<main>
  <h1>I'm styled by CSS Variables</h1>
  <h2 class="fallbacks">I'm using Fallbacks</h2>
  <h2 class="no-fallbacks">I'm not using Fallbacks</h2>
</main>

@import url('https://fonts.googleapis.com/css2?family=Atkinson+Hyperlegible:wght@700&display=swap');

:root {
  --primaryColour: hsla(4, 99%, 66%, 1);
  --secondaryColour: hsla(155, 61%, 51%, 1);
  --secondaryBackgroundColour: hsla(343, 6%, 21%, 1);
  --backgroundColour: hsla(207, 100%, 96%, 1);
}

* {
  box-sizing: border-box;
}

main {
  display: grid;
  place-content: center;
  min-height: 100vh;
  background-color: var(--backgroundColour);
  padding: 3em 5em;
}

h1 {
  font-family: 'Atkinson Hyperlegible', sans-serif;
  letter-spacing: -0.5px;
  font-size: 3rem;
  color: var(--primaryColour);
  text-align: center;
}

h2 {
  font-family: 'Atkinson Hyperlegible', sans-serif;
  letter-spacing: -0.5px;
  font-size: 2.25rem;
  padding: 1.25rem 3rem;
  text-align: center;
}

.fallbacks {
  color: var(--thisDoesntExist, lightgreen);
  background-color: var(--thisDoesntExist, black);
}

.no-fallbacks {
  color: var(--secondaryColour, lightgreen);
  background-color: var(--secondaryBackgroundColour, black)
}

@media (max-width: 425px) {
  h1 {
    font-size: 2.5rem;
  }
  
  h2 {
    font-size: 2rem;
  }
}