In this example, the media query breakpoint is set 768px.
Resize window below 768px and controls will be an accordion.
Resize to 768px or above and they will appear as regular tabs.
<div class="tabs">
<h2>[...]</h2>
<div>[...]</div>
<h2>[...]</h2>
<div>[...]</div>
</div>
The headings can be any level, from h1 to h6. Note that the first (leftmost) tab panel will be open by default in 'tab view', while all panels will be closed in 'accordion view' (ie. below the specified breakpoint).
If you want a specific tab other than the first to be open by default then add the class 'responsive-tabs__panel--active' onto the panel, eg:
<div class="tabs">
<h2>[...]</h2>
<div>[...]</div>
<h2>[...]</h2>
<div class="responsive-tabs__panel--active">[...]</div>
</div>
responsiveTabs.js is available
Responsive-Tabs