for Light Theme */
    --shadow-colored: 0 10px 40px -10px rgba(0, 217, 255, 0.2);
    --shadow-glow: 0 0 30px rgba(0, 217, 255, 0.3);
}

/* ============================================
   DARK THEME
   ============================================ */
[data-theme="dark"] {
    /* Background Colors */
    --color-bg-primary: #0A0E1A;
    --color-bg-secondary: #151923;
    --color-bg-tertiary: #1F242F;
    
    /* Surface Colors */
    --color-surface: #151923;
    --color-surface-hover: #1F242F;
    --color-surface-elevated: #252B3A;
    
    /* Text Colors */
    --color-text-primary: #F9FAFB;
    --color-text-secondary: #D1D5DB;
    --color-text-tertiary: #9CA3AF;
    --color-text-inverse: #111827;
    
    /* Border Colors */
    --color-border: #2D3748;
    --color-border-hover: #374151;
    
    /* Shadows for Dark Theme */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.5);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.7);
    --shadow-colored: 0 10px 40px -10px rgba(0, 217, 255, 0.4);
    --shadow-glow: 0 0 30px rgba(0, 217, 255, 0.5);
}

/* ============================================
   BREAKPOINTS (for reference in media queries)
   ============================================ */
/* 
   Mobile:  < 768px
   Tablet:  768px - 1024px
   Desktop: > 1024px
   
   Usage: @media (min-width: 768px) { ... }
*/