css 生成图片添加的十字

<span class="add" title="继续上传">
</span>

.add {
display: inline-block;
width: 76px; height: 76px;
color: #ccc;
border: 2px dashed;
text-indent: -12em;
transition: color .25s;
position: relative;
overflow: hidden;
}
.add:hover {
color: #34538b;
}
.add::before, .add::after {
content: '';
position: absolute;
top: 50%;
left: 50%;
}
.add::before {
width: 20px;
border-top: 4px solid;
margin: -1px 0 0 -10px;
}
.add::after {
height: 20px;
border-left: 4px solid;
margin: -10px 0 0 -2px;
}