ikaring

Hi.
You can add any shortcode in your theme functions.php.
This is very basic one to return ‘Hi!’ with p tag.
It can be called by [std].

function std_func( $atts ) {
	return "<p>Hi!</p>";
}
add_shortcode( 'std', 'std_func' );

It seems you have set additional css:

.module.widget-handle i {
  display: none;
}

Try removing it.

The layout in that page uses Masonry, and I suppose it does not set to trigger re-location of items when window resize.
Customizer only changes window size and does not reload page, so Masonry wont be triggered. Or it might be a trigger timing, because customiser animates window size change.

Anyway.
It should be OK when viewed with real device, since it will be triggerd when page loads.

Hi.
I believe your page url is wrong.

OK.
Pls try below code instead.
Since function woocommerce_product_loop_start now has filter hook, it would be better use it.
Note this fix might affect other product loop output.

add_filter( 'woocommerce_product_loop_start', 'my_product_loop_start' );
function my_product_loop_start( $echo = true ) {
  $loop_start = '<ul class="grid product-list clearfix desktop-columns-4 tablet-columns-2 mobile-columns-1">';
  if ( $echo ) {
    echo $loop_start;
  } else {
    return $loop_start;
  }
}

Have you resolved them? I dont see them now.

Hi.
You can fix to add css:

textarea {
  max-width: 100%;
}

Hi.
It looks ok and there are many css files loaded.
Have you resolved?

Anyway, you can just replace current theme files with your backup theme files for restoring/downgrading.