body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  margin: 0;
  font-size: 16px;
}
main {
  margin: 0 auto;
  max-width: 60ch;
  display: flex;
  min-height: 100vh;
  flex-direction: column;
  padding-inline: 1rem;
  font-size: 1.25rem;
}

.header {
  text-align: center;
}

.content {
  flex: 1;
}

.footer {
  padding-block: 1rem;
  text-align: center;
  font-size: 1rem;
}

a.skip-main {
  left:-999px;
  position:absolute;
  top:auto;
  width:1px;
  height:1px;
  overflow:hidden;
  z-index:-999;
}
a.skip-main:focus, a.skip-main:active {
  color: #fff;
  background-color:#000;
  left: auto;
  top: auto;
  width: 30%;
  height: auto;
  overflow:auto;
  margin: 10px 35%;
  padding:5px;
  border-radius: 15px;
  border:4px solid yellow;
  text-align:center;
  font-size:1.2em;
  z-index:999;
}