您可以只組成 3 列，并將這些卡片堆放在每列上，而不是將每張卡片放在自己的列上：

<div class="row">

    <div class="col-12 col-md-4">

        <div class="card">#1</div>

        <div class="card">#4</div>

    </div>

    <div class="col-12 col-md-4">

        <div class="card">#2</div>

        <div class="card">#5</div>

    </div>

    <div class="col-12 col-md-4">

        <div class="card">#3</div>

    </div>

</div>

演示： https://jsfiddle.net/davidliang2008/w3t2qvzs/4/

您需要創建 3 列并將線條放入其中

這里的例子：https ://jsfiddle.net/ishnechmad/b94a8xnp/2/

<div class="container">

<div class="row">

<div class="col-12 col-md-4">

    <div class="row">

        <div id="accordion-1" class="col">

            <div class="card-header" id="heading-1">

                <h5 class="mb-0">

                    <button class="btn btn-link" data-toggle="collapse" data-target="#collapse-1" aria-expanded="true" aria-controls="collapse-1">

                                Collapsible #1

                    </button>

                </h5>

            </div>

            <div id="collapse-1" class="collapse" aria-labelledby="heading-1" data-parent="#accordion-1">

                <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>

    <div class="row">

        <div id="accordion-2" class="col">

                    <div class="card-header" id="heading-2">

                        <h5 class="mb-0">

                            <button class="btn btn-link" data-toggle="collapse" data-target="#collapse-2" aria-expanded="true" aria-controls="collapse-2">

                                Collapsible #2

                            </button>

                        </h5>

                    </div>

                    <div id="collapse-2" class="collapse" aria-labelledby="heading-2" data-parent="#accordion-2">

                        <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>

</div>

<div class="card col-12 col-md-4">

    <div class="row">

        <div id="accordion-3" class="col">

                    <div class="card-header" id="heading-3">

                        <h5 class="mb-0">

                            <button class="btn btn-link" data-toggle="collapse" data-target="#collapse-3" aria-expanded="true" aria-controls="collapse-3">

                                Collapsible #3

                            </button>

                        </h5>

                    </div>

                    <div id="collapse-3" class="collapse" aria-labelledby="heading-3" data-parent="#accordion-3">

                        <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>

    <div class="row">

        <div id="accordion-4" class="col">

                    <div class="card-header" id="heading-4">

                        <h5 class="mb-0">

                            <button class="btn btn-link" data-toggle="collapse" data-target="#collapse-4" aria-expanded="true" aria-controls="collapse-4">

                                Collapsible #4

                            </button>

                        </h5>

                    </div>

                    <div id="collapse-4" class="collapse" aria-labelledby="heading-4" data-parent="#accordion-4">

                        <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>

</div>

<div class="card col-12 col-md-4">

    <div class="row">

        <div id="accordion-5" class="col">

                    <div class="card-header" id="heading-5">

                        <h5 class="mb-0">

                            <button class="btn btn-link" data-toggle="collapse" data-target="#collapse-5" aria-expanded="true" aria-controls="collapse-5">

                                Collapsible #5

                            </button>

                        </h5>

                    </div>

                    <div id="collapse-5" class="collapse" aria-labelledby="heading-5" data-parent="#accordion-5">

                        <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>

    <div class="row">

    </div>

</div>

</div>

將布局元素與內容元素結合起來并不是一個好主意。將它們分開就可以了：

<div class="col-12 col-md-4">
  <div class="card">

演示小提琴