Iframe
When your application lives in an iframe inside the Suite, you have to build the layout inside your iframe. As there is no main navigation in your application, you have to use a special modifier on the element with the e-layout class called e-layout-without_navigation.
<div class="e-layout e-layout-without_navigation">
<header class="e-layout__header">
<h1 class="e-layout__title">Sample Application</h1>
</header>
<main class="e-layout__content">
<section class="e-layout__section">
<!-- Section content -->
</section>
</main>
</div>
The outer frame is already taken care in the Suite like this:
<div class="e-layout">
<iframe src="https://ui.static.emarsys.net" class="e-layout__iframe"></iframe>
</div>