Why my gallery is not full-wide?

I wanted to make a gallery page like the one in demo: https://colorlib.com/unite/gallery/
I instaled jetpack, turned on tiled galleries, made new page, choose the page option without sidebar, made a gallery and set tiled mosaic. In result my gallery looks like the side bar is on the right but this space is empty. I was looking at the topics on this forum and havn’t seen anyone else having this problem.
Everything else apart from gallery is ok full-wide (text and single images).
What can be the problem? Can someone help me?
The address of my gallery is: http://szczawa.org.pl/fotografia/fotografia-slubna/magdalena-i-marian/

I have found help on another support forum.

Solution:
I installed plugin: Custom Content Width.
I set it (in media settings) for 1200px.

Then I added to the .tiled-gallery class in my css:

.tiled-gallery {
max-width: 1200px;
margin: auto !important;
}

It works :wink:

Hi @gosiaa,

Awesome great to see you got that worked.

Please advise if you have more questions.

Have a fantastic day!

Cheers,
Movin