Certificate Chain Action Required
If npm reports UNABLE_TO_VERIFY_LEAF_SIGNATURE and no .pem file is available, request the corporate CA bundle from the infrastructure team and ask the ProGet owners to publish the complete TLS certificate chain on the server. Fixing the server chain is the preferred long-term solution.
As a temporary local unblock only, run the install command with TLS verification disabled for that single process. Do not commit this setting, do not save it in a project .npmrc, and do not make it a global developer-machine default.
npm_config_strict_ssl=false npm install @seventh-ui/css