feat(brand): emit --font-size-* and --z-* CSS custom properties

Mirror the existing TS token scales as CSS custom properties so the JS
tokens (typography.ts `fontSize`, tokens.ts `zIndex`) and the standalone
styles/variables.css agree exactly:

- --font-size-xs … --font-size-9xl  (mirrors typography.fontSize)
- --z-0 … --z-50 + --z-dropdown/sticky/overlay/modal/popover/tooltip/
  notification  (mirrors tokens.zIndex)

Lets every Hanzo surface consume one coherent font-size + z-index scale
via brand CSS vars without importing JS.

Co-authored-by: Hanzo Dev <[email protected]>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hanzo/brand",
-  "version": "1.4.1",
+  "version": "1.4.2",
   "description": "Official brand assets and design system for Hanzo AI",
   "main": "dist/index.js",
   "module": "dist/index.mjs",

styles/variables.css

@@ -136,6 +136,36 @@
   /* ===== Typography ===== */
   --font-sans: 'Geist Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
   --font-mono: 'Geist Mono', Monaco, monospace;
+
+  /* ===== Font Size scale (mirrors typography.ts `fontSize`) ===== */
+  --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 */
+
+  /* ===== Z-index ladder (mirrors tokens.ts `zIndex`) ===== */
+  --z-0: 0;
+  --z-10: 10;
+  --z-20: 20;
+  --z-30: 30;
+  --z-40: 40;
+  --z-50: 50;
+  --z-dropdown: 100;
+  --z-sticky: 200;
+  --z-overlay: 300;
+  --z-modal: 400;
+  --z-popover: 500;
+  --z-tooltip: 600;
+  --z-notification: 700;
 }
 
 /* Dark theme (default for Hanzo) */