.header {
  height: 300px;
  background: #fff url(https://images.cnblogs.com/cnblogs_com/zwywilliam/903701/o_gamescibanner.jpg) no-repeat fixed top center;
  background-size:1920px 643px;
  border-bottom: 0px solid #000000;
  padding-left: 30px;
  padding-top: 30px;
  color: #ffff00;
}

#leftcontent {
  position: absolute;
  top: 300px;
  left: 10px;
  width: 200px;
  background-color: ;
  border: 0px solid #000000;
  border-top: 0px solid #000000;
  border-right: 1px solid #DDDDDD;
  font-family: Arial;
  font-size: 12px;
}