Make listings area wider

 .hp-listings .hp-block .hp-grid{width:900px}

I tried the css code above but doesnt work, what is the css class for the listings , the area beside the filter form?

It has class .hp-template--listings-view-page .hp-page__content . But if you want to change its width then it is needed to change these CSS properties values flex-basis - CSS: Cascading Style Sheets | MDNand max-width - CSS: Cascading Style Sheets | MDN
It is possible to view which values of these properties it has now by using Developer Tools View and change CSS - Chrome Developers