Center div vertically and horizontally without defined height [duplicate]

Answer 1

If you want a CSS only solution without specifying height:

• You can use css3 flexbox:

  body {
    display:flex;
    align-items:center;
  }
  

  Updated Fiddle

• Or you can use the translate technique:

  .card {
    position: absolute;
    top: 50%;
    left:50%;
    transform: translateX(-50%) translateY(-50%);
    /* other styles */
  }
  

  Updated Fiddle

browser support:

• flexbox @caniuse
• transform @caniuse

Side note: You might need js fallbacks if you want to support old browsers

Answer 2

You could do it by set top:50%; and transform: translateY(-50%); to .card

JSFiddle - DEMO or Full Screen View

CSS:

html, body {
    height:100%;
    margin: 0px;
}
.card {
    background-color: #1d1d1d;
    /* IE fallback */
    background-color: rgba(29, 29, 29, 0.95);
    color: #fff;
    padding: 30px 35px;
    outline: 2px solid #3B3A37;
    outline-offset: -9px;
    width: 320px;
    position: relative;
    margin: 0 auto;
    top:50%;
    -webkit-transform: translateY(-50%);
    -ms-transform: translateY(-50%);
    -moz-transform: translateY(-50%);
    -o-transform: translateY(-50%);
    transform: translateY(-50%);
}

For more info:

• W3.ORG - CSS Transforms Module Level 1

• Mozilla MDN - CSS Transform