funky/_includes/header.html

<header class="header">

	<div class="container">

		{% if site.logo %}
		  <a class="logo" href="{{ site.url }}" title="{{ site.title }}">
		    <img class="image" src="{{ site.logo | replace: "300", "72" }}" alt="{{ site.title }}" srcset="{{ site.logo | replace: "300", "72" }}  72w, {{ site.logo | replace: "300", "144" }} 144w" width="72" height="72">
		  </a>
		{% endif %}

		<button class="button">Menu</button>

		<nav class="nav  nav--main">
		  {% if data.nav %}

		    {% for item in data.nav %}
		      <a class="item" href="{{ item.url }}" title="{{ item.name }}">{{ item.name }}</a>
		    {% endfor %}

		  {% else %}

		    {% for page in site.pages %}
					{% if page.title %}
		      	<a class="item" href="{{ page.url }}" title="{{ page.title }}">{{ page.title }}</a>
					{% endif %}
		    {% endfor %}

		  {% endif %}
		</nav>

	</div>

</header>