overflow-x:hidden still can scroll

html, body {
  margin: 0 auto;
  overflow-x: hidden;
}

html{
  padding: 0;
}

body {
  width: 950px;
}

.full {
  background: red;
  color: white;
  margin-right: -3000px !important;
  margin-left: -3000px !important;
  padding-right: 3000px !important;
  padding-left: 3000px !important;
}

<div>
  <div class="full">
    abc
  </div>
</div>