使用CSS移动前景图像

我正在尝试使用CSS移动前景图像,因此它与背景图像重叠一点.我似乎无法让前景图像移动到任何地方,我只是无法弄清楚我做错了什么.谁能指出我正确的方向？看我的小提琴.

HTML:

CSS:

body{
 background: black;
}
.background{
  position: absolute;
  left: 0px;
  top: 0px;
  z-index: -1;
}
.frontImg{
  position: absolute;
  left:200;
  top:500;
  z-index: 1;
}

Sebastian Br.. 6

您缺少高度和宽度的单位(%,em,px等) .frontImg

body{
  background:black;
}
.backgroundImg {
  position:absolute;
  left:0px;
  top:0px;
  z-index:-1;
  -webkit-mask-image: -webkit-gradient(linear, left top, left bottom, from(rgba(0,0,0,1)), to(rgba(0,0,0,0)));
}
.frontImg{
  position:absolute;
  left:200px;
  top:100px;
  z-index: 1;
}

body{
  background:black;
}
.backgroundImg {
  position:absolute;
  left:0px;
  top:0px;
  z-index:-1;
  -webkit-mask-image: -webkit-gradient(linear, left top, left bottom, from(rgba(0,0,0,1)), to(rgba(0,0,0,0)));
}
.frontImg{
  position:absolute;
  left:200px;
  top:100px;
  z-index: 1;
}