:root {
  /* Colors - Light Mode (Default) */
  --bg-primary: #F8FAFC;
  --bg-secondary: #F1F5F9;
  
  --surface: #FFFFFF;
  --surface-hover: #F8FAFC;
  --surface-active: #F1F5F9;

  --text-primary: #111827;
  --text-secondary: #475569;
  --text-muted: #5B677A;
  --text-disabled: #94A3B8;

  --border-subtle: #E2E8F0;
  --border-default: #CBD5E1;
  --border-strong: #7C879A;
  --border-focus: #3155D9;

  --accent-solid: #3155D9;
  --accent-hover: #2748C7;
  --accent-active: #203CA8;
  --accent-surface: #EEF2FF;
  --accent-text: #2748C7;
  --accent-contrast: #FFFFFF;
  
  --focus-ring: #3155D9;

  --success: #047857;
  --warning: #92400E;
  --danger: #B91C1C;
  --info: #1D4ED8;

  /* Typography */
  --font-family-base: 'Creato Display', Arial, sans-serif;
  --font-family-mono: monospace;
  
  --text-xs: 0.75rem;     /* 12px */
  --text-sm: 0.875rem;    /* 14px */
  --text-base: 1rem;      /* 16px */
  --text-lg: 1.125rem;    /* 18px */
  --text-xl: 1.25rem;     /* 20px */
  
  --heading-sm: clamp(1.25rem, 1.1rem + 0.5vw, 1.5rem);
  --heading-md: clamp(1.5rem, 1.2rem + 1vw, 2rem);
  --heading-lg: clamp(2rem, 1.5rem + 2vw, 3rem);
  --heading-xl: clamp(2.75rem, 1.8rem + 4vw, 5rem);

  /* Spacing */
  --space-1: 0.25rem; /* 4px */
  --space-2: 0.5rem;  /* 8px */
  --space-3: 0.75rem; /* 12px */
  --space-4: 1rem;    /* 16px */
  --space-5: 1.5rem;  /* 24px */
  --space-6: 2rem;    /* 32px */
  --space-7: 2.5rem;  /* 40px */
  --space-8: 3rem;    /* 48px */
  --space-9: 4rem;    /* 64px */
  --space-10: 5rem;   /* 80px */
  --space-11: 6rem;   /* 96px */
  --space-12: 7.5rem; /* 120px */
  --space-13: 10rem;  /* 160px */

  /* Radius */
  --radius-xs: 0.25rem;
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* Layout */
  --content-readable: 70ch;
  --content-main: 1280px;
  --page-gutter: clamp(1rem, 0.5rem + 2vw, 3rem);
  --section-space: clamp(4rem, 3rem + 5vw, 7.5rem);

  /* Motion */
  --duration-fast: 120ms;
  --duration-default: 180ms;
  --duration-slow: 260ms;
  --ease-standard: cubic-bezier(.2, .8, .2, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    /* Colors - Dark Mode */
    --bg-primary: #0D1117;
    --bg-secondary: #11161E;
    
    --surface: #151A22;
    --surface-hover: #1B2230;
    --surface-active: #222B3A;

    --text-primary: #F1F5F9;
    --text-secondary: #CBD5E1;
    --text-muted: #94A3B8;
    --text-disabled: #64748B;

    --border-subtle: #2A3441;
    --border-default: #3B4758;
    --border-strong: #64748B;
    --border-focus: #8EA2FF;

    --accent-solid: #3155D9;
    --accent-hover: #425FE0;
    --accent-active: #2748C7;
    --accent-surface: #18224A;
    --accent-text: #8EA2FF;
    --accent-contrast: #FFFFFF;
    
    --focus-ring: #8EA2FF;

    --success: #34D399;
    --warning: #FBBF24;
    --danger: #F87171;
    --info: #8EA2FF;
  }
}