CSS calculate using initial value

Question

is there a way in CSS to get the initial parameter of something, without using javascript, for example:

width: calc(initial-20px);

if so, ho can i retrieve the value of specific parameters, like width.initial?

SCENARIO

It's a visual studio web browser, (it doesn't support css3 by default), i whant an element to look like highlited, but i can only do it through html attributes(i wanna go the easy way). So i could just style="background-color: yellow !important;", but what if background is already yellow? So i decided that calculating the highlight color would fix be awesome ( as i know now it is impossible through css ) background-color: rgb(initial,calc(initial-50),initial) !important; something like that. So this is a scenario. Suggestions are apreciated.

Answer 1

Simply put, no it is not possible to do this with css. You also can't perform calculations like that. You can only do calculations for percentages, like Mooseman said (edit: Mooseman deleted his answer. It mentioned that you can use width: calc(100% - 40px); for example, but you can't use initial like that). for either of those things you would need to use JavaScript.

Edit: Another option for modifying width could be a margin, although that doesn't necessarily do exactly what you want. For highlighting, you could use something like this:

p {
    background-color: #FFFF00;
}
p:hover {
    background-image: linear-gradient(rgba(255, 255, 255, 0.4), rgba(255, 255, 255, 0.4));
}

<p>Example paragraph with background</p>

This way you overlay a translucent white layer on top of your background-color, making it a bit lighter. That way you can change the background colour without having to know what the original background was.

Answer 2

i think you can Use LESS.

You Can See Here: http://www.ibm.com/developerworks/opensource/library/wa-less/index.html