Widget Title change background Colour by CSS

Not sure if this is possible

I have the main website using another THEME -- (( but can't update the theme as there is a Text Quotation page with back end coding that won't upgrade your new theme - - stops working - long story as I had a 3rd party develop this part of the site and they did not mention that the WP theme could never be updated ??? ))

however as a work around -- I added the Decal SHOP using your theme and WooCommerce to a sub domain and am doing some colour changes to try and match the other theme --- its not quite there but is sort of similar...

what I need:
I was wondering if it would be possible to isolate the Widget Title background Colour CSS to have it own independant background colour ?

why?
if you look at the main site you can see the widgets have a title with a coloured background

https://www.glassvinylgraphics.com.au/

and then when you look at the SHOP site - the Widget is the same colour but the Title is not

https://shop.glassvinylgraphics.com.au/product/shamrock-irl-vinyl-decal/

AND finally

there is a arrow as a BULLET point - can this be done too OR am I asking too much ?

just throwing it out there as it a toss up between FLAT FLAT web site layout ( which I like for a full width screen design ) but this site harps back to the full colour design layout with a background image and banner at the top --