diff --git a/Dockerfile.frontend b/Dockerfile.frontend
index 3e57107..9644afa 100644
--- a/Dockerfile.frontend
+++ b/Dockerfile.frontend
@@ -1,7 +1,8 @@
 # Stage 1: build
 # Use the native build platform so npm ci never runs under QEMU emulation.
 # The build output (static HTML/JS/CSS) is platform-independent.
-FROM --platform=$BUILDPLATFORM node:20-alpine AS builder
+# node:20-slim (Debian/glibc) avoids lightningcss musl binary resolution issues on Alpine.
+FROM --platform=$BUILDPLATFORM node:20-slim AS builder
 
 ARG VITE_STANDALONE=false
 ENV VITE_STANDALONE=$VITE_STANDALONE