Sidebar area background

Hello,

?Please try to add the below CSS code from the Appearance > Customize > Custom CSS, and check.

.widget-area.sidebar-primary {
    background-color: #2a355e;
}

PS- Change the color code according to need.

If not resolved with the above, kindly share that page URL where you want to change.

Thank you @abhikr781
I did not describe the question correctly.
What i am looking for is the entire vertical area where the sidebar stays – the area between page title bottom border to the footer top border, not just the sidebar area.
The CSS code you offered is for the sidebar only, the page looks ugly while i set background for sidebar only…

Hello,

Please try the below CSS code and check.

.content-left-sidebar .widget-area {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    overflow: hidden;
    z-index: -1;
    background-color: #4641fc;
}