html {
  font-size: clamp(1em, 1em + 1.5vw, 1.75em);
  height: 100%;
}

body {
  min-height: 100%;
  display: grid;
  grid-template-rows: auto 1fr;
}

h1 {
  font-size: medium;
}

h2 {
  font-size: inherit;
}

header {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
}

button {
  background: plum;
  border: thin solid mediumvioletred;
  cursor: pointer;
  border-radius: 0.25em;
}

button:hover,
button:focus,
button:active {
  border-color: rebeccapurple;
}


button[aria-pressed='true'] {
  background: mediumvioletred;
  border-color: rebeccapurple;
  color: white;
}