refactor: deduplicate CSS parser helpers and drop redundant base test

- Collapse extractRootBlock + extractDarkBlock into a single extractBlock
  helper; the two functions shared identical body logic (same regex, same
  return) and differed only in the string they received — now the call
  sites pass the appropriate slice inline.
- Remove the second test in base.test.ts ("covers all three form control
  selectors in one rule"): the first test's regex already asserts all
  three selectors appear together with font-size: 16px, so the individual
  /input/, /textarea/, /select/ matches added no coverage.

tests/base.test.ts

@@ -8,9 +8,4 @@ describe('base.css', () => {
     expect(css).toMatch(/input\s*,\s*textarea\s*,\s*select\s*\{[^}]*font-size\s*:\s*16px/);
   });
 
-  it('covers all three form control selectors in one rule', () => {
-    expect(css).toMatch(/input/);
-    expect(css).toMatch(/textarea/);
-    expect(css).toMatch(/select/);
-  });
 });

tests/tokens.test.ts

@@ -5,17 +5,11 @@ const css = readFileSync(new URL('../dist/tokens.css', import.meta.url), 'utf-8'
 
 // ---- CSS parser helpers ----
 
-function extractRootBlock(src: string): string {
+function extractBlock(src: string): string {
   const m = src.match(/:root\s*\{([^}]+)\}/);
   return m?.[1] ?? '';
 }
 
-function extractDarkBlock(src: string): string {
-  const afterMedia = src.split('@media (prefers-color-scheme: dark)')[1] ?? '';
-  const m = afterMedia.match(/:root\s*\{([^}]+)\}/);
-  return m?.[1] ?? '';
-}
-
 function parseProps(block: string): Map<string, string> {
   const map = new Map<string, string>();
   const re = /--([\w-]+)\s*:\s*([^;]+);/g;
@@ -63,8 +57,8 @@ function contrast(hex1: string, hex2: string): number {
 
 // ---- Fixtures ----
 
-const rootProps = parseProps(extractRootBlock(css));
-const darkProps = parseProps(extractDarkBlock(css));
+const rootProps = parseProps(extractBlock(css));
+const darkProps = parseProps(extractBlock(css.split('@media (prefers-color-scheme: dark)')[1] ?? ''));
 // Merged: dark overrides on top of light primitives so var() refs resolve correctly.
 const mergedDark = new Map([...rootProps, ...darkProps]);