Load a custom style sheet on your site using the Genesis Framework.

functions.php

<?php
//* Do NOT include the opening php tag

//* Load custom style sheet
add_action( 'wp_enqueue_scripts', 'custom_load_custom_style_sheet' );
function custom_load_custom_style_sheet() {
	wp_enqueue_style( 'custom-stylesheet', CHILD_URL . '/custom.css', array(), PARENT_THEME_VERSION );
}

//* Replace default style sheet
add_filter( 'stylesheet_uri', 'custom_replace_default_style_sheet', 10, 2 );
function custom_replace_default_style_sheet() {
	return CHILD_URL . '/custom.css';
}