When you add a banner block to your page on Teachable, it might end up taking up the majority of your page. On some devices, it can be far too big.
That's because the styling code for the block defaults to trying to fill 70-90% of the height of your screen. So the bigger your device, the more overwhelming the banner block can be.
If you want to make it smaller, you need to add a little bit of styling code (called CSS) to your school.