<div class="parent">
<div class="div1"></div>
<div class="div2">
<span class="tag"></span>
</div>
</div>
.parent {
width: 200px;
display: flex;
border: 1px solid pink;
}
.tag {
border: 1px solid skyblue;
}
ask CSS to achieve the effect shown in the picture
ordinary ellipsis will definitely fail. If omitted on div2, the right side of blue border will also be truncated and will have no effect on tag.