Can't get tailwindcss grid to work in a Rails 7 project generated with --css tailwind flag

So I generated a brand new Rails 7 project with Tailwindcss and Postgres

rails new project -d postgresql --css tailwind

then I scaffolded a task model, which generated great looking css. Then I ventured to adapt the index page a bit, as the scaffold html/css drew it out vertically. I'm striving for a more horizontal layout, where individual tasks would form individual rows.

According to tailwind documentation I could use a grid for each task. As I have three attributes in a task I wanted to use a three column grid.

So I added grid gap-4 grid-cols-3 to my _task.html.haml

.grid.gap-4.grid-cols-3{:id => "#{dom_id task}"}
  .my-5
    %strong.block.font-medium.mb-1 Description:
    = task.description
  .my-5
    %strong.block.font-medium.mb-1 Notes:
    = task.notes
  .my-5
    %strong.block.font-medium.mb-1 Deadline:
    = task.deadline
  - if action_name != "show"
    = link_to "Show this task", task, class: "rounded-lg py-3 px-5 bg-gray-100 inline-block font-medium"
    = link_to 'Edit this task', edit_task_path(task), class: "rounded-lg py-3 ml-2 px-5 bg-gray-100 inline-block font-medium"
    %hr.mt-6

But it continues to render the attributes below each other.

After playing around with it and trying to figure out why it doesn't pick up the style I replicated the html/css in codepen.io.

<main class="container mx-auto mt-28 px-5 flex">
  <div class="w-full">
    <div class="flex justify-between items-center">
      <h1 class="font-bold text-4xl">Tasks</h1>
      <a class="rounded-lg py-3 px-5 bg-blue-600 text-white block font-medium" href="/tasks/new">New task</a>
    </div>
    <div class="min-w-full">
      <div class="grid gap-4 grid-cols-3" id="Task_1">
        <div class="my-5">
          <strong class="block font-medium.mb-1">Description:</strong>
          complete page 2 in math exercise book
        </div>
        <div class="my-5">
          <strong class="block font-medium.mb-1">Notes:</strong>
          try also the advanced exercises, but don't spend more than 10 minutes on them
        </div>
        <div class="my-5">
          <strong class="block font-medium.mb-1">Deadline:</strong>
          My Deadline
        </div>
      </div>  
      <div class="grid gap-4 grid-cols-3" id="Task_2">
        <div class="my-5">
          <strong class="block font-medium.mb-1">Description:</strong>
          Description
        </div>
        <div class="my-5">
          <strong class="block font-medium.mb-1">Notes:</strong>
          Some flippin' notes
        </div>
        <div class="my-5">
          <strong class="block font-medium.mb-1">Deadline:</strong>
          My Deadline
        </div>
      </div>  
    </div>
  </div>
</main>

There it rendered perfectly, just as I had intended.

What am I missing? Any help appreciated.