How To Edit The Sidebar Box Color?

Hi there,

are you using this plugin:

https://en-gb.wordpress.org/plugins/easy-table-of-contents/

If so it has a lot of customization controls in the plugin settings.

Yes i am using that plugin, but i am trying to change something else. It's the widget that's getting all colorful and stuff, so no matter what i move to it, it changes the color.

Aah ok.
In Customizer > Additional CSS ... delete this CSS:

.sidebar .widget:first-child {
    background-image: linear-gradient( 145deg, rgb(164,218,216) 0%, rgb(228,243,242) 100%);
}