Variance of a split Bernoulli inner product

Suppose $Z_1,Z_2,…,Z_{128}$ are i.i.d. $\mathrm{Bin}(1,0.5)$ random variables. Define $$\mathbf{X}=(Z_1,Z_2,…,Z_{64})^T\quad\text{and}\quad\mathbf{Y}=(Z_{65},Z_{66},…,Z_{128})^T.$$ Then the value of $\mathrm{Var}(\mathbf{X}^T\mathbf{Y})$ is