What I don’t understand is how to create the the gray block with content and the tabs menu inside it. Since I can’t wrap the tabs menu with a div, I have no idea how to do this. Is it even possible?
Set the Tabs-menu to Flex vertical, give it some padding and design the links the way you like.
You can place the header inside the first tab link, as you cannot place any element in the Tabs-menu element.