thats why i like to see the page.
on source code this will be the easiest way to see that on first view.

to enable gzip there are a lot of options. It depends on your Internet Service Provider what options he allows you to set via php.ini or htaccess.
I often do it via htaccess file on the wordpress root (the htaccess file is a hidden file with a dot on front – so on ftp client you might not see it directly till you enable show hidden files)
there you can set a lot of other options : f.e. browser caching , etag and gzip

on apache servers i add to my htaccess file:

# Secure your wp-config
# Disallow access to important files
<FilesMatch "(^\.|wp-config\.php|xmlrpc\.php|(?<!robots)\.txt|(liesmich|readme)\.*)">
   Require all denied
</FilesMatch>

# secure htaccess-file
<files ~ "^.*\.([Hh][Tt][Aa])">
order allow,deny
deny from all
satisfy all
</files>

# Keep-Alive
<ifModule mod_headers.c>
   Header set Connection keep-alive
</ifModule>
 

# mime types
<IfModule mod_mime.c>
    AddType application/javascript          js
    AddType application/vnd.ms-fontobject   eot
    AddType application/x-font-ttf          ttf ttc
    AddType font/opentype                   otf
    AddType application/x-font-woff         woff
    AddType application/x-woff              woff
    AddType image/svg+xml                   svg svgz 
    AddEncoding gzip                        svgz
</Ifmodule>
 

# GZip Kompression
<IfModule mod_gzip.c>
 mod_gzip_on       Yes
 mod_gzip_dechunk  Yes
 mod_gzip_item_include file      \.(html?|txt|css|js|svg|php|pl)$
 mod_gzip_item_include handler   ^cgi-script$
 mod_gzip_item_include mime      ^text/.*
 mod_gzip_item_include mime      ^application/x-javascript.*
 mod_gzip_item_exclude mime      ^image/.*
 mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
</IfModule>

 
# Browsercache
<IfModule mod_expires.c>
 ExpiresActive On
 ExpiresDefault "access plus 1 month"
 ExpiresByType text/css "access plus 1 month"
 ExpiresByType text/javascript "access plus 1 month"
 ExpiresByType text/html "access plus 1 month"
 ExpiresByType application/javascript "access plus 1 month"
 ExpiresByType application/x-javascript "access plus 1 month"
 ExpiresByType application/x-font-ttf "access plus 1 month"
 ExpiresByType application/x-font-woff "access plus 1 month"
 ExpiresByType application/x-woff "access plus 1 month"
 ExpiresByType application/xhtml-xml "access plus 600 seconds"
 ExpiresByType image/gif "access plus 1 month"
 ExpiresByType image/jpeg "access plus 1 month"
 ExpiresByType image/svg+xml "access plus 1 year"
 ExpiresByType image/svg "access plus 1 year“
 ExpiresByType image/png "access plus 1 month"
 ExpiresByType image/x-icon "access plus 1 month"
</IfModule>

 
# Deflate by FileType
<IfModule mod_deflate.c>
 AddOutputFilterByType DEFLATE text/plain
 AddOutputFilterByType DEFLATE text/html
 AddOutputFilterByType DEFLATE text/xml
 AddOutputFilterByType DEFLATE text/css
 AddOutputFilterByType DEFLATE text/javascript
 AddOutputFilterByType DEFLATE image/svg+xml
 AddOutputFilterByType DEFLATE application/javascript
 AddOutputFilterByType DEFLATE application/xml
 AddOutputFilterByType DEFLATE application/xhtml+xml
 AddOutputFilterByType DEFLATE application/rss+xml
 AddOutputFilterByType DEFLATE application/atom_xml
 AddOutputFilterByType DEFLATE application/x-woff
 AddOutputFilterByType DEFLATE application/x-font-ttf
 AddOutputFilterByType DEFLATE application/x-font-woff
 AddOutputFilterByType DEFLATE application/javascript
 AddOutputFilterByType DEFLATE application/x-javascript
 AddOutputFilterByType DEFLATE application/x-shockwave-flash
</IfModule>
 
# ETag
Header unset ETag
FileETag None

do this to your functions.php of your child-theme and all links got that addendum:

function add_to_youtube_videos(){
if(is_page(21397)){
?>
<script>
(function($){
	$('.lightbox-added[href*="www.you"]').each(function() {
	   var $this = $(this);       
	   var _href = $this.attr("href"); 
	   $this.attr("href", _href + '?enablejsapi=1&ecver=2&autoplay=1&cc_load_policy=1&playsinline=1&rel=0&showinfo=0&color=white&iv_load_policy=3');
	});  
})(jQuery);
</script>
<?php
}
}
add_action('wp_footer', 'add_to_youtube_videos');

gut – aber denke mal darüber nach ob du nicht diesen Rattenschwanz da immer dran basteln solltest.
Denn wenn du das Video jetzt startest, und dann pausierst, dann siehst Du was ich mit Werbung meine ( das wird mit dem ecver=2 verhindert.) und am ende die related Videos mit dem rel=0 etc. pp.
Ausserdem ist die Nocookie Variante jetzt ohnehin besser wegen der DSGVO ( GDPR )

if you gave the class to the text block than it is at the same div
all classes which are at the same div are not separated by space:

this:

will definitly go to (without spaces on css rules) !
div.avia_textblock.my_custom_class h2
there is on html source a space between (because the dots are gone)

the space comes to the h2 because it is a child of avia_text_block

please show me the link to see something that is not possible

it is hard to help without a link
but first solution was to try get rid of doubled semicolons
second : add rule for firefox and modern browsers – you have all without :

#contactform ::placeholder { 
    color: #fff !important;
    opacity: 1; 
}

the webkit rule seems to be obsolete since Safari 10

this is what is enough for modern browser:

::placeholder { /* Chrome, Firefox, Opera, Safari 10.1+ */
    color: white !important;
    opacity: 1; /* Firefox */
}
:-ms-input-placeholder { /* Internet Explorer 10-11 */
    color: white !important;
}
::-ms-input-placeholder { /* Microsoft Edge */
    color: white !important;
}

this seems to be a good plugin – even the wordpress official sites link to it:
https://de.wordpress.org/plugins/force-strong-passwords/

yes and where on my thread is a space between those classes? https://kriesi.at/support/topic/font-css-class-not-working/#post-956107

.avia_textblock.my_custom_class h2 { font-family: "proxima_nova_rgbold"; font-size: 100px; letter-spacing: normal; text-transform: none !important; }

and what does this mean: Textblock class id = my_custom_class
is it a class or an id ;)

if you haven’t changed link it makes me wonder that it has opend before in a lightbox
add behind your youtube link add ?iframe=true f.e.: https://youtu.be/YEmI2MDpasE?iframe=true
if you have more options like me it is with &iframe=true
i would prefer links with many options to avoid related videos at the end ; related videos on pause etc.
the nocookie is nice to have because of new GDPR (DSGVO on german spoken countries)

https://www.youtube-nocookie.com/embed/<strong>ID</strong>?enablejsapi=1&ecver=2&cc_load_policy=1&playsinline=1&rel=0&showinfo=0&color=white&iv_load_policy=3&iframe=true

on cf7 you have that options directly preconfigured: https://contactform7.com/custom-layout-for-checkboxes-and-radio-buttons/
you only have to style it a bit

see edited content above

to where should the shadow go ? outside the browser – only on top and bottom ?
you can give it an inset shadow:

.color-section {
    box-shadow: 0px 0px 35px black inset;
}

or if you like the slider above:

#full_slider_1 {
    box-shadow: 0px 10px 15px -10px #000;
}

and for that it would be nice if you are not minifiying the css or js – because if there was an error we can search til the end of time.

But you have the possibility to set elsewhere on that enfold installation a lightbox image.?
I don not see that the avia-snippet-lightbox.js was activated.

please read the edited answer before