.main_top_left{
    float:left; width:400px;
}
.main_top_center{
    float:left; width:327px;margin-left:16px;
}
.main_top_right{
    float:left; width:241px; margin-left:16px;
}
.main_bottom_left,.main_bottom_center,.main_bottom_right{
    float:left; width:322px;
}
.main_bottom_center,.main_bottom_right{
    margin-left:17px;
}