If you are looking for maintaining uniformity across multiple products or domains, you can define the pages layout. To define the same, go to:
Campaign>Manage store layout
Step 1 : The page below will open up on clicking "Manage Store layout". Here, you will be able to define the page layout which you want to remain uniform across all products and domains. Once you hover your mouse on the layout page, you will get 2 options:
You can edit the page as per your needs and can save the same to set the layout as default.
Step 2: Apart from it, you can also define the Cart page, Checkout page and Thank you page which is going to be uniform across all the domains. Clicking on Update will save the changes.