CSS div的重叠

.div1 {
  position: relative;
  z-index: 1;
}

.div2 {
  position: relative;
  z-index: 2;
}

.div1 {
  position: absolute;
  z-index: 1;
}

.div2 {
  position: absolute;
  z-index: 2;
}

.div1 {
  position: fixed;
  z-index: 1;
}

.div2 {
  position: fixed;
  z-index: 2;
}

.div1 {
  position: sticky;
  z-index: 1;
}

.div2 {
  position: sticky;
  z-index: 2;
}