diff --git a/src/util/lang.ts b/src/util/lang.ts
index 5610168..5e39aa2 100644
--- a/src/util/lang.ts
+++ b/src/util/lang.ts
@@ -1,3 +1 @@
-export function classNames(...classes: (string | undefined | null | false)[]): string {
-  return classes.filter(Boolean).join(" ");
-}
+export { classNames } from "@quartz-community/utils/lang";
diff --git a/src/util/path.ts b/src/util/path.ts
index e442be5..7c04991 100644
--- a/src/util/path.ts
+++ b/src/util/path.ts
@@ -1,60 +1,11 @@
-export type FullSlug = string & { __brand: "FullSlug" };
-export type SimpleSlug = string & { __brand: "SimpleSlug" };
-export type RelativeURL = string & { __brand: "relative" };
-
-export function joinSegments(...args: string[]): string {
-  if (args.length === 0) return "";
-  let joined = args
-    .filter((segment) => segment !== "" && segment !== "/")
-    .map((segment) => stripSlashes(segment))
-    .join("/");
-  const first = args[0];
-  const last = args[args.length - 1];
-  if (first?.startsWith("/")) joined = "/" + joined;
-  if (last?.endsWith("/")) joined = joined + "/";
-  return joined;
-}
-
-export function stripSlashes(s: string, onlyStripPrefix?: boolean): string {
-  if (s.startsWith("/")) s = s.substring(1);
-  if (!onlyStripPrefix && s.endsWith("/")) s = s.slice(0, -1);
-  return s;
-}
-
-export function simplifySlug(fp: FullSlug): SimpleSlug {
-  const res = stripSlashes(trimSuffix(fp, "index"), true);
-  return (res.length === 0 ? "/" : res) as SimpleSlug;
-}
-
-export function trimSuffix(s: string, suffix: string): string {
-  if (endsWith(s, suffix)) s = s.slice(0, -suffix.length);
-  return s;
-}
-
-export function endsWith(s: string, suffix: string): boolean {
-  return s === suffix || s.endsWith("/" + suffix);
-}
-
-export function pathToRoot(slug: FullSlug): RelativeURL {
-  let rootPath = slug
-    .split("/")
-    .filter((x) => x !== "")
-    .slice(0, -1)
-    .map((_) => "..")
-    .join("/");
-  if (rootPath.length === 0) rootPath = ".";
-  return rootPath as RelativeURL;
-}
-
-export function resolveRelative(current: FullSlug, target: FullSlug | SimpleSlug): RelativeURL {
-  return joinSegments(pathToRoot(current), simplifySlug(target as FullSlug)) as RelativeURL;
-}
-
-export function isFolderPath(fplike: string): boolean {
-  return (
-    fplike.endsWith("/") ||
-    endsWith(fplike, "index") ||
-    endsWith(fplike, "index.md") ||
-    endsWith(fplike, "index.html")
-  );
-}
+export type { FullSlug, SimpleSlug, RelativeURL } from "@quartz-community/utils/path";
+export {
+  joinSegments,
+  stripSlashes,
+  simplifySlug,
+  trimSuffix,
+  endsWith,
+  pathToRoot,
+  resolveRelative,
+  isFolderPath,
+} from "@quartz-community/utils/path";