To use a custom font, modify your configuration settings in .chainlit/config.toml.

config.toml
[UI]
# This should be a google font url
custom_font = "https://fonts.googleapis.com/css2?family=Inter:wght@400;500;700&display=swap"

Then, update your theme’s font family to use the custom font.

config.toml
[UI.theme]
    font_family = "Inter, sans-serif"

Once the configuration is updated, restart the application. Your custom font will now be used.