Wayfinder works great with css dropdown menus. No need to use a static menu with Wayfinder at all. Susan's link will help, but basically all you need to do is build your css for the menu, and tell Wayfinder to use the id's and classes.
Something like this:
Wrap Wayfinder with your nav id or class:
<nav id="main_nav">[[Wayfinder? &startId=`0` &level=`0` &rowTpl=`rowTpl` &innerTpl=`innerTpl` &hideSubMenu=`0`]]</nav>
Standard Wayfinder rowTpl chunk:
<!-- rowTpl -->
<li[[+wf.id]] class="[[+wf.classnames]]">
<a href="[[+wf.link]]" title="[[+wf.title]]" [[+wf.attributes]]>[[+wf.linktext]]</a>
[[+wf.wrapper]]
</li>
Set your dropdown class in this innerTpl chunk:
<!-- innerTpl -->
<ul class="sublist [[+wf.classnames]]">
[[+wf.wrapper]]
</ul>