JSFiddle - React, Tailwind, and code Playground
HTML
<div style="width: 900px; background-color: Gray;">
<div style="width: 165px; border: solid 1px yellow; float:left;">
<div style="width: 155px;">A</div>
</div>
<asp:PlaceHolder ID="phTest" runat="server" Visible="true">
<div style="width: 230px; float: left;">
<div style="width: 230px;">B</div>
</div>
</asp:PlaceHolder>
<div style="border: solid 1px green;">C</div>
</div>