demo-container { display: block; border: 2px solid rgb(189, 189, 189); padding: 25px 10px 10px; border-radius: 4px; width: 250px;height: 202px; }
demo-object { display: block; background-color: rgb(224, 255, 253);  }
.element {position-try: most-height --custom-bottom;}

.anchor {
font-size: 1.8rem;
color: white;
text-shadow: 1px 1px 1px black;
background-color: hsl(240 100% 75%);
width: fit-content;
border-radius: 10px;
border: 1px solid black;
padding: 3px;
}
.anchor {
anchor-name: --demo-anchor;
position: absolute;
top: 100px;
left: 45%;
}
.infobox {
color: darkblue;
background-color: azure;
border: 1px solid #dddddd;
padding: 10px;
border-radius: 10px;
font-size: 1rem;
text-align: center;
}

form {
position: fixed;
bottom: 2px;
right: 2px;
}
@position-try --custom-bottom {
top: anchor(bottom);
bottom: unset;
margin-top: 10px;
}
.infobox {
position: fixed;
position-anchor: --demo-anchor;

bottom: anchor(top);
margin-bottom: 10px;
justify-self: anchor-center;

position-try: most-height --custom-bottom;
}