3rdparty.less inlines Ink's stylesheets with @import (inline), which copies their sourceMappingURL comments into the compiled bundles. collectstatic's post-processing then tries to resolve the referenced maps as lib/css/ink.css.map and lib/css/ink-auto.css.map, and fails the whole build because they were never collected. build-media.py now maps Ink's CSS source maps into lib/css/ through its STATICFILES_DIRS override, alongside the existing jquery-ui images entry, so post-processing can resolve and fingerprint them. This was a regression from the updated Ink build, which started shipping source maps next to its built stylesheets. Testing Done: Built static media.