How to style bootstrap container in wordpress theme?

Why do you need container inside container? You may use single container and to reduce it’s total width, you may specify that in your stylesheet like this:

.container{max-width:90%;width:800px}

I am just considering 800px width as your requirement. You may use your own values. The purpose of defining the max-width will be to make it responsive for mobile views as small devices do have width less than 800 but with explicit max-width, they won’t go wider than 90% of the respective screen sizes.

And, as per your code, why are you defining height of the container div? To increase spacings, you may use padding and margins. This explicitly height definition will unnecessarily increase your workload to rewrite the same for other mobile devices too.