In the HEX value it would be:
In the HSLA value it would be:
With the RGBa value you can change the opacity of a color so rgb(24, 244, 0) with an opacity of 50% would look like:
To add a background colour with the colour values above you will need to add the background-color: ; attribute inside of the open brace and close brace. Then you can add your colour value between the colon and semi-colon.
As well as being able to customize the background colour of a HTML element, you can also change the colours of borders, text, shadows etc.