FlexContainer moving right

HTML

<button onclick="$('.save-footer').slideDown('medium', function() {
  if ($(this).is(':visible'))
    $(this).css('display', 'flex');
})">
  Popup
</button>

<div class="save-footer slider">
  <div class="div-section">
    <p id="save-footer-text">Your changes have not been saved.</p>
  </div>
  <div class="div-section">
    <button onclick="Save()" class="btn btn-info">Save</button>
  </div>
</div>

CSS

.save-footer {
  z-index: 9998;
  position: fixed;
  bottom: 0;
  height: 3em;
  background: rgb(255, 247, 125);
  color: black;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.5em;
  display: none;
}