如何在Bootstrap 4手风琴示例中折叠边框？

Question

I'd like to adapt the accordion example from https://getbootstrap.com/docs/4.0/components/collapse/#accordion-example . However, I've noticed that the borders in between the collapsible group items are wider than the ones at the top and bottom:

I think it would look nicer if the borders were all the same with, similar to using the borde-collapse property for tables. How might I achieve this?

Here is a snippet:

 <link href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet"/> <div id="accordion"> <div class="card"> <div class="card-header" id="headingOne"> <h5 class="mb-0"> <button class="btn btn-link" data-toggle="collapse" data-target="#collapseOne" aria-expanded="true" aria-controls="collapseOne"> Collapsible Group Item #1 </button> </h5> </div> <div id="collapseOne" class="collapse show" aria-labelledby="headingOne" data-parent="#accordion"> <div class="card-body"> Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS. </div> </div> </div> <div class="card"> <div class="card-header" id="headingTwo"> <h5 class="mb-0"> <button class="btn btn-link collapsed" data-toggle="collapse" data-target="#collapseTwo" aria-expanded="false" aria-controls="collapseTwo"> Collapsible Group Item #2 </button> </h5> </div> <div id="collapseTwo" class="collapse" aria-labelledby="headingTwo" data-parent="#accordion"> <div class="card-body"> Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS. </div> </div> </div> <div class="card"> <div class="card-header" id="headingThree"> <h5 class="mb-0"> <button class="btn btn-link collapsed" data-toggle="collapse" data-target="#collapseThree" aria-expanded="false" aria-controls="collapseThree"> Collapsible Group Item #3 </button> </h5> </div> <div id="collapseThree" class="collapse" aria-labelledby="headingThree" data-parent="#accordion"> <div class="card-body"> Anim pariatur cliche reprehenderit, enim eiusmod high life accusamus terry richardson ad squid. 3 wolf moon officia aute, non cupidatat skateboard dolor brunch. Food truck quinoa nesciunt laborum eiusmod. Brunch 3 wolf moon tempor, sunt aliqua put a bird on it squid single-origin coffee nulla assumenda shoreditch et. Nihil anim keffiyeh helvetica, craft beer labore wes anderson cred nesciunt sapiente ea proident. Ad vegan excepteur butcher vice lomo. Leggings occaecat craft beer farm-to-table, raw denim aesthetic synth nesciunt you probably haven't heard of them accusamus labore sustainable VHS. </div> </div> </div> </div> <script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script> <script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js" integrity="sha384-smHYKdLADwkXOn1EmN1qk/HfnUcbVRZyYmZ4qpPea6sjB/pTJ0euyQp0Mk8ck+5T" crossorigin="anonymous"></script> 

Answer 1

To get the same border on each of these tabs, you need to edit the .card class. Like this:

.card {

  position: relative;
  display: flex;
  flex-direction: column;
  min-width: 0;
  word-wrap: break-word;
  background-color: #FFF;
  border: 0px solid rgba(0,0,0,.125); /*EDIT this part*/
  border-radius: 0.25rem;

}

This will make the border look like this on each:

Answer 2

Use borde-bottom-0 for the cards to remove just border-bottom of them.

https://codepen.io/anon/pen/PaBpvv

---

Use border-0 for the cards to remove border top, right, bottom, and left.. To remove radius, use no-radius .

https://codepen.io/anon/pen/mKjmJg

Answer 3

I noticed that Bootstrap's source code contains the following SCSS:

.accordion {
  .card:not(:first-of-type):not(:last-of-type) {
    border-bottom: 0;
    border-radius: 0;
  }

  .card:not(:first-of-type) {
    .card-header:first-child {
      border-radius: 0;
    }
  }

  .card:first-of-type {
    border-bottom: 0;
    border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;
  }

  .card:last-of-type {
    border-top-left-radius: 0;
    border-top-right-radius: 0;
  }
}

So simply adding class="accordion" makes the 'inner' borders the same width as the 'outer' ones. This is illustrated in https://jsfiddle.net/8m2g9jsx/1/ . Strange that Bootstrap does not include the use of this class in its example in the documentation.