Changing image height on mobile only using CSS

Site URL: https://miserytakeme.co.uk/coming-soon

Hi, 

I'm currently trying to work out how to make my image crop nicely on a mobile view, if I can reduce the height of the image on mobile so the image will sit nicely, that would be perfect. At the minute it zooms in and the image is obscured. I'll attach screenshots of the desktop and mobile views so you can see what I mean

If I can inject some custom CSS in the design tab that would be ideal. I'm pretty new to coding and don't really know what I'm doing so any help would be amazing! I've had a look around the forum and haven't found anything thats worked for me, but that is probably me misusing the coding

Also I have both the ID's for the block, the numbered one and the "yui" ID, not entirely sure what the difference is between them

Thank you!

Hi. It looks like you solved?