Change default Google font URL in The7 theme

functions.php

function my_dt_make_web_font_uri( $font, $effect = '' ) {
	if ( !$font ) {
		return false;
	}

	// add web font effect
	if ( function_exists('dt_get_web_fonts_effects') ) {

		if ( array_key_exists( $effect, dt_get_web_fonts_effects() ) ) {
			$effect = '&effect=' . esc_attr( $effect );
		} else {
			$effect = '';
		}

	} else {
		$effect = '';
	}
	//Here you can set own google mirror
	return '//fonts.useso.com/css?family=' . str_replace( ' ', '+', $font ) . $effect;
}

/**
 * Web fonts override.
 *
 */
function presscore_enqueue_web_fonts() {
	$fonts = array();
	$options = _optionsframework_get_clean_options();
	foreach ( $options as $option ) {
		if ( 'web_fonts' === $option['type'] ) {
			// Replace & coz in db value sanitized with esc_attr().
			$fonts[] = str_replace( '&', '&', of_get_option( $option['id'] ) );
		}
	}

	$fonts_compressor = new Presscore_Web_Fonts_Compressor();
	$compressed_fonts = $fonts_compressor->compress_fonts( presscore_filter_web_fonts( $fonts ) );

	wp_enqueue_style( 'dt-web-fonts', my_dt_make_web_font_uri( $compressed_fonts ) );
}