--- lib/font.ml	2023-03-21 18:21:51.000000000 +0800
+++ lib/font.ml	2025-10-18 14:53:28.000000000 +0800
@@ -72,11 +72,25 @@
 let atts_of_desc d = (d.underline, d.strikethrough, d.kerning, d.outline)
 
 let font_exts = ref [".ttf"]
-let font_dirs = ref
-  [ Filename.current_dir_name, false ;
-    "/usr/share/fonts/truetype", true ;
+
+let candidate_font_dirs =
+  [
+    Filename.current_dir_name, false ;
+    "@PREFIX@/share/fonts/truetype", true ;
+    "/opt/local/share/fonts", true ;            (* MacPorts *)
+    "/Library/Fonts", false ;                   (* macOS user-visible fonts *)
+    "/System/Library/Fonts", false ;            (* macOS system fonts *)
   ]
 
+let dir_exists d =
+  try
+    match (Unix.stat d).Unix.st_kind with
+    | Unix.S_DIR -> true
+    | _ -> false
+  with _ -> false
+
+let font_dirs = ref (List.filter (fun (d,_) -> dir_exists d) candidate_font_dirs)
+
 let fonts = ref SMap.empty
 
 let add_font ?(close=false) size file fn =
@@ -167,31 +181,37 @@
   let mutex = Lwt_mutex.create () in
   let rec iter size recur dir =
     Log.debug (fun m -> m "Loading fonts from directory %s" dir);
-    let stream = Lwt_unix.files_of_directory dir in
-    let%lwt l = Lwt_stream.to_list stream in
-    Lwt_list.iter_p
-      (fun e ->
-         if e = Filename.parent_dir_name ||
-           e = Filename.current_dir_name
-         then
-           Lwt.return_unit
-         else
-           (
-            let e = Filename.concat dir e in
-            match%lwt Lwt_unix.stat e with
-            | exception _ -> Lwt.return_unit
-            | { Unix.st_kind = S_REG } ->
-                Lwt_mutex.with_lock mutex
-                  (fun () -> Lwt.return(may_load_font size e))
-            | { st_kind = S_DIR } ->
-                if recur then
-                  iter size recur e
-                else
-                  Lwt.return_unit
-            | _ -> Lwt.return_unit
-           )
-      )
-      l
+    (* Guard directory existence again just in case the dir disappeared *)
+    match%lwt
+      (try Lwt.return (dir_exists dir) with _ -> Lwt.return_false)
+    with
+    | false -> Lwt.return_unit
+    | true ->
+      let stream = Lwt_unix.files_of_directory dir in
+      let%lwt l = Lwt_stream.to_list stream in
+      Lwt_list.iter_p
+        (fun e ->
+           if e = Filename.parent_dir_name ||
+             e = Filename.current_dir_name
+           then
+             Lwt.return_unit
+           else
+             (
+              let e = Filename.concat dir e in
+              match%lwt Lwt_unix.stat e with
+              | exception _ -> Lwt.return_unit
+              | { Unix.st_kind = S_REG } ->
+                  Lwt_mutex.with_lock mutex
+                    (fun () -> Lwt.return(may_load_font size e))
+              | { st_kind = S_DIR } ->
+                  if recur then
+                    iter size recur e
+                  else
+                    Lwt.return_unit
+              | _ -> Lwt.return_unit
+             )
+        )
+        l
   in
   iter