What units do I add after a value in the Style builder?
You don’t have to add units unless you want to use a specific unit or you’re adding Custom CSS properties.
Acquia Cohesion renames to Site Studio from version 6.2. Tell me more.
The Youtube video embed is responsive so it should expand to the width of its parent. If you do need to set a width you can apply the Width CSS property through the Style Builder.