html,
body {
  min-height: 100%;
}

body {
  display: flex;
  min-height: 100vh;
  min-height: 100svh;
  flex-direction: column;
}

body > header,
body > footer {
  flex-shrink: 0;
}

body > main {
  flex: 1 0 auto;
}

body > footer {
  margin-top: auto;
}