* {
  border: 0;
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background-color: #212121;
  color: white;
  font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

section { 
  display: none;
  height: 100vh;
  flex-wrap: wrap;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
[index="1"] { display: flex; }

h3 { font-size: 32px; }

.btnRow {
  flex-direction: row;
}

button {
  background-color: transparent;
  margin: 5px;
  padding: 5px;
  color: white;
  border: 3px solid white;
  border-radius: 8px;
  font-size: 16px;
}

button:hover {
  cursor: pointer;
}