Setup 🛠 Rails 8 App – Part 4: Tailwind CSS 🎨 into the action

Does Tailwind Take Time?

  • If you haven’t used Tailwind before, expect a slight learning curve (1-2 days) to get comfortable.
  • But once you grasp utility classes, styling becomes faster than Bootstrap.

Fastest Way to Set Up Tailwind in Rails 8

1. Install Tailwind

   rails new myapp --css=tailwind

Or, if you already have a Rails app:

   ✗ bundle add tailwindcss-rails
     Fetching gem metadata from https://rubygems.org/.........
     Resolving dependencies...
     Fetching gem metadata from https://rubygems.org/.........
     Resolving dependencies...
     Fetching tailwindcss-ruby 4.0.17 (arm64-darwin)
     Installing tailwindcss-ruby 4.0.17 (arm64-darwin)
     Fetching tailwindcss-rails 4.2.1
     Installing tailwindcss-rails 4.2.1
   
  ✗ rails tailwindcss:install
      apply  /Users/abhilash/.local/share/mise/installs/ruby/3.4.1/lib/ruby/gems/3.4.0/gems/tailwindcss-rails-4.2.1/lib/install/install_tailwindcss.rb
  Add Tailwindcss container element in application layout
      insert    app/views/layouts/application.html.erb
      insert    app/views/layouts/application.html.erb
  Build into app/assets/builds
      create    app/assets/builds
      create    app/assets/builds/.keep
      append    .gitignore
  Add default /Users/xxxxx/rails/design_studio/app/assets/tailwind/application.css
      create    app/assets/tailwind/application.css
  Add default Procfile.dev
      create    Procfile.dev
  Ensure foreman is installed
         run    gem install foreman from "."
         Fetching foreman-0.88.1.gem
         Successfully installed foreman-0.88.1

Refer: https://tailwindcss.com/docs/installation/framework-guides/ruby-on-rails

Note: You can see this create a Procfile.dev file and installs foreman gem.

The foreman gem in Rails is used to manage and run multiple processes in development using a Procfile. It is particularly useful when your Rails application depends on several background services that need to run simultaneously.

Why is foreman used?

  • It allows you to define and manage multiple services (like Rails server, Tailwind compiler, Sidekiq, etc.) in a single command.
  • Ensures that all necessary processes start together, making development easier.
  • Helps simulate production environments where multiple services need to run concurrently.

Who is using foreman? Rails or Tailwind CSS?

  • The foreman gem itself is not specific to Rails or Tailwind CSS—it is a general-purpose process manager.
  • In our case, both Rails and Tailwind CSS are using foreman.
    • Rails: You can use foreman to start Rails server, background jobs, and Webpack.
    • Tailwind CSS: Since Tailwind needs a process to watch and compile CSS files (using npx tailwindcss -i input.css -o output.css --watch), foreman helps keep this process running.

What is Procfile.dev in Tailwind CSS?

  • When you install Tailwind in Rails, a Procfile.dev is created to define the processes required for development.
  • Example Procfile.dev for Tailwind and Rails:
    web: bin/rails server -p 3000
    js: yarn build --watch
    css: bin/rails tailwindcss:watch
    • web: Starts the Rails server.
    • js: Watches and compiles JavaScript files (if using esbuild or webpack).
    • css: Watches and compiles Tailwind CSS files.

How to use foreman?

  • Run the following command to start all processes defined in Procfile.dev: bin/dev
    • This starts the Rails server, the Tailwind CSS watcher, and other necessary processes.

The foreman gem is used as a process manager to run multiple services in development. In our case, both Rails and Tailwind CSS are using it. It ensures that Tailwind’s CSS compilation process runs alongside the Rails server.

2. Use Tailwind Classes in Views

Example:

   <div class="container mx-auto p-4">
     <h1 class="text-blue-500 text-3xl font-bold">Welcome to My App</h1>
     <button class="bg-green-500 text-white px-4 py-2 rounded">Click Me</button>
   </div>

This keeps your CSS minimal, avoids custom stylesheets, and helps you learn Tailwind naturally while building your app.

Here’s a Tailwind CSS Cheat Sheet to help you get started quickly with your Rails 8 app.

📌 1. Layout & Spacing

<div class="container mx-auto p-4">
  <div class="m-4 p-4 bg-gray-200">Margin & Padding</div>
</div>
  • mx-auto → Center content horizontally
  • p-4 → Padding (4 * 4px = 16px)
  • m-4 → Margin (4 * 4px = 16px)

🎨 2. Colors

<div class="bg-blue-500 text-white p-4">Blue Background</div>
<div class="text-red-600">Red Text</div>
  • Colors: gray, red, blue, green, etc.
  • Shades: 100 - 900 (lighter → darker)

Refer: https://tailwindcss.com/docs/background-color

🔤 3. Typography

<p class="text-lg font-bold">Large Bold Text</p>
<p class="text-sm italic">Small Italic Text</p>
  • text-lg → Large text
  • text-sm → Small text
  • font-bold → Bold text
  • italic → Italic text

📏 4. Width & Height

<div class="w-1/2 h-32 bg-green-300">50% Width, 128px Height</div>
  • w-1/2 → 50% width
  • w-full → Full width
  • h-32 → 128px height

🔳 5. Flexbox & Grid

<div class="flex justify-center items-center h-screen">
  <div class="bg-blue-500 p-4 text-white">Centered Box</div>
</div>
  • flex → Enables flexbox
  • justify-center → Centers horizontally
  • items-center → Centers vertically

🔘 6. Buttons

<button class="bg-blue-500 hover:bg-blue-700 text-white font-bold py-2 px-4 rounded">
  Click Me
</button>
  • hover:bg-blue-700 → Darker blue on hover
  • rounded → Rounded corners

🔗 7. Borders & Shadows

<div class="border border-gray-400 shadow-lg p-4">Border & Shadow</div>
  • border → Default border
  • border-gray-400 → Gray border
  • shadow-lg → Large shadow

📲 8. Responsive Design

<div class="p-4 text-sm md:text-lg lg:text-xl">
  Text size changes on different screens!
</div>
  • sm: → Small screens (≥ 640px)
  • md: → Medium screens (≥ 768px)
  • lg: → Large screens (≥ 1024px)

✨ 9. Animations & Transitions

<button class="bg-green-500 transition duration-300 hover:bg-green-700">
  Smooth Transition
</button>
  • transition → Enables animations
  • duration-300 → 300ms transition speed
  • hover:bg-green-700 → Change color on hover

🚀 Quick Setup for Your Rails 8 App

  1. Install Tailwind
   rails new myapp --css=tailwind
  1. Use Tailwind Classes in Views
   <div class="text-center p-6 text-2xl text-blue-500">Hello Tailwind!</div>

🔥 Bonus: Try Tailwind Play for live previews!

Tailwind in design studio

Check our Rails 8 app for tailwind implementation: https://github.com/abhilashak/design_studio/blob/main/bin/dev

I have added Tailwind CSS to our design_studio app. You can check the commit here: https://github.com/abhilashak/design_studio/commit/07db459

Track our Github Issue for tailwind task: https://github.com/abhilashak/design_studio/issues/1

The above issue will be automatically closed if you follow our Git commit message principle, that is mentioned in the below post:

Git Workflow 🔀: Best Practices for Your Development Process

Finally add the Tailwind Plugin Tailwind CSS IntelliSense for VS Code to make development easy.

to be continued.. 🚀

Unknown's avatar

Author: Abhilash

Hi, I’m Abhilash! A seasoned web developer with 15 years of experience specializing in Ruby and Ruby on Rails. Since 2010, I’ve built scalable, robust web applications and worked with frameworks like Angular, Sinatra, Laravel, Node.js, Vue and React. Passionate about clean, maintainable code and continuous learning, I share insights, tutorials, and experiences here. Let’s explore the ever-evolving world of web development together!

One thought on “Setup 🛠 Rails 8 App – Part 4: Tailwind CSS 🎨 into the action”

  1. Pingback: Understanding Confusing 🧐 Ruby Concepts: Procfile, Rake, Rack, and More – The Rails Drop

Leave a comment