Redundant special methods

[stasoid]

I again encountered some classes (css_position, background) with copy constructor/copy assignment operator that behave exactly as implicitly generated ones. I don't understand the purpose of those. Can I remove them?

Same for default constructors and destructors. I don't understand why ~background() = default; or css_borders() = default; are needed. Can I remove them?

[tordex]

Can I remove them?

Yes, it is safe to remove these.