.widget, article not found on Wordpress style.css

I am trying to find the element ".widget, article " in my style.css for my theme. What happened was it shows on developer tools, but I can't find it in the style page.

The layout is for the background, and is white by default

The web developer tools says its layout is

<article>
<header class="entry-header">...</header>
<div class="entry-content clearfix">...</div>
...

The Styles page says its in index:156 of the theme

.widget, article {
  background: #8C3737;
}

I can't find the article element or change the index.php file appropriately to make the background transparent.

Any ideas of how to echo the id for the article when it loads, or any other?