Modern CSS with Tailwind: Source code not working

Hi

I am having issues running the example code, tried on two machines (one I did install Ruby 3.0.0, but the this one is on one with an older Ruby version):

❯ bin/setup
== Installing dependencies ==
Warning: the running version of Bundler (2.1.4) is older than the version that created the lockfile (2.2.3). We suggest you to upgrade to the version that created the lockfile by running `gem install bundler:2.2.3`.
Your Ruby version is 2.6.3, but your Gemfile specified 3.0.0
Warning: the running version of Bundler (2.1.4) is older than the version that created the lockfile (2.2.3). We suggest you to upgrade to the version that created the lockfile by running `gem install bundler:2.2.3`.
Your Ruby version is 2.6.3, but your Gemfile specified 3.0.0

I think the main issue is the Gemfile specifiying Ruby 3, the Bundler is easy to solve.
Any help appreciated.

Yes, the Gemfile and the actual ruby version need to be consistent, for however you are specifying the Ruby file. We’ll make this easier for the final version