Answers for "how to put a element in center of a page"

center div in middle of page

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

position absolute center

position: absolute;
margin-left: auto;
margin-right: auto;
left: 0;
right: 0;
text-align: center;