7.1 Slideshow Gallery Section Mobile Resize HELP

Site URL: https://grasshopper-trombone-m7l2.squarespace.com/

Hi there

I'm super new to custom CSS. I've been really struggling with the functionality of Squarespace 7.1 from a design perspective. As such i've reached a stumbling block. I have a full width slideshow gallery on my homepage. But when I look on the mobile view it is not resizing. Squarespace can offer no solution. Does anyone know how to automatically resize for mobile? 

I'm having a similar issue with a gallery of client logos. On mobile they are coming up as a single column. Is there anyway I can create three columns or something?

thanks in advance

Your site is private. Can you setup password & share url?