The CSS has all the definitions with selectors of type ">", allowing to add inside the accordions without fear of inheritance problems. We have added CSS3 animations, although they are not necessary. We have avoided using animations on min-height, due to known problems.
<div class="Accordion">
<ul>
<li>
<input type="checkbox" id="1">
<label for="1">One</label>
<div>
Content
</div>
</li>
<li>
<input type="checkbox" id="2">
<label for="2">Two</label>
<div>
Content
</div>
</li>
</ul>
</div>