Customizer Not loading: sanitize-functions.php Line 102 & 123

@nicolej: I will need to check your admin settings so that I can look into the issue you are having. For that I will need your WP admin credentials. I will contact you shortly by email.

Kind Regards,
Skandha

@nicolej: Hello Nicole,
I have fixed the issue with the customizer on your site. Can you please login to your site and check if the issue is resolved?

Kind Regards,
Skandha

@nicolej: No you wont need to take care of anything in the future. There were few warnings in one of the function due to which the customizer was not working. That has been fixed. 🙂

Kind Regards,
Skandha

@nicolej: Go to => Appearance => Customize => Additional CSS and add the following CSS Code.

.site-description {
	font-size:30px;
}

You can change the font size according to your requirement.
Let me know if this works out!
Kind Regards,
Skandha

@nicolej: Let me know on which specific pages you want the subheading to be displayed.

To change the height of the Header Image
Go to => Appearance => Customize => Additional CSS and add the following CSS Code.

.custom-header-content {
	padding:100px 98px 500px; 
}

You can change the padding to adjust the height of the header image.

To have different header images per page.
Go to => Dashboard => Edit a Post/page => Set a featured image.

Now,
Go to => Appearance => Customize => Header Media => Enable on Entire Site, Page/Post Featured Image

Let me know if this works out!
Kind Regards,
Skandha

@nicolej: Go to => Appearance => Customize => Additional CSS and add the following CSS Code.

body:not(.home):not(.page-id-162):not(.page-id-379):not(.page-id-409):not(.page-id-312):not(.page-id-304):not(.page-id-315):not(.page-id-296) .site-description {
	display:none;
}

This will display the site description only on your homepage, Ernährungstraining page and the sub items of Ernährungstraining.

Let me know if this is what you want!
Kind Regards,
Skandha