.list {
  position: relative;
}
.list-item {
  position: relative;
  background: #ddd;
  border: 1px solid #eee;
  margin-bottom: 20px;
}
.child {
  width: 100%;
  height: 100%;
  background: 'red';
}
.border-box {
  background: #5584ff;
}
.height-30 {
  height: 30px;
}