In Chrome, the displayed text has a minimum font-size 12px even thought you set a smaller value in CSS. This is because the Chrome browser has a auto font adjustment.

So if you want to style a text with font-size smaller than 12px, include the following line in your CSS file.

body {
  -webkit-text-size-adjust: none;
}

Done =)

Reference: StackOverflow – Font-size <12px doesn't have effect in Google Chrome