3 columns layout, all float

Hello,

I am trying to achieve the following :

Column A Sidebar 1 Sidebar 2
Fluid Fixed 180 px Fixed 180 px

So here is what I have done from a code point of view :

#container /* the container contains the free float */
{
margin-bottom: 5px;
}
 
#columna
{
float:left;
margin-left: 10px;
margin-right: 400px;
}
 
#sidebar1
{
float: right;
width: 180px; /* sidebar content width */
}
 
 
#sidebar2
{
float: right;
width: 185px; /* sidebar content width */
}

The issue is that sidebar 1 and sidebar 2 are always displayed under column A instead of being next to it

I have made some researches on the forum but I cannot find a similar design, usually, it is the center container that is "liquid".