html, body {
  height: 100%;
}
.wrapper {
  display: table;
  height: 100%;
  width: 100%;
}
.content {
  display: table-row;
  height: 100%;
}
.footer {
  display: table-row;
}

html, body {
  height: 100%;
}
.wrapper {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  align-items: stretch;
}
.content {
  flex-grow: 1;
}
.footer {
  flex-shrink: 0;
}

Make footer at bottom with Flex
Make footer at bottom with Flex
