Is derived template class and base class layout compatible?

I have two classes:

struct Base
{
    int a;
};

template<typename T>
struct Derived : Base
{};

Are they layout compatible or not?

C++11 standard says ([class.mem]/16):

Two standard-layout struct (Clause 9) types are layout-compatible if they have the same number of non-static data members and corresponding non-static data members (in declaration order) have layout-compatible types.

But it also says ([class.derived]/8):

A base class subobject might have a layout (3.7) different from the layout of a most derived object of the same type.

And it confused me.

Note:

This check

static_assert(__is_layout_compatible(Base, Derived<int>), "");

passed on GodBolt (compiler - x86-64 gcc(trunk)).