I fixed all the layout issues by rewriting the css but the slideshow still doesn't work.
The version that came with the j4 install is 1.1.11
the time stamp on those files is 11/29/2022
I compared the files and they aren't the same as used on your j4 demo.

There isn't an updated version listed in your extension downloads.

My team and I fixed all the issues, but had to swap the slideshow. So no need for anything on this site but I do have two or more three websites using Colette so please let me know when the J4 template is updated.
Thanks much!

Hi Mike

Thank you for bringing this error to our attention. This issue should be now resolved in the latest download of the template.

Ciaran

Excellent, thank you so much! I'll use the updated version on my next upgrade.
Love your templates!

The new version still isn't correct.

In the template custom css area I had to add:
@media (max-width: 767px){
#content_remainder {width: 100% !important;}
#main{display: block !important;}
.sidecol_a, .sidecol_b, .items-row .item, .showcase-1, .top-1, .top-2, .top-3, .contenttop, .contentbottom, .bottom-1, .bottom-2, .bottom-3, .base-1, .base-2 {
width: 100% !important;}
}

That worked to get the sidecol to wrap. That put it on the top of the main article area, which is not ideal but in this case it works for this site.

Also, you might want to include a note to your users that updating from J3 to J4 will delete out the J51_LayerSlideshow module and install the new blank one. So all the settings will be lost. Fortunately, I duplicated this site and therefore could jump into the J3 version and copy the slideshow data into the J4 version.

That was done on this site: https://forcebuilderscustomhomes.com