likeboxもといpage plugin facebook ウィジェットのレスポンシブ

	.fb_iframe_widget{ width:100%}

.fb_iframe_widget iframe{ width:100%}
<div class="fb-page" data-href="https://www.facebook.com/0568navi/" data-small-header="false" data-adapt-container-width="true" data-hide-cover="false" data-show-facepile="true" data-show-posts="true" data-width="500" ></div>

https://developers.facebook.com/docs/plugins/page-plugin