I was wondering if anyone would be willing to be able to answer some questions about how to modify syntax highlighting.

I would like to try modifying a couple different languages syntax but just for an example for this post, I would like to focus on XML syntax.

1.) CURRENT LINE HIGHLIGHT - FOREGROUND COLOR
For example this is the line highlight
current_line=#4D4D4D;#FFFFFF;true;false
The 2nd color is for the line background highlight, but in this case does the 1st (foreground) color do anything? I thought it might apply to text but it does not appear to.

2.) CURRENT LINE HIGHLIGHT - TRANSPARENT
Does anyone know if there are any transparent color codes available. I have seen that you can add two letters/digits in front of color codes to change the transparency but have not been able to get this to work. I have also seen "translucency" in manual translucency=256;256;false;false but do not understand how this is applied. If this is possible can someone show how this can be achieved with the following example
current_line=red;cyan;true;false
I tried putting this line below this line
translucency=100;100;false;false
but it did not appear to do anything.
It says in the manual that it is for the "current line".

Reason for this is I figured out how to add a background color to tags, just had to add a second color code to the "tag=" for example "tag=red;green" but when you use a "current_line=" background highlight it covers the tag colors completely. Not important but was just curious if could make the background highlight of the line be transparent to allow the tag background colors to be slightly seen, just wanted to see how this would look.

Thank you for any information shared.