* { padding:0; margin:0; } .box { background:#ccc; height:50px; margin:0 auto; } .left { width:150px; float:left; margin-right:-150px; height:100%; background:#f00; position:relative; z-index:2; font-size:30px; line-height:50px; text-align:center; color:#fff; } .right { font-size:30px; line-height:50px; text-align:center; color:#fff; width:100%; float:left; height:100%; background:#ff9800; padding-left:180px; box-sizing:border-box; }