calculator/src/index.css

html {
  height: 100%;
  font-size: 10px;
}

body {
  background-color: black;
  margin: 0;
  padding: 0;
  font-family: sans-serif;
  height: 100%;
}

#root {
  height: 100%;
}

body .github-fork-ribbon:before {
  background-color: #333;
}

@media screen and (max-width: 400px) {
  .github-fork-ribbon {
    display: none;
  }
}

@media (min-width: 400px) and (min-height: 400px) {
  html {
    font-size: 20px;
  }
}

@media (min-width: 500px) and (min-height: 500px) {
  html {
    font-size: 30px;
  }
}

@media (min-width: 600px) and (min-height: 600px) {
  html {
    font-size: 40px;
  }
}

@media (min-width: 800px) and (min-height: 800px) {
  html {
    font-size: 50px;
  }
}