1.实现

2.代码

html

  <div class="addF">＋</div>

css

.addF{
    width:40px;
    font-size:25px;
    font-weight:600;
    background-color:rgb(64, 158, 255);
    text-align:center;
    color:white;
    height:34px;
    border-radius:3px;
    line-height:34px;
}