Maybe this tutorial can help you.
For your code in a box: read below the form where you write your message, it says: “Allowed markup: a blockquote code em strong ul ol li.
Put code in between backticks
“
So put your code between backticks and it’ll appear as follows:
p.column1, p.column2, p.column3{
float: left;
width:30%;
}
p.column1 {
background-color: transparent;
background: url('themes/images/bgback1.jpg') no-repeat top;
background-attachment: scroll;
background-x-position: 0%;
background-y-position: 0%;
background-repeat: no-repeat;
width: 115px;
margin-top: auto;
margin-right: 45px;
margin-bottom: auto;
margin-left: auto;
padding-left: 10px;
padding-right: 20px;
padding-top: 0px;
padding-bottom: 10px;
}
BTW: the backtick is on the left side of the 1, above the tab on my keyboard ??