css画加号➕减号➖

.plus,
.minus
{
    width: 11px;/* 大小 */
    height: 11px;/* 大小 */
    position: relative;
    display: inline-block;
}
.plus::before,
.minus::before
{
    content: ' ';
    position: absolute;
    left: 0;
    top: 0;
    bottom:0;
    margin:auto 0;
    width: 100%;
    height: 3px; /* 粗细 */
    background-color: white; /* 颜色 */
}
.plus::after {
    content: ' ';
    position: absolute;
    left: 0;
    right:0;
    margin: 0 auto;
    width: 3px; /* 粗细 */
    height: 100%;
    background-color: white; /* 颜色 */
} 

实现：