diff --git a/Makefile b/Makefile
index 01fd96bb..9fbb28c7 100644
--- a/Makefile
+++ b/Makefile
@@ -24,7 +24,7 @@ BLUE := \033[1;34m
 DOCKER_UID          = $(shell id -u)
 DOCKER_GID          = $(shell id -g)
 DOCKER_USER         = $(DOCKER_UID):$(DOCKER_GID)
-COMPOSE             = DOCKER_USER=$(DOCKER_USER) docker compose
+COMPOSE             = DOCKER_USER=$(DOCKER_USER) DOCKER_UID=$(DOCKER_UID) docker compose
 COMPOSE_EXEC        = $(COMPOSE) exec
 COMPOSE_EXEC_APP    = $(COMPOSE_EXEC) backend-dev
 COMPOSE_RUN         = $(COMPOSE) run --rm
diff --git a/compose.yaml b/compose.yaml
index c4b02a9b..9df33e2a 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -131,7 +131,11 @@ services:
       - /app/.venv
 
   frontend-dev:
-    user: "${DOCKER_USER:-1000}"
+    # Keep the host UID (file ownership on the bind-mounted sources) but force
+    # the GID to 1000, the `node` group that owns the image's group-writable
+    # node_modules. On macOS the host GID is 20 (staff), not 1000, so the
+    # default ${DOCKER_USER} would leave Vite unable to write node_modules/.vite
+    user: "${DOCKER_UID:-1000}:1000"
     build:
       context: src/frontend
       target: calendars-dev