Hello,
We have customised the theme on osTicketAwesome (with the CSS).
On 16:9 screen, we don't have any problem.
But, on 21:9 screen, we have this :

For information, the logo and text in footer are an image inserted as background image in the "osticket" div and the "ostawesome" div have property display:none.
Information for OsTicket installation :
osTicket v1.14.2 // osTicket-1.14.2-Awesome-103
PHP 7.2.31-1+ubuntu16.04.1+deb.sury.org+1 // MySQL 10.0.38 // Apache/2.4.18 (Ubuntu) web server
That definitely is not happening on this end.

It is probably something in your custom CSS. If you turn it off I think this issue will go away.

However, you can add this to the bottom of your CSS to override whatever you have that is causing this issue:
#content,
#open-or-check,
#check-ticket,
#complianceouter,
#compliance,
#more-options,
#information,
#footer {
background-image: none !important;
}
Let me know if this helps so I can mark this as resolved.
Hello, I have tried the two solutions but I always the same problem :
I would like the blue background stop at the bottom of the footer logos (it's the real problem).
And I don't have this on 16:9 or mobile screen.
Thanks.
I'm sorry, but I am really struggling to understand how your last screenshot relates to the first one you posted.
Did the problem on your Client homepage go away after disabling your Custom CSS?
Regarding the blue footer that seems to be really tall, in reality it is not. I designed the background color of the entire page (the <html> tag) to be the same color as the footer.
To illustrate, if you add the following to your Custom CSS...
html {
background: initial;
`}
...you'll see that the footer is actually only 80px tall.

So I really doubt your problem is with the footer. But I honestly don't understand what your problem is.
If you want me to take a look, you can post a link to your support system here or email it to me: info@osticketawesome.com
I have another screen more accurate where you can see the problem (with the css added) :
It's the same (but in blue) if I deactivate the custom css.
I think it's linked to the resolution of the screen (the height of the screen is superior to the height of the website or something like that).