feat(prefers-color-scheme): add

Author: refirst11

src/core/index.ts

@@ -1,3 +1,4 @@
 export * from './breakpoint';
+export * from './prefers-color-scheme';
 import Style from './style';
 export default Style;

src/core/prefers-color-scheme.ts

@@ -0,0 +1,2 @@
+export const dark = '@media (prefers-color-scheme: dark)';
+export const light = '@media (prefers-color-scheme: light)';