Details matter in the viva but you don’t need to have perfect recall of everything you’ve ever read, done or written.
Details matter but you can take your time to think about how to explain them.
Details matter but you have lots of time to focus in advance of the viva on the details that matter more.
Details matter but your examiners want more than the facts.
Details matter but you need to be able to talk about them, not simply know them.
