走马灯左右箭头

        <button type="button" class="el-carousel__arrow el-carousel__arrow--left" @click="stepChange">
            <i class="el-icon-arrow-left"></i></button>
        <button type="button" class="el-carousel__arrow el-carousel__arrow--right" @click="next">
            <i class="el-icon-arrow-right"></i></button>

.el-carousel__arrow:hover {
    background-color: rgba(31, 45, 61, .23);
}

.el-carousel__arrow--left {
    left: 16px;
}

.el-carousel__arrow--right {
    right: 16px;
}