/* universal box-sizing with inheritance */
html {
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}

/* establish root-em, select font stack */
html {
  font-size: 18px;
  /* this font stack is what github.com uses as of 2019-06-23; I trust them to
   * have put more thought into this than most others */
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Helvetica', 'Arial', sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';
}

/* kill all predefined margins */
* {
  margin: 0;
  border: 0;
  padding: 0;
}