The theme Responsive 1 is available in version 0.1.2. Reversed the logic of the CSS-rules for tables. Made several adjustments and added awful colours to a few elements for testing purposes.
The theme in this forum installation – it is not it's default theme! – is in the current state and reflects the version 0.1.2. You can test it with an active user account. Therefore you have to select it in your personal settings. You can find the compatibility list for browsers in the announcement of version 0.1.1.
Please report issues and opinions here or on Github.