Messing with calc

dabblet.css

/**
 * Messing with calc
 */

body {
	margin: 0;

}

div {
	background-color: #353535;
	color: #fff;
	overflow: hidden;
	padding: 1em;
	text-align:center;
}

p {
	background-color: purple;
	border: 4px solid #ccc;
	display: inline-block;
	float: left;
	margin-left: 0.5%;
	width: -webkit-calc(33.3% - 14px);
}

p:first-child {
	margin-left: 0;
}

dabblet.html

<div>
	<p>Testing calc</p>
	<p>Testing calc</p>
	<p>Testing calc</p>
</div>

settings.json

{"view":"split","fontsize":"100","seethrough":"","prefixfree":"1","page":"css"}