I'd want to use Bootstrap to update the appearance of my forms.
Here's how my form's current view looks (it's quite basic...)
<div class="field">
    <%= form.label :first_name %>
    <%= form.text_field :first_name %>
  </div>
  <div class="field">
    <%= form.label :last_name %>
    <%= form.text_field :last_name %>
  </div>
  <div class="field">
    <%= form.label :age %>
    <%= form.number_field :age %>
  </div>
  <div class="field">
    <%= form.label :email %>
    <%= form.text_field :email %>
  </div>
  <div class="actions">
    <%= form.submit %>
  </div> 
<form>
  <div class="mb-3">
    <label for="exampleInputEmail1" class="form-label">Email address</label>
    <input type="email" class="form-control" id="exampleInputEmail1" aria-describedby="emailHelp">
    <div id="emailHelp" class="form-text">We'll never share your email with anyone else.</div>
  </div>
  <div class="mb-3">
    <label for="exampleInputPassword1" class="form-label">Password</label>
    <input type="password" class="form-control" id="exampleInputPassword1">
  </div>
  
  <button type="submit" class="btn btn-primary">Submit</button>
</form>
I'm not sure how to combine the ruby code and the HTML.