fix(css-variables): add root selector without classname

Need to add the `:root` in addition to `:root.classname` for some use cases, when we do not need to add the class in html tag for sites that does not have multiple themes

Author: iManu

utils/scripts/create-css-variables.tsx

@@ -69,7 +69,8 @@ export const generateThemeCss = ({
   uvTheme: UvThemeType
   filename: string
 }) =>
-  `:root.${filename}-theme {\n${
+  `:root,\n
+    :root.${filename}-theme {\n${
     createCssVariables('color', uvTheme.colors) +
     createCssVariables('radius', uvTheme.radii) +
     createCssVariables('shadow', uvTheme.shadows) +