index.css

/*
Combo of:
https://www.swyx.io/css-100-bytes/
https://stackoverflow.com/questions/643879/css-to-make-html-page-footer-stay-at-bottom-of-the-page-with-a-minimum-height-b/20352949#20352949
*/

html {
  line-height: 1.75;
  font-size: 1.25em;
}

body {
  height:100vh;
  margin: auto;
  /* margin:0; */
  max-width: 70ch;
  display:flex; 
  flex-direction:column;
}

article {
  padding-left: 0.5em;
}

header{
  min-height:50px;
  background:lightcyan;
  padding-left: 0.5em;
  border-bottom-left-radius: 10px;
  border-bottom-right-radius: 10px;
}

footer{
  min-height:50px;
  background:PapayaWhip;
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
  text-align: center;
  margin-top:auto; 
}

button {
  align-self: flex-start;
  box-shadow: 2px 2px 2px #faa;
}