feat(docs): add docs and restructure

web/src/lib/remToPx.ts

@@ -0,0 +1,8 @@
+export function remToPx(remValue: number) {
+  let rootFontSize =
+    typeof window === 'undefined'
+      ? 16
+      : parseFloat(window.getComputedStyle(document.documentElement).fontSize)
+
+  return remValue * rootFontSize
+}