css - I can not change the background-color value of wp: meta_value of content.xml

I can not change the background-color value of <wp: meta_value>

I'm trying to change by css the value of background-color in the class that is automatically generated by the Visual Composer called:

vc_custom_1510991353768

with this:

.vc_custom_1510991353768 {
    background-color: #006e48 !important;
}

But, my styles.css of child theme does not recognize because it is owned by , according to the code referenced below:

<wp:postmeta>
    <wp:meta_key><![CDATA[_wpb_shortcodes_custom_css]]></wp:meta_key>
    <wp:meta_value><![CDATA[.vc_custom_1510991353768{background-color: #22355b !important;}]]></wp:meta_value>
</wp:postmeta>

I already try this (Custom colors for post rows based on post meta value ), but this dont work for me.

I need help, thanks in advance

EDIT:

I got it by following this: thanks guys