html, body {
  font-family: system-ui, sans-serif;
  height: 100%;
  margin: 0;
  display: flex;
  flex-direction: column;
  padding: 0;
  line-height: 1.6;
}

header {
  background: rgba(5,126,111,255);
  color: white;
  padding: 2rem;
  text-align: center;
}

header .btn {
  display: inline-block;
  background: white;
  color: rgba(5,126,111,255);
  padding: 0.5rem 1rem;
  text-decoration: none;
  font-weight: bold;
  border-radius: 4px;
}

main {
  padding: 2rem;
  flex: 1;
}

footer {
  background: #f4f4f4;
  padding: 1rem;
  text-align: center;
}