Need help on how to change background color in Antimatter theme

Hello I am new to Grav. So far I like it better than WordPress and I use it as replacement of Evernote.

I like the simplicity of Antimatter, however I would like to know on how to change the background color of my posts.

You need to add some custom CSS. Create a custom.css file in user/themes/antimatter/css. Antimatter will load it automatically if found.

#body {
    background-color: black;
}

Thanks. It kinda works.
There is a white line below my blog post like these.

Image 002 Image 003

What should I do?

I think overwriting the background of '#sb-site' should create your expected result

#sb-site {
   background: #000000;
}
---

I put

#sb-site {
   background: #000000;
}

in the custom.css but it changes nothing.

Okay I just tested it myself. The normal css was overwriting the custom css. I tried it with this snipped on a fresh GRAV installation and it worked.

#body { background-color: #000000; }

body #sb-site,
body .sb-site-container {  background-color: #000000;}
---

Oh cool thank you so much. Would you mind if you tell me how can you know the class/id name (#sb-site, .sb-site-container, etc)? Is there any documentation?

Now, I need to change the font to somewhat white-ish. I will open another thread.

https://developers.google.com/web/tools/chrome-devtools/ or
https://addons.mozilla.org/de/firefox/addon/firebug/

I got the reference for #sb-site using View Source and Inspect Element in Chrome. But not for .sb-site-container.

But whatever thanks for helping. I will learn this eventually I hope.