How to center the formula in Obsidian

Hi, everyone. I have a problem with the formula’s centering.
In Obsidian, I have written the following command:

$$
\begin{aligned}
 P(x)\bigg|_{x\to\infty} \sim \frac{C_{\pm}}{x^{1+\mu}}.
\end{aligned}
$$

which is transformed as:
居中

It is not centered. Thus, how to solve this problem?