css font size

1.class {
2	font-size: 12px;
3}

1<span style="font-size:20px;"></span>

1p {
2	font-size: 150% /*px, cm, in, etc.*/; 
3}

1font-size: 2em;

1#selector{
2    font-size:20px;
3}

1// to scale font size in relation to its parent element
2style="font-size: 2vw;"