diff --git a/infra/Dockerfile.server b/infra/Dockerfile.server
index 0d0f321..da31c42 100644
--- a/infra/Dockerfile.server
+++ b/infra/Dockerfile.server
@@ -1,22 +1,25 @@
 # ── Build stage ───────────────────────────────────────────────────────────────
-FROM rust:1.94-slim-bookworm AS builder
-
-WORKDIR /build
+FROM rust:1.84-slim-bookworm AS builder
 
 RUN apt-get update && apt-get install -y \
-    pkg-config libssl-dev \
+    pkg-config \
+    musl-tools \
     && rm -rf /var/lib/apt/lists/*
 
+RUN rustup target add aarch64-unknown-linux-musl
+
+WORKDIR /build
+
 # Cache dependencies separately from source.
 COPY Cargo.toml Cargo.lock* ./
 COPY server/Cargo.toml ./server/
 RUN mkdir -p server/src && echo 'fn main(){}' > server/src/main.rs
-RUN cargo build --release -p hiy-server 2>/dev/null || true
+RUN cargo build --release --target aarch64-unknown-linux-musl -p hiy-server 2>/dev/null || true
 RUN rm -f server/src/main.rs
 
 # Build actual source.
 COPY server/src ./server/src
-RUN touch server/src/main.rs && cargo build --release -p hiy-server
+RUN touch server/src/main.rs && cargo build --release --target aarch64-unknown-linux-musl -p hiy-server
 
 # ── Runtime stage ─────────────────────────────────────────────────────────────
 FROM debian:bookworm-slim
@@ -31,7 +34,7 @@ RUN apt-get update && apt-get install -y \
     docker.io \
     && rm -rf /var/lib/apt/lists/*
 
-COPY --from=builder /build/target/release/hiy-server /usr/local/bin/hiy-server
+COPY --from=builder /build/target/aarch64-unknown-linux-musl/release/hiy-server /usr/local/bin/hiy-server
 
 WORKDIR /app