Edit in JSFiddle

<div data-i2="css:['.fromCssClass','.toCssClass']">
    <span data-i2="rate:3">A</span>
    <span data-i2="rate:2">B</span>
    <span data-i2="rate:1">C</span>
</div>
<div data-i2="css:'fromCssClass,toCssClass'">
    <span data-i2="rate:3">A</span>
    <span data-i2="rate:2">B</span>
    <span data-i2="rate:1">C</span>
</div>
<div data-i2="css:[{'font-size':'10px','opacity':'0.7','color':'#888888'},{'font-size':'30px','opacity':'1','color':'#000000'}]">
    <span data-i2="rate:3">A</span>
    <span data-i2="rate:2">B</span>
    <span data-i2="rate:1">C</span>
</div>
<div data-i2="css:[{fontSize:'10px',opacity:0.7,color:'#888888'},{fontSize:'30px',opacity:1,color:'#000000'}]">
    <span data-i2="rate:3">A</span>
    <span data-i2="rate:2">B</span>
    <span data-i2="rate:1">C</span>
</div>
.fromCssClass {
    font-size:10px;
    opacity:0.7;
    color:#888888;
}
.toCssClass {
    font-size:30px;
    opacity:1;
    color:#000000;
}
i2.emph();