Can't fit two blocks in a bootstrap row?

Question

Bootstrap

Here is the site gta5rp-info.ru

I made four blocks of col-md-3, in fact it should fit 4 blocks per line, but for some reason the fourth block moves down to the second line - how to fix it? Moreover, if I connect boostrap 3, and not 4, then there is no such problem. But using bootstrap 3 is not an option.

Answer 1

<div class="container-fluid">
  <div class="row">
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
    <div class="col-md" style="display:inline-block;">
  <div style="background:#fff; height:500px;">
  </div>
    </div>
  </div>
</div>