@layer theme { /* Generic .dropdown-menu popup. Nothing in luci-base emits it — the split "Save & Apply" button is * a `.cbi-dropdown`, a different widget — so this is coverage vocabulary: stock * luci-theme-bootstrap styles it, so a third-party luci-app-* may emit it and expect a themed * result — theme/10-chrome.css claims the same class for the same reason. Not the theme's nav * menu, which is a plain nested