Well said!

Thanks for the car analogy, Keith!

So, which framework am I using?

It says "Foundation classes" at the top of the styles tab under "Class selector." Does this mean that I am using Foundation? Is Foundation the default setting?

If Foundation is a Ford or Chevvy, then good. I don't want to be building a Yugo.

With SD open, check the left top of your screen. There the framework is spelled out, with name, version and everything. Right below it you have the Foundation logo, and as if that were not enough, you will see the slider on a blue background, and also the breakpoints are blue. The other frameworks also have their specific colours:
Bootstrap - purplish
Materialize - pinkish
Vanilla - creamy

Nope, don't want no Yugo! So in the class selector it sats Foundation and then there are a bunch of canned Foundation classes that can be applied. So, if your down the road with Foundation and have no preference, then your fine. As far as SD picking Foundation, it appears that it is the default, at least it always opens to that on my machine.

It is the default because at one time you made it so
If you want to have the option of choosing whichever framework or themes to open
open site designer
on the top left nav, bar thingy open the "File" link
from the down menu choose "open from theme"
when the window opens

make sure you have selected "All" from the choices

Then bottom left there is a tick box
"don't show on startup"
make sure that is un-ticked
bottom right is another tick box
"make default"
either un-tick it then choose what you want site designer to open for that particular project then select the button "Choose" thereafter whenever you open site designer you will get the window that allows you to choose what framework or theme to open for any project
to have the window show you all the options
or
select a framework/theme
tick the box "Make default"
tick the box "don't show on startup"
then the button "choose"
thereafter site designer will open with whichever thingy you made default straight away with no options.

but you can always change by opening the "open from theme" and selecting something for just that one time

So the choice for the default is yours to make

[quote=Keith Van Wemmer]

What's wrong with a Yugo?

In the right hands a Yugo can be made to look and perform like a Mercedes AMG or a Lincoln Continental or even a Ferrari

Thank you for pointing out those differences, Inger. Foundation it is!
I will probably never invest the time to get very deep into Site Designer. I just want to have control over my own websites. But it is nice to know that going further is an option.

Keith, I appreciate your feedback!

So, this (thread)circle is round. Foundation is OK if you don't want to include Material classes. But if you wouldn't know if you didn't know anything about Frameworks