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<footer>Фиксированный подвал</footer>

body {
  background: #eaeaed;
  color: #fff;
  font: 600 14px/24px "Open Sans", "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", Sans-Serif;
}
footer {
  background: #2db34a;
  bottom: 0;
  left: 0;
  padding: 20px 0;
  position: fixed;
  right: 0;
  text-align: center;
}