Here is another quick silent movie (it's 2:00 AM here family sleeping) demonstrating changing the background colour and the text -link-colours

https://youtu.be/E8-h94XW_S4

Thanks so much Wayan you have been very helpful and that worked just great!

Could I sneak in another question while we are here?

I want to add a main container, to hold all of the various other containers with content, the header, the nav bar and teh content div, footer etc. So Ive created a new div, set eht width and centered it and now cannot get any of those other divs into this main one! I can't drag them in, can't cut and paste, can't do it via the Elements Tree. Seems no way to move them into it at all. Surely this is possible? What am i missing this time?

So much to lear... so little time!

Thank eeryone for helping

You have to have SD open so that you see the right-most tool pane, which has the element tree at the top.
Click on the red button where it says Collapse all nodes.
Make sure you select the body, so that you don't end up inside some now buried container.
Then go to the left-most tool pane and add a container div. Most likely it will end up below all the others.
We have different preferences about how to proceed from there. My way is like this:
Back on the right-most one:
You may possibly collapse all nodes again. Then you see what you have to move, it should hopefully not be too much if they are all collapsed.
Make sure the new container is open (wee arrow pointing down)
Grab the last one of those that are to go into the new container, and drag it down until it is aligned with the text of the new container, then let go of it. Now it should be inside.
Take the next container and do the same. Then it should land above the first one you moved.
Continue like that until you've got them all inside.

It takes longer to explain than actually to do.

May I say at this moment regarding the html5 schematic layout stuff and the container tag "main" that this container should NOT contain the header tag or the nav container. There is also another reason and that is to do with the sticky class if you are considering having your header and or nav container with the sticky position then they need to be outside of the main container in order to work properly.
Regarding adding a container then placing others inside as Inger says there are numerous ways to achieve this, I could do another demo video but it would have to be with sound so it would have to be later as it's 3:00 am here at this moment and family still throwing zzzzzzzzzzzz out. If you still having problems let us know and we can try help out more

Excellent, Wayan, I didn't think that far. Bit stressed at the time being...

I know

Thanks very much again Wayan, I thought that the tip to make sure that the little arrow in the Elements Tree window was pointing down might be it, but no. The other containers just wont behave.

I tried this just to see what's happeneing here:

Added a new container to the body, it landed under the others as you suggested. I then tried to add my header and or nav containers to it (I didnt give it any class first, not 'main' for sure, thanks for that tip) but neither will go into the new container. So I tried to add a carosel into the new container and it too wont go in, no matter which way I try to do it.
Im wondering if there is a tag that Ive used elsewhere than means I cant nest containers? Or perhaps the carosel container already as the maximum number of nested containers, if there is such a max value?
I tried to simplfy things just in case there is a max value by adding a simple 2 column container to the new one, no good, it also wont nest in the new container. What could this be?
I can add a link container to the new one, but little else. Im happy that Im not doing anything stupid!

In what part of the world are you? (I am asking only so I know about the time differences)
I am a little confused as to what you are trying to achieve
First
I have to ask why are you trying to enclose the Nav/header into another container ?

Here is another demo video, (with sound this time) showing adding/moving containers around and elements also


https://youtu.be/pUtv2GVSiC4

Wayan.
Thank you for your video showing adding/moving containers around and elements also. Watching showed me why sometimes a container ended up where I wanted it and sometimes it didn't. Also the tip to close the Grid selector before starting to move/add elements was a bonus. Many thanks. I know I'll be rewatching your video over and over.