Update import to get type check passing

Author: lfarrell

docs/components/Splash/Element.tsx

@@ -1,14 +1,14 @@
 import React, { ReactElement } from "react";
 
-import { CSS } from "@stitches/react/types/css-util";
+import { CSS } from "@stitches/react";
 import CallToAction from "../CallToAction";
 import { styled } from "src/styles/stitches.config";
 import { useRouter } from "next/router";
 
 interface SplashElemenProps {
   component?: ReactElement;
   children?: React.ReactNode;
-  css?: CSS;
+  css: CSS;
   href: string;
   text: string;
 }