JSFiddle - React, Tailwind, and code Playground

HTML

<div id="maincontentcontainer">
		<div id="maincontent">
			<div class="section group">
				<div class="col" id="callout1">
					Background should be green
				</div>
				<div class="col" id="callout2">
					Background should be lighter green
				</div>
				<div class="col span_1_of_3" id="callout3">
					Background should be lighter green
				</div>
			</div>
		</div>
	</div>

CSS

#maincontent .col {
		background: #ccc;
		background: rgba(204, 204, 204, 0.85);
	}

    #callout1	{
		background-color: #00B300!important;
		text-align:center;
    margin-bottom: 10px;
	}
	#callout2	{
		background-color: #00CC00!important;
		text-align:center;
    margin-bottom: 10px;
	}
     #callout3	{
		background-color: #00E600!important;
		text-align:center;
    margin-bottom: 10px;
	}