frontend/src/css/variables.css

/* CSS Custom Properties for Theming */
:root {
  /* Color System - Primary (Burgundy) */
  --color-primary-50: #FFF5F5;
  --color-primary-100: #FFE4E4;
  --color-primary-200: #FFCCCC;
  --color-primary-300: #FFB3B3;
  --color-primary-400: #FF9999;
  --color-primary-500: #FF8080;
  --color-primary-600: #FF6666;
  --color-primary-700: #E65555;
  --color-primary-800: #CC4444;
  --color-primary-900: #910029;
  --color-primary-950: #6B0021;

  /* Color System - Secondary (Dark Gray) */
  --color-secondary-50: #F8F9FA;
  --color-secondary-100: #E9ECEF;
  --color-secondary-200: #DEE2E6;
  --color-secondary-300: #CED4DA;
  --color-secondary-400: #ADB5BD;
  --color-secondary-500: #6C757D;
  --color-secondary-600: #495057;
  --color-secondary-700: #343A40;
  --color-secondary-800: #212529;
  --color-secondary-900: #39404B;
  --color-secondary-950: #1A1E22;

  /* Color System - Accent (Light Blue-Gray) */
  --color-accent-50: #F8FAFC;
  --color-accent-100: #F1F5F9;
  --color-accent-200: #E2E8F0;
  --color-accent-300: #CBD5E1;
  --color-accent-400: #94A3B8;
  --color-accent-500: #64748B;
  --color-accent-600: #475569;
  --color-accent-700: #334155;
  --color-accent-800: #1E293B;
  --color-accent-900: #0F172A;
  --color-accent-950: #020617;

  /* Semantic Colors */
  --color-success: #22C55E;
  --color-success-50: #F0FDF4;
  --color-success-100: #DCFCE7;
  --color-success-200: #BBF7D0;
  --color-success-300: #86EFAC;
  --color-success-400: #4ADE80;
  --color-success-500: #22C55E;
  --color-success-600: #16A34A;
  --color-success-700: #15803D;
  --color-success-800: #166534;
  --color-success-900: #14532D;
  --color-success-950: #052E16;
  
  --color-warning: #F59E0B;
  --color-warning-50: #FFFBEB;
  --color-warning-100: #FEF3C7;
  --color-warning-200: #FDE68A;
  --color-warning-300: #FCD34D;
  --color-warning-400: #FBBF24;
  --color-warning-500: #F59E0B;
  --color-warning-600: #D97706;
  --color-warning-700: #B45309;
  --color-warning-800: #92400E;
  --color-warning-900: #78350F;
  --color-warning-950: #451A03;
  
  --color-error: #EF4444;
  --color-error-50: #FEF2F2;
  --color-error-100: #FEE2E2;
  --color-error-200: #FECACA;
  --color-error-300: #FCA5A5;
  --color-error-400: #F87171;
  --color-error-500: #EF4444;
  --color-error-600: #DC2626;
  --color-error-700: #B91C1C;
  --color-error-800: #991B1B;
  --color-error-900: #7F1D1D;
  --color-error-950: #450A0A;
  
  --color-info: #0EA5E9;
  --color-info-50: #F0F9FF;
  --color-info-100: #E0F2FE;
  --color-info-200: #BAE6FD;
  --color-info-300: #7DD3FC;
  --color-info-400: #38BDF8;
  --color-info-500: #0EA5E9;
  --color-info-600: #0284C7;
  --color-info-700: #0369A1;
  --color-info-800: #075985;
  --color-info-900: #0C4A6E;
  --color-info-950: #082F49;

  /* Typography System */
  --font-family-primary: 'Roboto', system-ui, sans-serif;
  --font-family-display: 'Pacifico', cursive;

  /* 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-size-8xl: 6rem;     /* 96px */
  --font-size-9xl: 8rem;     /* 128px */

  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;
  --line-height-loose: 2;

  /* Font Weights */
  --font-weight-thin: 100;
  --font-weight-extralight: 200;
  --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;

  /* Letter Spacing */
  --letter-spacing-tighter: -0.05em;
  --letter-spacing-tight: -0.025em;
  --letter-spacing-normal: 0em;
  --letter-spacing-wide: 0.025em;
  --letter-spacing-wider: 0.05em;
  --letter-spacing-widest: 0.1em;

  /* Spacing System */
  --spacing-px: 1px;
  --spacing-05: 0.125rem;  /* 2px */
  --spacing-1: 0.25rem;    /* 4px */
  --spacing-15: 0.375rem;  /* 6px */
  --spacing-2: 0.5rem;     /* 8px */
  --spacing-25: 0.625rem;  /* 10px */
  --spacing-3: 0.75rem;    /* 12px */
  --spacing-35: 0.875rem;  /* 14px */
  --spacing-4: 1rem;       /* 16px */
  --spacing-5: 1.25rem;    /* 20px */
  --spacing-6: 1.5rem;     /* 24px */
  --spacing-7: 1.75rem;    /* 28px */
  --spacing-8: 2rem;       /* 32px */
  --spacing-9: 2.25rem;    /* 36px */
  --spacing-10: 2.5rem;    /* 40px */
  --spacing-11: 2.75rem;   /* 44px */
  --spacing-12: 3rem;      /* 48px */
  --spacing-14: 3.5rem;    /* 56px */
  --spacing-16: 4rem;      /* 64px */
  --spacing-18: 4.5rem;    /* 72px */
  --spacing-20: 5rem;      /* 80px */
  --spacing-24: 6rem;      /* 96px */
  --spacing-28: 7rem;      /* 112px */
  --spacing-32: 8rem;      /* 128px */
  --spacing-36: 9rem;      /* 144px */
  --spacing-40: 10rem;     /* 160px */
  --spacing-44: 11rem;     /* 176px */
  --spacing-48: 12rem;     /* 192px */
  --spacing-52: 13rem;     /* 208px */
  --spacing-56: 14rem;     /* 224px */
  --spacing-60: 15rem;     /* 240px */
  --spacing-64: 16rem;     /* 256px */
  --spacing-72: 18rem;     /* 288px */
  --spacing-80: 20rem;     /* 320px */
  --spacing-96: 24rem;     /* 384px */

  /* Border Radius System */
  --radius-none: 0px;
  --radius-sm: 0.125rem;   /* 2px */
  --radius-default: 0.375rem; /* 6px */
  --radius-md: 0.5rem;     /* 8px */
  --radius-lg: 0.75rem;    /* 12px */
  --radius-xl: 1rem;       /* 16px */
  --radius-2xl: 1.5rem;    /* 24px */
  --radius-3xl: 2rem;      /* 32px */
  --radius-full: 9999px;

  /* Shadow System */
  --shadow-none: 0 0 0 0 rgba(0, 0, 0, 0);
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-default: 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);
  --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);

  /* Animation System */
  --transition-fast: 75ms;
  --transition-normal: 100ms;
  --transition-slow: 200ms;
  --transition-slower: 300ms;
  --transition-slowest: 500ms;

  /* Z-Index System */
  --z-0: 0;
  --z-10: 10;
  --z-20: 20;
  --z-30: 30;
  --z-40: 40;
  --z-50: 50;
  --z-auto: auto;

  /* Opacity System */
  --opacity-0: 0;
  --opacity-25: 0.25;
  --opacity-50: 0.5;
  --opacity-75: 0.75;
  --opacity-80: 0.8;
  --opacity-100: 1;

  /* Mobile-First Breakpoints - Standardized */
  --breakpoint-xs: 0px;
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
  --breakpoint-2xl: 1536px;
  --breakpoint-3xl: 1920px;

  /* Container Max Widths */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1280px;
  --container-2xl: 1536px;
  --container-3xl: 1920px;
}

/* Dark mode variables */
@media (prefers-color-scheme: dark) {
  :root {
    /* Color System - Primary (Burgundy) - Dark Mode */
    --color-primary-50: #6B0021;
    --color-primary-100: #910029;
    --color-primary-200: #CC4444;
    --color-primary-300: #E65555;
    --color-primary-400: #FF6666;
    --color-primary-500: #FF8080;
    --color-primary-600: #FF9999;
    --color-primary-700: #FFB3B3;
    --color-primary-800: #FFCCCC;
    --color-primary-900: #FFE4E4;
    --color-primary-950: #FFF5F5;

    /* Color System - Secondary (Dark Gray) - Dark Mode */
    --color-secondary-50: #1A1E22;
    --color-secondary-100: #39404B;
    --color-secondary-200: #212529;
    --color-secondary-300: #343A40;
    --color-secondary-400: #495057;
    --color-secondary-500: #6C757D;
    --color-secondary-600: #ADB5BD;
    --color-secondary-700: #CED4DA;
    --color-secondary-800: #DEE2E6;
    --color-secondary-900: #E9ECEF;
    --color-secondary-950: #F8F9FA;

    /* Color System - Accent (Light Blue-Gray) - Dark Mode */
    --color-accent-50: #020617;
    --color-accent-100: #0F172A;
    --color-accent-200: #1E293B;
    --color-accent-300: #334155;
    --color-accent-400: #475569;
    --color-accent-500: #64748B;
    --color-accent-600: #94A3B8;
    --color-accent-700: #CBD5E1;
    --color-accent-800: #E2E8F0;
    --color-accent-900: #F1F5F9;
    --color-accent-950: #F8FAFC;
  }
}