I am doing an online course on frontend, I have just started getting to know bootstrap 4 and flexbox. As far as I understand, to do inline styling is something that is considered bad practice. What I mean is this:
<button style="color: white; border: 5px solid red;"> Press me! </button>
And I like that the good practice is to not do this, mainly because of readability. What I don't understand is why the button above is not a good practice but the code here is considered good practice
<button class="btn btn-primary btn-lg d-flex justify-content-center> Press me! </button>
Just to clarify I do understand that the style that I used in the example doesn't do the same thing as the one using bootstrap. I am just interested in why one is OK and the other one is not.
The only thing that I have come up with is that since bootstrap is using class="" it's probably not inline styling.