navbar not navbar-fixed-top

Hi, i want to add some content above the navbar, so i doesnt add the class navbar-fixed-top in NavBar::begin code.

Problem is, when the navbar is not fix at top, there are a lot of empty space between the navbar and the breadcrumb.

I found that the breadcrumb is wrap by a div with class="container".

After doing some testing, i found any div with class container has some empty space on top of the div content.

I check yii2 bootstrap.css but cant find any clue.

So how to remove the empty space?