Tips:
1.第二个属性值必须跟上单位(s)
2.谁要过渡给谁加
图标转换最终效果:当鼠标划过图标时,缓慢转换成另一个图标
<body>
    <section class="logo">
        <div class="both">
            <div class="left">?</div>
            <div class="right">?</div>
        </div>
    </section>
</body>
.logo {
            width: 56px;
            height: 56px;
            margin: 20px auto;
            background-color: rgb(255, 111, 55);
            line-height: 56px;
            border-radius: 16px;
        }
        .both {
            width: 112px;
            height: 56px;
            font-family: ‘icomoon‘;
            font-size: 45px;
            text-align: center;
        }
.left,
        .right {
            float: left;
            padding: 0 5px;
        }
    .logo:hover .both {
            margin-left: -56px;
        }


        .logo {
            width: 56px;
            height: 56px;
            margin: 20px auto;
            background-color: rgb(255, 111, 55);
            line-height: 56px;
            border-radius: 16px;
            overflow: hidden;
        }
        
        .both {
            width: 112px;
            height: 56px;
            font-family: ‘icomoon‘;
            font-size: 45px;
            text-align: center;
            transition: all .7s;
        }


原文:https://www.cnblogs.com/ben-studying/p/14645026.html