8. If $\forall x \in(-\infty,-1)$, the inequality $\left(m-m^{2}\right) 4^{x}+2^{x}+1>0$ always holds, then the range of real number $m$ is $\qquad$
Let $t=2^{x} \in\left(0, \frac{1}{2}\right), f(t)=\left(m-m^{2}\right) t^{2}+t+1>0$, since $f(0)=1>0$, so $f\left(\frac{1}{2}\right)=\frac{1}{4}\left(m-m^{2}\right)+\frac{3}{2} \geqslant 0 \Rightarrow m^{2}-m-6 \leqslant 0 \Rightarrow-2 \leqslant m \leqslant 3$.