I am sorry, I might not have been very clear, your suggestion is for the “pane” background that I have got to display following the w3 explanation, what I need is the tab (link) background color when its content is displayed, like the example at the end of w3’s page.
The problem is that on the w3c page the tab links at the top of the content are contained within each target div. That means when the div is a target you can style the link because its a child of that target div.
In your example you have moved the side column links out of each block into their own block which means that there is no way to target the active item because the focus has moved to the target div which is somewhere else.
Either put each side link in each tab pane and then absolutely place it back where you want it or as mentioned above use JS/jquery to add a class to the currently clicked item.
Thank you.
I kinda had the feeling that was the problem, and was hoping there would have been a solution, which from your explanation I see there is not.
I had gone googling for the js/jquery solution, while you kindly had posted this solution.
Indeed I had to check specificity to make it work, which is something I googled for to understand your comment.
Once again thank you very much for your patience, and kindness.