Phoenix2k/inline_stylesheet.php

## inline_stylesheet.php
<?php
/**
 * Prints out entire stylesheet in the <head> section of the site.
 * Supports replacing relative URLs
 */
add_action( 'wp_head', function() {

	$stylesheet = get_stylesheet_directory() . '/style.min.css';
	if ( ! file_exists( $stylesheet ) ) return echo '<!--404-CSS-->';
	$stylesheet = file_get_contents( $stylesheet );

	$relative_urls = array(
		'fonts/' => get_stylesheet_directory_uri() . '/fonts/',
		'img/'   => get_stylesheet_directory_uri() . '/img/',
		'js/'    => get_stylesheet_directory_uri() . '/js/'
	);

	foreach ( $relative_urls as $relative_url => $theme_url ) {
		$stylesheet = str_replace( 'url(' . $relative_url, 'url(' . $theme_url, $stylesheet );
	}

	printf( "\n" . '<style>%s</style>' . "\n", $stylesheet );
} );
	<?php
	/**
	* Prints out entire stylesheet in the <head> section of the site.
	* Supports replacing relative URLs
	*/
	add_action( 'wp_head', function() {

	$stylesheet = get_stylesheet_directory() . '/style.min.css';
	if ( ! file_exists( $stylesheet ) ) return echo '<!--404-CSS-->';
	$stylesheet = file_get_contents( $stylesheet );

	$relative_urls = array(
	'fonts/' => get_stylesheet_directory_uri() . '/fonts/',
	'img/' => get_stylesheet_directory_uri() . '/img/',
	'js/' => get_stylesheet_directory_uri() . '/js/'
	);

	foreach ( $relative_urls as $relative_url => $theme_url ) {
	$stylesheet = str_replace( 'url(' . $relative_url, 'url(' . $theme_url, $stylesheet );
	}

	printf( "\n" . '<style>%s</style>' . "\n", $stylesheet );
	} );