Inside-article Border

Hello,

I have used the Marketer theme, and now I have the following problem.
When I use content layout for this layout, each article still has a small thin border.

The CSS code says:

.inside-article, .sidebar .widget, .comments-area {
    border: 1px solid rgba(232, 234, 237, 1);
    box-shadow: 0 0 10px rgba(232, 234, 237, 0.5);
}

So I have tried to use the following code with Simple CSS.

.inside-article {
      border: 0px solid #DDD !important;
}

Or:

.inside-article {
      border: none !important;
}

Unfortunately without success. I would like to remove the border or just have a border under each article. Just like it is on the start page of woorkup.

.inside-article, .sidebar .widget, .comments-area {
    border: 1px solid rgba(232, 234, 237, 1);
    box-shadow: 0 0 10px rgba(232, 234, 237, 0.5);
}