layout--uw-1-col.html.twig

{%
  set classes = [
  'layout',
  'layout--uw-1-col',
  settings.column_class,
]
%}

<section{{ attributes.addClass(classes) }}>
  <div {{ region_attributes.first.addClass('layout__region', 'layout__region--first') }}>
      {{ content.first }}
  </div>
</section>