Solution (source code)

= Solution

A <Hermitian matrix> has $A^*=A$. Choose
$$
\boxed{A=\begin{pmatrix}1&i\\-i&2\end{pmatrix},\qquad\det A=1.}
$$
Its off-diagonal entries are <complex conjugates> and its diagonal entries are real, so the defining condition holds. It is also invertible.