What is this variable kind of thing in css?

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I just discovered something in css, forwhat I can not find any explanations in google. I'm pretty bad with css, so I hope you can explain this to me.

outline-color: Highlight

I mean the 'Highlight'. My struggle is, I never declared this in any way and I never heard of it neither. If I use it, it is just a blueish color.

Is this any kind of system-specific variable? Are there any other things like this?

Highlight is indeed a system color keyword, documented in section 18.2 of CSS2 and section 4.5.1 of css-color-3. It does vary depending on the OS or platform displaying this color. It is not the same thing as a custom property (or CSS variable) — custom property names begin with -- and are referenced using var(). It's much more akin to things like red, green and blue, also predefined colors, but not system colors.

The description is very brief but should give you a rough idea of what it represents (assuming the name "Highlight" doesn't already!):

Highlight Item(s) selected in a control.

In any case, system colors are deprecated and should not be used in public sites.

Everything you need to know about CSS Variables, Variables in CSS should be declared within a CSS selector that defines its scope. For a global scope you can use either the :root or the body selector. The variable​  So, Can We Use CSS Variables Yet? I think the time is now. That IE11 support is not going to get any better, and we know from previous versions of Windows that it takes a long time for some people to upgrade. But the support across modern browsers is great which means we should be looking to CSS Variables and experimenting with the possibilities.

Browsers have predefined color, the usual are red, yellow, coral or something like this, but they also have colornames for colors, which are part of the design scheme of the specific browser. For example buttonface is the greyish color of buttons in Chrome. So to keep safe always use the usual colors, because the OS/Browser specific ones could always change.

Learn CSS Variables in 5 minutes, So, variables declared in this way are kind of scoped to the global scope. Got that​? With native CSS variables, things are a little different. A variable is a container for a value, like a number we might use in a sum, or a string that we might use as part of a sentence. But one special thing about variables is that their contained values can change.

Highlight is a predefined color in css which the browser will recognise, much like your standard red, blue etc....

If you play around in devtools on chrome or another inspector you can see all these colors.

Hope that helps :)

symbols, How to define and use CSS Variables (also known as custom properties). Let me start with something you may already be familiar with: using  - [Instructor] CSS is an evolving language, and to stand out here in an interview, it's good to show that you're keeping up with some of the latest features. And one of the most useful features upcoming in CSS is variables. So let's take a look at how they work, and how we can use them in an existing CSS file.

If you're talking about the selection color, here is the css code:

::-moz-selection {
  background: #ccc;
::selection {
  background: #ccc;

Note that the moz prefix is for firefox. You can replace #ccc with your color. However if you're talking about using variables in css, try sass

CSS Variables - var() Function, Variables are one of the major reasons CSS preprocessors exist at all. The ability to set a Duration: 56:58 Posted: Oct 25, 2016 The strategy of using CSS Variables to drive the switching of layouts and interactions that we covered in the first post in this series comes with one major caveat: it only works with numeric values — lengths, percentages, angles, durations, frequencies, unit-less number values and so on.

CSS Variables explained with 5 examples, Highlight is indeed a system color keyword, documented in section 18.2 of CSS2 and section 4.5.1 of css-color-3. It does vary depending on the  This kind of thing is what makes code hard to read. And remember, you should write your code thinking of the moron who comes after you that is going to have to maintain it. And that moron is probably you. As my own favorite moron, I’ve been making a conscious effort lately to avoid writing if statements in my JavaScript. I don’t always

What is the difference between CSS variables and preprocessor , Not quite, mainly because CSS variables are something different from preprocessor variables. The differences spring from the fact that CSS  Variable declaration All the variables must be declared before their use. It does two things: (a) Tell the compiler what the variable name is. (b) Specify what type of data that a variable will hold. Syntax of variable declaration: data_type variable_name; Example of variable declaration: int i,j,k; char ch;

What is this variable kind of thing in css?, CSS variables, more accurately known as CSS custom properties, are landing in Chrome all the things, but on a large enough project this could easily get dangerous. This means custom properties have the potential to unlock all kinds of  The issue of doing (c) is that we basically make it impossible to create variables to images if you own a theme.css but do no know on which site(s) your theme will be installed on (but you know the images will be in the same folder as your css file).

  • Pretty sure because it doesnt recognise the word Highlight that its setting it to the default blue
  • That is just a keyword, one of the now deprecated "system colors". See, e.g., quackit.com/css/color/values/css_system_colors.cfm
  • And they are deprecated.