Selectors Reference Part 5

/*
  CSS Selectors
  - :root
  - :checked
  - :empty
  - :disabled
  - :required
  - :focus
  - ::selection
  - ::placeholder
*/

* {
  box-sizing: border-box;
  margin: 0;
}
body {
  font-family: Arial, Helvetica, sans-serif;
}