font-size: 
xx-small | x-small | small | medium | large | x-large | xx-large |
larger | smaller | 1em |20pt | 120% | inherit

• Relative sizes are with regard to any inherited value
• Rule of thumb, larger is about 1.2 times large etc

Size inherited:12pt 
Size xx-small 
Size x-small 
Size small  
Size medium 
Size large  
Size x-large 
Size xx-large 
This is some larger and some smaller  relative 120%  text
This is some larger and 
some smaller  relative 120%  text
Size 1em 
Size 12pt        Size 20pt