Hello, Thanks for reporting. This is fixed and pushed to GitHub. But do not update in live site unless I mark it as stable.
Yes its possible. Open includes\less\askbug.less and remove line 14 @import “responsive”;. Then go to wp-admin->appearance->customizer and simply change main color and save.
Hello Peter, Thanks for reaching us. I am well aware of this issue. I will add fix in upcoming release.