Edit in JSFiddle

<div class="elem fixed">
    <span class="label begin"> &lt;div class="fixed"&gt; </span>
    <p>Hello！暂时不要太关注我哦。</p>
    <span class="label end"> &lt;/div&gt; </span>
</div>

.elem{
    border:solid #6AC5AC 3px;
    position:relative;
}

.label{
    position:absolute;
    background-color:#6AC5AC;
    line-height:1em;
    padding:3px;
}
.begin{
    left:0;
    top:0;
}
.end{
    right:0;
    bottom:0;
}
p{
    margin:2em 0;
    display:block;
}

.fixed {
  position: fixed;
  bottom: 0;
  right: 0;
  width: 200px;
  background-color: white;
}