Ajuda com hamburger-icon

Olá! Preciso de uma ajuda, por favor.

Eu criei um site pelo Mobirise. Fiz tudo certinho.

Mas esses dias eu fui até o wc3 validator para ver se estava tudo ok com o meu site.

Então quando verifiquei, deu esse seguinte erro:

Error: Element div not allowed as child of element button in this context. (Suppressing further errors from this subtree.)

From line 65, column 25; to line 65, column 52

	**<div class="hamburger-icon">**</div>

 Contexts in which element [div](http://www.w3.org/html/wg/drafts/html/master/single-page.html#the-div-element) may be used:

 Where [flow content](http://www.w3.org/html/wg/drafts/html/master/single-page.html#flow-content-2) is expected.

 As a child of a [dl](http://www.w3.org/html/wg/drafts/html/master/single-page.html#elementdef-dl) element.

 Content model for element [button](http://www.w3.org/html/wg/drafts/html/master/single-page.html#the-button-element):

 [Phrasing content](http://www.w3.org/html/wg/drafts/html/master/single-page.html#phrasing-content-2), but there must be no [interactive content](http://www.w3.org/html/wg/drafts/html/master/single-page.html#interactive-content-2) descendant.

	O que seria isso? Alguém pode me ajudar? Agradeço!