Index.cshtml

@{
    ViewBag.Title = "Index";
}

<script type="text/javascript" src="~/Scripts/Site/SiteScript.js"></script>

<h2>Index</h2>
<hr />

<style id="style">
    /*.Row1 {
        color: red
    }

    .Row2 {
        color: green
    }

    .Row3 {
        color: blue
    }*/

</style>


<div description="Task" class="col-md-3">
    <h3>Task:</h3>
    <p>
        Set row color:<br />
        Row1 - RED<br />
        Row2 - GREEN<br />
        Row3 - BLUE<br />
    </p>
</div>

<div description="Input" class="col-md-3">
    <h2>CSS</h2>
    <textarea id="User_CSS" rows="14" style="width:100%;">
    /*[placeholder] Enter your css:*/

    .Row1 {
        color: red
    }

    .Row2 {
        color: green
    }

    .Row3 {
        color: blue
    }
    </textarea>
</div>

<div id="View" description="View" class="col-md-3">
    <h2>Render page</h2>

    <div id="View_User">
        <p id="Row1" class="Row1">Row1</p>
        <p id="Row2" class="Row2">Row2</p>
        <p id="Row3" class="Row3">Row3</p>
    </div>
</div>


<div class="col-md-12">
    <button id="B">css it</button>
    <button id="V">Validate</button>
    <input id="Validate" readonly="readonly" />
</div>

<br />