* {
  font-size: medium;
}

#xx-small { font-size: xx-small; }
#x-small { font-size: x-small; }
#small { font-size: small; }
#medium { font-size: medium; }
#large { font-size: large; }
#x-large { font-size: x-large; }
#xx-large { font-size: xx-large; }
#smaller { font-size: smaller; }
#larger { font-size: larger; }

#reference #xx-small { font-size: 60%; }
#reference #x-small { font-size: 75%; }
#reference #small { font-size: 88.889%; }
#reference #large { font-size: 120%; }
#reference #x-large { font-size: 150%; }
#reference #xx-large { font-size: 200%; }
#reference #smaller { font-size: 83.333%; }
#reference #larger { font-size: 120%; }
#reference #smaller-smaller { font-size: 69.444%; }
#reference #larger-larger { font-size: 144%; }