A delivery note has its own style sheet ( but related to your invoice style) which you can not separately customise. It is not 100% the same because it is a delivery note. At the moment there is no way to separately modify it, I think. But I can see that your logo is to big that is the reason why your invoice detail container is partly over your logo. You can change the size of your logo in invoice customisation or in the css editor.
To your other question
When viewing the delivery note, there’s a message above it in red highlight saying ’ You’ve applied a temporary style to this document. [To remove it click here]’. Clicking it just returns to invoice view…???
It is a kind of a draft. If you click on the red bar it removes the delivery note draft from the invoice. At the bottom is the option to save the draft to your invoice. If you click ‘back’ in your browser it will also be saved to the invoice. To avoid this because you don’t want the delivery note linked to the invoice they created this red bar that everybody can see this straight away.
Edit: You may can customise your delivery note. Please read here
I hope this helps