html move to middle of page code example

Example 1: align in the middle of page html

.centered {
  position: fixed;
  top: 50%;
  left: 50%;
  /* bring your own prefixes */
  transform: translate(-50%, -50%);
}

Example 2: how to put container in center of page

#container
{
    width: 400px;
    margin-left: auto;
    margin-right: auto;
}