I must have done something really stupid! Suddenly the Preview in Site Designer does not work. I can Preview in a browser but not in Site Designer. The links work when Previewed in both Edge and Chrome, but not in Site Designer. It is very frustrating as a quick preview is really helpful to see that things look like you expect them to do.

Links usually don't work in SD. You have to preview in a browser. So most likely you haven't done anything stupid

I just regularly feel stupid using SD. I am an old lady, after all!!
Thanks for making me feel less stupid.
I do seem to have made a mess of your Basic Cards:Foundation Component, though. I definitely does not look right!!

The built-in preview in SD can be used to see how something looks, but to test functionality you just have to use a real browser. It has always been like that.

Good luck,
from another old lady who has also felt stupid at some time

Oh, I didn't get that at first. What kind of trouble do you have with the basic card component? I need to call it a day now, but I'll take a look tomorrow if you are still having a mess with them.

When I insert the component into my site, I get the warning shown in the first picture and it displays as shown in the second picture

The first message says it all

Basically you have other containers with the same ID on that page which cannot happen.

So site designer gives the ID a name wth a number something like copy-1

You need re-apply styling link triggers etc to those elements.

In this case, there is no ID involved, it is a class name - or more class names. The first instance of it usually is left as is, and further instances of it/them get the '-1' appended. My guess is, that the class .card-divider has become card-divider-1 on the scilla and the tulip, so change it to card-divider-1 on the rose too. And do similar with the other instances of this.

The reason why this happens is to avoid creating havoc with page elements where you have already used the same class name, so the havoc happens when something new appears on the scene. I have reported this to the CC staff several times, but it seems that they haven't found a way to change ALL the bits of a new element, instead of leaving one behind like you have experienced.

So it is definitely not something you have caused, it would have happened to me too. The difference is only that I have some practice in solving it