flex 居中并两端对齐

<h3><span>投资金额</span><span>美通卡奖励</span></h3>

h3{
    width:100%;
    height: 0.8rem;
    /* line-height: 0.85rem; */
    display: flex;
    align-items: center;
    justify-content: space-between;
}