You don't need any font size in the main body text.. stick with the default font size.
This is the code I use.
Code:
body {
widows: 1;
orphans: 1;
margin-top: 0;
margin-right: 0;
margin-bottom: 0;
margin-left: 0;
text-align: justify;
}
p {
margin-top: 0;
margin-bottom: 0;
text-indent: 1.2em
}