Fluid column layout with fixed pixel margins between them.

dabblet.css

/**
 * Fluid column layout with fixed pixel margins between them.
 */

.container {
	width:50%;
	height:10em;
	padding-left:20px
}

.box {
	height:100%;
	width:33.33%;
	float:left;
}

.first {
	margin-left:-20px;
	margin-right:10px;
	background-color:hsla(20, 80%, 55%, 1);
}

.second {
	margin-right:10px;
	background-color:hsla(140, 80%, 55%, 1);
}

.last {
	background-color:hsla(260, 80%, 55%, 1);
}

dabblet.html

<div class="container">
	<div class="box first">Column 1</div>
	<div class="box second">Column 2</div>
	<div class="box last">Column 3</div>
</div>

settings.json

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