Completely new to Raspberry Pi and still trying to work out the kinks…

I am wondering if someone could help me resize the module on the right side of the screen. This module is pulling images from Flickr (not through API, but actual image files) and recreating into a slideshow.

I would like to large the module to fill the empty space on the right and center of the screen. I’ve attempted with custom CSS, but no luck so I’ve restored the custom CSS file to blank again. Would anyone have any suggestions?

Module CSS file: