refactor component styles to use type-safe stitches tokens

https://stitches.dev/docs/typescript#stricter-experience

components/Blockquote/Blockquote.tsx

@@ -1,10 +1,10 @@
-import { styled } from "../../lib/styles/stitches.config";
+import { styled, theme } from "../../lib/styles/stitches.config";
 
 const Blockquote = styled("blockquote", {
   marginLeft: 0,
   paddingLeft: "1.25em",
-  borderLeft: "0.25em solid $link",
-  color: "$mediumDark",
+  borderLeft: `0.25em solid ${theme.colors.link}`,
+  color: theme.colors.mediumDark,
 });
 
 export default Blockquote;