_layout.scss

#page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

main {
  flex: 1 0 auto;
  width: 100%;
  max-width: 960px;
  margin: 3rem auto;
  padding: 0 1rem;
}

footer {
  flex-shrink: 0;
}