css 高度自动过渡三种方法（max-height、transform: scaleY()、grid-template-rows: 0fr）
方法一：使用max-height
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<div class="dropdown-toggle">hover me</div>
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<ul>
<li>Lorem, ipsum dolor.</li>
<li>Aut, ab facere.</li>
<li>Sint, assumenda reprehenderit!</li>
<li>Facilis, ipsa dolore!</li>
<li>Quae, nam provident!</li>
<li>Laborum, neque eligendi!</li>
<li>Ad, quas quo.</li>
<li>Vitae, facilis similique.</li>
</ul>
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