Respect LuCI theme on component cards

tests/luci_updates_theme.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+set -eo pipefail
+
+ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+SOURCE_STYLES="$ROOT_DIR/fe-app-forkop/src/forkop/tabs/updates/styles.ts"
+BUNDLE="$ROOT_DIR/luci-app-forkop/htdocs/luci-static/resources/view/forkop/main.js"
+
+fail() {
+  printf 'FAIL: %s\n' "$1" >&2
+  exit 1
+}
+
+source_card_styles="$(sed -n '/^\.fkp_updates-page__component {$/,/^}$/p' "$SOURCE_STYLES")"
+bundle_card_styles="$(sed -n '/^\.fkp_updates-page__component {$/,/^}$/p' "$BUNDLE")"
+
+[[ -n "$source_card_styles" ]] ||
+  fail "component card styles must exist in the frontend source"
+[[ -n "$bundle_card_styles" ]] ||
+  fail "component card styles must exist in the LuCI bundle"
+
+if grep -Eq '^[[:space:]]*background(-color)?:' <<<"$source_card_styles"; then
+  fail "component cards must inherit the active LuCI theme background"
+fi
+if grep -Eq '^[[:space:]]*background(-color)?:' <<<"$bundle_card_styles"; then
+  fail "bundled component cards must inherit the active LuCI theme background"
+fi
+
+printf 'LuCI updates theme checks passed\n'