效果图

纯css效果实现

<div class="content_box">
   <input type="checkbox" id="exp">
    <div class="content word" line-clamp="2"> 
        <label class="btn" for="exp">
			<i class="iconfont icondown"></i>
		</label>
        {{orderInfo.originalContent}}
    </div>
</div>


.content_box{
    display: flex;
    flex: 1;
}
.word{
    flex: 1;
    font-size: 14px;
    font-family: PingFangSC-Regular, PingFang SC;
    font-weight: 400;
    color: #303133;
    line-height: 24px;
    overflow: hidden;
    // display: -webkit-box;
    // -webkit-box-orient: vertical;
    // -webkit-line-clamp: 2;
    line-height: 1.5; /*根据实际调整行高，最大高度*/
    max-height: 3em;
    // transition: .3s max-height;
    span{
        display: inline-block;
    }
    &::before{
        content: '';
        float: right;
        width: 0px;
        height: calc(100% - 21px);
    }
    &::after {
        content: '';
        width: 100%;
        height: 20px;
        position: absolute;
        background: #fff;
    }
    .btn {
        color: #3F66FF;
        float: right;
        clear: both;
        margin-top: 0px;
        margin-right: 13px;
        cursor: pointer;
        position: relative;
        .icondown{
            position: absolute;
            bottom: -4px;
            right: -17px;
            font-size: 18px;
            color: #3F66FF;
        }
    }
    .btn::before{
        content: '...';
        position: relative;
        left: -6px;
        top: 1px;
        color: #303133;
        transform: translateX(-100%)
    }
    .btn::after{
        content:'展开' /*采用content生成*/
    }
}
// 默认展示二行
[line-clamp="2"] {
    max-height: 3em;
}
#exp{
    display: none;
}
#exp:checked+.word{
    // max-height: none;
    max-height: 800px; /*超出最大行高度就可以了*/
}
#exp:checked+.word .btn::after{
    content:'收起'
}
#exp:checked+.word .btn::before {
    visibility: hidden; /*在展开状态下隐藏省略号*/
}
#exp:checked+.word::after{
    visibility: hidden;
}
#exp:checked+.word .btn{
    .icondown{
        transform: rotate(180deg);
    }
}