<?php 
function bsquare_fonts() {
wp_enqueue_style( 'google_fonts', google_fonts(), null, null, 'all');
}
add_action( 'wp_enqueue_scripts', 'bsquare_fonts' );

function google_fonts() {
	$query_args = array(
		'family' => 'Rubik:300,400,500,700,900',
		'subset' => 'latin,latin-ext',
	);
	wp_register_style( 'google_fonts', add_query_arg( $query_args, "//fonts.googleapis.com/css" ), array(), null );
}