Grid

grid.css

.g-row {
   max-width:1200px;
   *width: 960px;
   overflow: hidden;
}

.g {
   float: left;
   padding-left: 10px;
   padding-right: 10px;
   -webkit-box-sizing: border-box;
      -moz-box-sizing: border-box;
       -ms-box-sizing: border-box;
        -o-box-sizing: border-box;
           box-sizing: border-box;
}


.g-25pc {
   width: 25%;
   *width: 220px; /* + 10*2 = 240 */
}

.g-50pc {
   width: 50%;
   *width: 460px; /* + 10*2 = 480 */
}

.g-75pc {
   width: 75%;
   *width: 700px; /* + 10*2 = 720 */
}

.g-100pc {
   width: 100%;
   *width: 940px; /* + 10*2 = 960 */
}

html.html

<div class="g-row">
<div class="g g-50pc"> </div>
<div class="g g-50pc"> </div>
</div>