diff --git a/scripts/sync_styleguide_to_webapp_aktienberater.sh b/scripts/sync_styleguide_to_webapp_aktienberater.sh
index c77404e..d870326 100755
--- a/scripts/sync_styleguide_to_webapp_aktienberater.sh
+++ b/scripts/sync_styleguide_to_webapp_aktienberater.sh
@@ -68,7 +68,32 @@ PORTAL_STYLEGUIDE_DOCS_PATH="$PORTAL_REPO_PATH/$PORTAL_STYLEGUIDE_DOCS_REL"
 mkdir -p "$(dirname "$PORTAL_CSS_PATH")"
 mkdir -p "$PORTAL_STYLEGUIDE_DOCS_PATH"
 
-cp "$SOURCE_CSS" "$PORTAL_CSS_PATH"
+flatten_css() {
+  local source_file="$1"
+  local source_root="$2"
+  local output_file="$3"
+
+  : > "$output_file"
+  while IFS= read -r line; do
+    if [[ "$line" =~ ^[[:space:]]*@import[[:space:]]+\"([^\"]+)\"[[:space:]]*\;[[:space:]]*$ ]]; then
+      local import_path="${BASH_REMATCH[1]}"
+      local import_abs="$source_root/$import_path"
+      if [[ ! -f "$import_abs" ]]; then
+        echo "Imported CSS not found: $import_abs" >&2
+        exit 1
+      fi
+      cat "$import_abs" >> "$output_file"
+      printf "\n" >> "$output_file"
+    else
+      printf "%s\n" "$line" >> "$output_file"
+    fi
+  done < "$source_file"
+}
+
+TMP_UPSTREAM_CSS="$(mktemp)"
+trap 'rm -f "$TMP_UPSTREAM_CSS"' EXIT
+flatten_css "$SOURCE_CSS" "$STYLEGUIDE_REPO_ROOT" "$TMP_UPSTREAM_CSS"
+cp "$TMP_UPSTREAM_CSS" "$PORTAL_CSS_PATH"
 
 rsync -a --delete \
   --exclude ".git/" \