functions.php

/**
 * Add a new section class that allows for adding sectional titles to the customizer
 * @param class $wp_customize Instance of WP_Customize_Manager created when using the 'customize_register' hook
 */
add_action( 'customize_register', 'jn_section_titles_class' );
function jn_section_titles_class($wp_customize) {

	/**
	 * Extends the WP_Customize_Section for custom output
	 * @return void
	 */
	class JN_Customizer_Section_Title extends WP_Customize_Section {

		/**
		 * Render the sectional title in the customiser
		 * @access public
		 * @return void
		 */
		public function render() {
			$id = $this->id;
			$title = $this->title;
			$description = $this->description;
			?>
			<li id="accordion-section-<?php echo $id; ?>" class="accordion-sectional-title" style="">
			<?php if($title) { ?>
					<h3 class="sectional-title" tabindex="-1">
						<?php echo $title; ?>
					</h3>
				<?php } ?>
				<?php if( $description!='' ) { ?>
					<span class="description sectional-title-description"><?php echo $description; ?></span>
				<?php } ?>
			</li>
		<?php
		} // end render

	} // end extend class
}