Style the post date on the Genesis post info line

functions.php

<?php

add_filter( 'genesis_post_date_shortcode', 'child_post_date_shortcode', 10, 2 );
/**
 * Customize Post Date format and add extra markup for CSS targeting.
 *
 * @author Gary Jones
 * @link   http://code.garyjones.co.uk/style-post-info/
 *
 * @param string $output Current HTML markup.
 * @param array  $atts   Attributes.
 *
 * @return string HTML markup.
 */
function child_post_date_shortcode( $output, $atts ) {

	return sprintf(
		'<span class="date time published" title="%4$s">%1$s<span class="day">%2$s</span> <span class="month">%3$s</span></span>',
		$atts['label'],
		get_the_time( 'j' ),
		get_the_time( 'M' ),
		get_the_time( 'Y-m-d\TH:i:sO' )
	);

}

style.css

.post-info {
	border-bottom: 1px solid #e1e1e1;
	font-family: Georgia, sans-serif;
	font-size: 12px;
	font-style: italic;
	margin: 0 0 5px;
	padding: 5px 0 15px 60px;
}
.post-info .time,
.post-info .time span {
	color: #fff;
	display: block;
	text-align: center;
	width: 42px;
}
.post-info .time {
	left: 10px;
	position: absolute;
	top: 10px;
}
.post-info .day {
	background: #8ab6d9;
	font-size: 26px;
	font-weight: bold;
	height: 29px;
	line-height: 1em;
}
.post-info .month {
	background: #6c8fac;
	height: 18px;
	line-height: 1.33333;
	text-transform: uppercase;
}
#content .post {
	position: relative;
}
#content .post h1 {
	margin-left: 60px;
}
#content .post h2 {
	font-size: 18px;
	margin: 10px 10px 0 60px;
}