Roboto Mono is inlined as a base64 data URI, one weight

The package builds with bare tsc and has no asset pipeline that could rewrite a .woff2 URL for a consumer's bundler, so the latin subset of Roboto Mono 400 (Apache-2.0) ships as a data: URI in src/theme/font.ts, roughly 16KB. @font-face is ignored inside a shadow root, so ensureFontFace() registers it against the document; importing themeStyles calls it, and without it the family falls back to the system mono stack.

One weight only — a second would roughly double those bytes — so hierarchy is expressed through tint and letter-spacing rather than a bolder face that would otherwise be synthesised.