CSS for Special Heading with faded background behind Title and SubHeading

av_heading
Can you tell me tell me how to make the background of the av_heading a lighter opacity while retaining the FULL opacity of the text?
I’ve tried multiple, multiple things, but it’s just not working.
It’s a basic av_heading with subheading, per below.
Can you tell me what the CSS might be to put a light semi-opaque background behind the title and subheading?

Thanks for any help.

[av_heading heading='Hi there! Covid wants to be <em><u>YOUR</u></em> hitchhiker!' tag='h2' link='' link_target='' style='blockquote modern-quote' size='' subheading_active='subheading_below' subheading_size='' margin='' padding='10' color='' custom_font='' custom_class='buggy-headline' id='' admin_preview_bg='' av-desktop-hide='' av-medium-hide='' av-small-hide='' av-mini-hide='' av-medium-font-size-title='' av-small-font-size-title='' av-mini-font-size-title='' av-medium-font-size='' av-small-font-size='' av-mini-font-size='' av_uid='av-a0owr']
Tired of cleaning your car -- and not being sure it IS clean and safe for your family and business?

Let us help you get your car clean, sanitized and safe-- quick and easy.
[/av_heading]