Change font and size

Click on the blue CustomizeIt button on your admin menu bar on the top. Click on Custom CSS and paste the code given below:
body {
margin-bottom: 150px;
font-size: 17px;
font-family: Georgia, Helvetica, Arial, sans-serif;
color: #3f3f3f;
line-height: 28px;
background-color: white;
}
code, pre {
padding: 0 3px 2px;
font-family: Georgia, Helvetica, Arial, sans-serif;
font-size: 17px;
-webkit-border-radius: 3px;
-moz-border-radius: 3px;
border-radius: 3px;
}
The body { part of the code given above changes the font, its color and size on your blog.
The code, pre { part changes the font and size of your links in the post.
You can play with the font size, font-family, color and line-height values to get what you desire.