HI Matthias
In general, it's a CSS/HTML question. But let's say, I can share tip for Raw HTML addon:
<div class="iframe-container">
<iframe src="/CARS-LINK" frameborder="0"></iframe>
</div>
And inside Page Settings > Custom CSS add also those lines:
/* Parent container must have a defined height */
.iframe-container {
height: 100%; /* Full height of viewport or parent */
width: 100%; /* Optional: Full width of parent */
overflow: hidden; /* Prevent scrollbars if necessary */
}
/* The iframe itself */
iframe {
width: 100%; /* Full width */
height: 100%; /* Full height */
border: none; /* Optional: Removes the default border */
display: block; /* Removes inline spacing */
}