The UI and code fonts are each a native stack that covers every platform, so the app loads no web fonts. The sans drops ui-sans-serif, which only Safari reads, and "SF Pro Text", which system-ui already reaches, names Helvetica and Arial for Linux, where they map to lookalikes, and ends with the emoji fonts of each platform after sans-serif, Noto Color Emoji among them for Linux and Android. The mono gives SF Mono in Safari and on iOS through ui-monospace, Menlo in Chrome and Firefox on a Mac, which can't reach SF Mono, Cascadia Mono or Consolas on Windows, and Liberation Mono or DejaVu Sans Mono on Linux, and no longer names JetBrains Mono, which is only there when someone installed it.