#my-anchor-update {
  anchor-name: --my-anchor-update;
}

#my-anchor-update[data-small] {
  width: 100px;
}

#my-anchor-update[data-large] {
  width: 400px;
}

#my-target-update {
  position: absolute;
  right: anchor(--my-anchor-update right);
  top: anchor(--my-anchor-update bottom);
}