Is your feature request related to a problem? Please describe.
It's frustrating to have any DOM nodes that don't allow styling, especially when they're provided by Theme UI.

Describe the solution you'd like
To be consistent with #1350, let's support sx on the BaseStyles component.

Additional context
https://github.com/system-ui/theme-ui/blob/develop/packages/theme-ui/src/i

Recently @devrnt opened up a PR to improve the setup with a theme(#189) and I realised that it'll be awesome to have that section expanded for each case.

There is an issue when adding new languages that I believe is related to react suspense. See i18next/react-i18next#977

Error:

Steps to reproduce:

1. Add a new language to Locize.
2. Make su

Animations can easily be reversed for cleanup using state to set the value of a reverse prop and is already implemented but it is not stated in documentation even though it works.

Example:

const [shown, setShown] = useState(false)
const yeetMenu = () => {
    setShown(!shown)
}
<Slide
      duration={500}
      triggerOnce={true}
      direction="right"
      reverse={shown}

https://github.com/ocsigen/tyxml