div { font-family: Oswald;
    color: #333;
    text-align: center;
    text-transform: uppercase; }

.wrapper:after { content: " ";
               display: table;
               clear: both; }

.section { height: 200px;
         margin-bottom: 10px;
         float: left;
         width: 33.333333%; }

.b2 { background-color: #dddd; }

.b1, .b3 { background-color: #ccc; }
.b4 { background-color: #c8d5f0;
    width: 240px;
    margin-top: 50px;
    clear: both; }
#header, 
#footer { 
    clear: both;
    width: 100%;
}