Remove sidebar in NGO Lite Theme

Hi,

I need help how to programme our website to ensure it spreads across 100% of the screen on the desktop and mobile devices.

Challenge: I programmed the CSS Additional at 150% width for the content area to cover the empty sidebar after trying to remove it. However, it also uses 150% for mobile devises and is consequently too wide even though I tried to adjust it to 100% for mobile decides only (see below).

Can someone assist to
– either adjust width to desktop and mobile screen respectively
– or removing the entire sidebar, not only content
– added code in CSS additional to spread content across screen (@mobile code doesn’t seem to work)
What I did:
– downloaded NGO Lite theme
– tried to remove sidebar by editing code for index.php, page.php, single.php, archive.php, home.php (deleted <?php get_sidebar(); ?>)
– .content-area {
width: 150%;
margin: 0px;
border: 0px;
padding: 0px;
}
@media only screen
.content-area {
width: 100%;
margin: 0px;
border: 0px;
padding: 0px;

.content-area .site {
margin:0px;
}
}

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