Сетки / Испытание: строим сетку 27/32

Подскажите пожалуйста с советом как можно оптимизировать…

 <body>
    <div class="header" >
        <div class="layout-positioner">Header</div>
    </div>
    <div class="menu" >
        <div class="layout-positioner">Menu</div>
    </div>
    <div class="promo" >
        <div class="layout-positioner">
            <div class="layout-column">Promo 1</div>
            <div class="layout-column">Promo 2</div>
         </div>
    </div>
    <div class="column">
        <div class="layout-positioner">
            <div class="layout-column">Left</div>
            <div class="layout-column">Main</div>
            <div class="layout-column">Right</div>
         </div>
    </div>
    <div class="footer">
        <div class="layout-positioner">Footer</div>
    </div>
</body> 

html,

body {
margin: 0;
padding: 0;
}

body {
width: 450px;
height: 335px;
font-family: “Arial”, sans-serif;
font-size: 10px;
color: white;
}
.header, .promo{
background-color: #34495e;
min-height:45px;
padding-top:10px;
}
.menu, .column .layout-column{
background-color:#3498DB;

}
.header .layout-positioner{
background-color:#c0392b;
width:100px;
padding: 5px;
width: 340px;
min-height:25px;
}
.menu .layout-positioner{
padding:5px;
width:340px;
min-height:25px;
}

.promo .layout-column{
background-color:#c0392b;
min-height:50px;
width: 160px;
padding: 5px;
margin-bottom:10px;
}
.column .layout-column{
background-color:#3498DB;
min-height:100px;
width: 180px;
margin-top:10px;
margin-bottom:10px;
padding:5px
}
.column .layout-column:last-child{
width: 60px;
}
.column .layout-column:first-child{
width: 60px;
margin-right: 10px;
}
.layout-positioner{
margin:0 auto;
width: 350px;

}
.layout-column{
float:left;

}
.footer{
min-height: 35px;
background-color:#34495e;
}
.footer .layout-positioner{
padding: 5px;
width: 340px;

}
.layout-column:last-child{
float:right;
}
.layout-positioner::after {
display: table;
content: “”;
clear: both;
}