The theme Responsive 1 is available in version 0.1.3. Made a few adjustments and introduced the first 21 scalable icons in the SVG-format. As stated before the icons are also available from a separate repository.
The theme in this forum installation – it is not it's default theme! – is in the current state and reflects the version 0.1.3. 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.