Edin Theme: Inefficent use of space (loads of white space)

Greetings!
I’ve been editing a website over the past few days and I’m really loving the edin theme. However I did notice when creating pages that the use of white space in pages is really inefficient.
If you look at the page (https://www.armatura-uz.si/education-facilites/) you can see a lot of space to the left and the right, like I’d like the text to use the psace here aswell: https://i.imgur.com/VlETWiL.png
I tried eliminating the extension (column shortcodes) to see if tht was causing it but it didn’t seem to work.
I did look trough the forums here and saw some other people with whitespace issues but those were mostly header related so I couldn’t help myself with that.

If possible I would also like to reduce the height of the featured image on secondary pages.

I tried this code that I found but it didn’t seem to change anything:

@media screen and (min-width: 1230px) {
    .content-area {
        width: 540px;
    }
    
    .widget-area {
        width: 300px;
    }
}

Thank you in advance ??

The page I need help with: [log in to see the link]