HamSter

audio::-webkit-media-controls-panel
audio::-webkit-media-controls-mute-button
audio::-webkit-media-controls-play-button
audio::-webkit-media-controls-timeline-container
audio::-webkit-media-controls-current-time-display
audio::-webkit-media-controls-time-remaining-display
audio::-webkit-media-controls-timeline
audio::-webkit-media-controls-volume-slider-container
audio::-webkit-media-controls-volume-slider
audio::-webkit-media-controls-seek-back-button
audio::-webkit-media-controls-seek-forward-button
audio::-webkit-media-controls-fullscreen-button
audio::-webkit-media-controls-rewind-button
audio::-webkit-media-controls-return-to-realtime-button
audio::-webkit-media-controls-toggle-closed-captions-button

var el = document.getElementById('col');
if (el) {
  el.classList.add('some-class');
}

var el = document.getElementById('col');
if (el) {
  var otherEl = document.getElementById('other-id');
  if (otherEl) {
    otherEl.classList.add('some-class');
  }
}

jQuery(document).ready(function() { 	
	jQuery( "#idForm" ).submit(function( event ) {		
		yaCounter1234567.reachGoal('Feedback');		
		console.log("target reached!");	
	});	
});

@font-face
    font-family: "RobotoRegular"
    src : url("../fonts/RobotoRegular/RobotoRegular.ttf")

$wp_customize->selective_refresh->add_partial('testtheme_logo', array(
        'selector' => '.navbar-brand',
        'render_callback' => function() {
            $img = get_theme_mod('testtheme_logo');
            if (is_numeric($img)):
                ?>
                <img src="<?php echo wp_get_attachment_url($img); ?>" alt="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>">
            <?php
            endif;
        },
    ));

например, табы, аккордеон, слайдеры на чистом CSS при помощи разнообразных селекторов