延伸链接（Stretched link）
通过 CSS “拉伸”嵌套链接，使任何 HTML 元素或 Bootstrap 组件可点击。
将 .stretched-link添加到链接中，使其包含块可通过::after伪元素单击。在大多数情况下，这意味着具有 position: relative;的元素包含与.stretched-link类的链接是可点击的。请注意，鉴于CSS ‘position’是如何工作的，.stretched-link不能与大多数表格元素混合。
默认情况下，卡片在 Bootstrap 中具有 position: relative，因此在这种情况下，您可以安全地将.stretched-link类添加到卡片中的链接中，而无需任何其他 HTML 更改。
对于拉伸链接，不建议使用多个链接和点击目标。但是，如果需要，某些position 和z-index 样式会有所帮助。
Card with stretched link
Some quick example text to build on the card title and make up the bulk of the card's content.
Go somewhere<div class="card" style="width: 18rem;">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card with stretched link</h5>
<p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
<a href="#" class="btn btn-primary stretched-link">Go somewhere</a>
</div>
</div>大多数自定义组件默认没有position: relative，因此我们需要在此处添加.position-relative，以防止链接延伸到父元素之外。
Custom component with stretched link
This is some placeholder content for the custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.
Go somewhere<div class="d-flex position-relative">
<img src="..." class="flex-shrink-0 me-3" alt="...">
<div>
<h5 class="mt-0">Custom component with stretched link</h5>
<p>This is some placeholder content for the custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.</p>
<a href="#" class="stretched-link">Go somewhere</a>
</div>
</div>Columns with stretched link
Another instance of placeholder content for this other custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.
Go somewhere<div class="row g-0 bg-body-secondary position-relative">
<div class="col-md-6 mb-md-0 p-md-4">
<img src="..." class="w-100" alt="...">
</div>
<div class="col-md-6 p-4 ps-md-0">
<h5 class="mt-0">Columns with stretched link</h5>
<p>Another instance of placeholder content for this other custom component. It is intended to mimic what some real-world content would look like, and we're using it here to give the component a bit of body and size.</p>
<a href="#" class="stretched-link">Go somewhere</a>
</div>
</div>识别包含块
如果拉伸链接似乎不起作用，则包含块可能是原因。以下 CSS 属性将使元素成为包含块：
static以外的position值none以外的transform或perspective值transform或perspective的will-change值none以外的filter值或filter的will-change值（仅适用于 Firefox）
Card with stretched links
Some quick example text to build on the card title and make up the bulk of the card's content.
Stretched link will not work here, because position: relative is added to the link
This stretched link will only be spread over the p-tag, because a transform is applied to it.
<div class="card" style="width: 18rem;">
<img src="..." class="card-img-top" alt="...">
<div class="card-body">
<h5 class="card-title">Card with stretched links</h5>
<p class="card-text">Some quick example text to build on the card title and make up the bulk of the card's content.</p>
<p class="card-text">
<a href="#" class="stretched-link text-danger" style="position: relative;">Stretched link will not work here, because <code>position: relative</code> is added to the link</a>
</p>
<p class="card-text bg-body-tertiary" style="transform: rotate(0);">
This <a href="#" class="text-warning stretched-link">stretched link</a> will only be spread over the <code>p</code>-tag, because a transform is applied to it.
</p>
</div>
</div>