gregorianin

.wrapper{
  background-color: #fff;
  height: 3000px;
}

.wrap-2 {
  width: 100vw;
  height: 20vh;
  position: absolute;
  bottom: -50%;
  background-color: red;
 
  animation: go 1s linear  forwards;
}

@keyframes go{
  100%{
    position: fixed;
    bottom: 0;
  }
}