Hi @chrijo_nrw,
You should be able to control the width/height of the header and logo with the 'Custom CSS' setting within the Instant Apps configuration window (Theme & Layout > Theme > Custom CSS).
The properties that you use will be based on the logo scale that was set.
Example:
instant-apps-header {
--instant-apps-header-logo-height--logo-scale--s: 80px;
--instant-apps-header-logo-width--logo-scale--s: 80px;
--instant-apps-header-height--logo-scale--s: 100px;
}
There is documentation of CSS properties for the instant-apps-components throughout the app (header, social share, etc.), but currently, not every part of the UI for each app.
Documentation on the header specifically can be found here:
https://github.com/Esri/instant-apps-components/tree/master/packages/instant-apps-components/src/com...
Hopefully this helps!
Best regards,
Ryan
