The selected trigger needs both .active and aria-selected="true".
<div class="tabs">
<div class="tabs-list" role="tablist">
<button type="button" class="tabs-trigger active" role="tab" aria-selected="true">Account</button>
<button type="button" class="tabs-trigger" role="tab" aria-selected="false">Security</button>
<button type="button" class="tabs-trigger" role="tab" aria-selected="false">API keys</button>
</div>
</div>
Add .tabs-underline to the container.
<div class="tabs tabs-underline">
<div class="tabs-list" role="tablist">
<button type="button" class="tabs-trigger active" role="tab" aria-selected="true">Overview</button>
<button type="button" class="tabs-trigger" role="tab" aria-selected="false">Usage</button>
</div>
</div>