body {
    background-color: antiquewhite;
}

body {
    background-color: rgba(red, green, blue, pointer);
}

h1 {
    font-size: large;
    color: red;
    cursor: pointer;
    font-weight: 200;
    font-family: sans-serif;
    text-align: center;
    margin-top: 50px;
    border: salmon;
}

button {
  font-family: "helvetica neue", helvetica, sans-serif;
  letter-spacing: 1px;
  text-transform: uppercase;
  border: 2px solid rgb(200 200 0 / 60%);
  background-color: rgb(0 217 217 / 60%);
  color: rgb(100 0 0 / 100%);
  box-shadow: 1px 1px 2px rgb(0 0 200 / 40%);
  border-radius: 10px;
  padding: 3px 10px;
  cursor: pointer;
}

html {
 font-family: sans-serif;
 }

 body {
    width: 50%;
    max-width: 800px;
    min-width: 480px;
    margin: 0 auto;
  }

  .form input[type="number"] {
    width: 200px;
  }
  .lastResult {
    color: white;
    padding: 3px;
  }