Less.js
lesscss.org
Getting started | Less.js
Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. Less runs on both the server-side (with Node.js and Rhino) or client-side (modern browsers only).
Using Less.js
Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. Less runs on both the server-side (with Node.js and Rhino) or client-side (modern browsers only).
Tools
Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. Less runs on both the server-side (with Node.js and Rhino) or client-side (modern browsers only).
In-Depth Guide
Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. Less runs on both the server-side (with Node.js and Rhino) or client-side (modern browsers only).
Functions
Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. Less runs on both the server-side (with Node.js and Rhino) or client-side (modern browsers only).
Factsheet
Designed by Alexis Sellier
Developer Alexis Sellier, Dmitry Fadeyev
First appeared 2009; 17 years ago (2009)
Designed by Alexis Sellier
Developer Alexis Sellier, Dmitry Fadeyev
First appeared 2009; 17 years ago (2009)
Wikipedia
en.wikipedia.org › wiki › Less_(style_sheet_language)
Less (style sheet language) - Wikipedia
March 26, 2024 - Less (Leaner Style Sheets; sometimes stylized as LESS) is a dynamic preprocessor style sheet language that can be compiled into Cascading Style Sheets (CSS) and run on the client side or server side. Designed by Alexis Sellier, Less is influenced by Sass and has influenced the newer "SCSS" ...
Videos
06:59
Understanding LESS CSS Variables and Nesting (Part 2) - YouTube
07:38
How to Install Less CSS (Part 1) - YouTube
26:55
Less CSS Pre-Processor Tutorial - YouTube
08:40
LESS CSS Tutorial - Using Partials (Part 5) - YouTube
How to make a nice site with less CSS
Explain Like I'm Five: What is SASS and LESS?
I'll try to give a simpler explanation, since kevan pointed out that menno's was a little high-level. SASS and LESS are just like CSS except with lots of shortcuts to write things in a much shorter way that you would with just CSS. The simplest example is using a variable. You can write "$brand_color: #FF0000" at the top of your SASS file, and then later on use $brand_color exactly like you would use the hex color like #FF0000. This is most useful when you use it in several places: then if your client decides his brand color is now #00FF00, you just need to change "$brand_color: #FF0000" to "$brand_color: #00FF00" once and that's it. Otherwise you would have to track down every place you used the brand colour and change them individually. You can set more complicated things called mixins too. A common example is to define a mixin called button, which you would use whenever you want to define a button. Mixins are very powerful because they can be modified by parameters. This means that if you realise that the CSS you wrote for two different buttons is identitical apart from some widths, because one button is bigger than the other, you could write a mixin that takes this number as an argument, and then you would not need to repeat yourself. Nesting is really nice because it means you write less. It's hard to explain, just look at the example on the SASS homepage . Because these are all "shorthands" for longer CSS, you need to first turn your SASS file into an actual CSS file, which just consists of expanding your SASS shortcuts into real CSS. For example whenever it encounters @text_color, it replaces it with #FF0000. This is called the compilation step; it is a program on your computer that you need to run, which outputs your CSS file. More on reddit.com
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July 8, 2013css selectors - What does "&" do in LESS CSS? - Stack Overflow
Compiling that to CSS will result in a rule with the selector · Copy.controls-container .flex-control-nav li a.flex-active ... Sign up to request clarification or add additional context in comments. ... So I guess the question is, why wouldn't you just do li a .flex-active? 2013-01-08T14:10:05.663Z+00:00 ... @Jared: It's li a.flex-active without the space after a. Without the & the space will be inserted (which is how nesting works in LESS... More on stackoverflow.com
html - What is a Less file? - Stack Overflow
I've started working newly on the React library. In the entire codebase that I've to work upon, I see *.less files which contain classes related to styles just as we used to have in CSS files for H... More on stackoverflow.com
Use LESS to make CSS development suck less (part III)
Not to mention the use of // as comments. Woot!
More on reddit.com 14
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May 24, 2011GitHub
github.com › less › less.js
GitHub - less/less.js: Less. The dynamic stylesheet language.
Less. The dynamic stylesheet language. Contribute to less/less.js development by creating an account on GitHub.
Starred by 17.1K users
Forked by 3.4K users
Languages JavaScript 63.7% | Less 25.6% | CSS 10.3% | JavaScript 63.7% | Less 25.6% | CSS 10.3%
GeeksforGeeks
geeksforgeeks.org › css › css-preprocessor-less
CSS Preprocessor LESS - GeeksforGeeks
January 9, 2025 - LESS (Leaner Style Sheets) is a CSS preprocessor that extends CSS with dynamic behavior, including variables, nesting, mixins, and mathematical operations, all while maintaining compatibility with standard CSS.
Gantry
docs.gantry.org › gantry4 › advanced › less-css
LESS CSS | Gantry Documentation
Any CSS file that is required to be standalone, for purposes of template parameters (such as loading Fusion Menu instead of SplitMenu) will be independent of the main /templates/[TEMPLATE]/css-compiled/[OUTPUT_CSSFILE] file. All LESS files associated with the template are located in the /wp-content/themes/[TEMPLATE]/less/ directory.
IONOS
ionos.com › digital guide › websites › web development › less css: tutorial
Less CSS Tutorial - IONOS
July 13, 2023 - Less (Leaner Style Sheets) is a reverse-compatible language extension or preprocessor for the stylesheet language CSS. This means that any CSS code is also automatically a valid Less code (but this is not true in the other direction).
Medium
medium.com › @astermanuelg › doing-more-with-less-an-introduction-to-a-css-pre-processor-b431fb16ce6
Doing more with LESS, an introduction to a CSS Pre-Processor | by Manuel Grullon | Medium
July 30, 2018 - A CSS pre processor is basically a language that let’s you write CSS in a manner that reflects other languages you may already be working in. The two most popular CSS pre processors are LESS (JS based) and SASS (Ruby based). They allow you to write CSS in new ways, ways that are more declarative and give you access to things like functions and variables.
DEV Community
dev.to › flippedcoding › the-differences-between-css-less--sass-5a74
The Differences Between CSS, LESS, & SASS - DEV Community
August 26, 2019 - That makes it easier to maintain and update you styles without doing a lot of digging to find out why that image is three extra pixels to the right. LESS stands for Leaner Style Sheets.
Medium
medium.com › matts-lambda-minutes › matts-lambda-minute-less-is-more-a-starter-s-guide-to-less-and-css-preprocessing-41b0ddd16eb7
LESS is more? A Starter’s Guide to LESS and CSS Preprocessing.
December 5, 2018 - The way it works is we write our code using a preprocessor language (Less, Sass, SCSS, Stylus), it’s then compiled via javascript(in Less that’s through Node.js) and then output into a CSS file that’s read by our HTML.
Reddit
reddit.com › r/css › explain like i'm five: what is sass and less?
r/css on Reddit: Explain Like I'm Five: What is SASS and LESS?
July 8, 2013 -
Something to do with css but that's as far as I am at this point in time.
Top answer 1 of 4
13
I'll try to give a simpler explanation, since kevan pointed out that menno's was a little high-level. SASS and LESS are just like CSS except with lots of shortcuts to write things in a much shorter way that you would with just CSS. The simplest example is using a variable. You can write "$brand_color: #FF0000" at the top of your SASS file, and then later on use $brand_color exactly like you would use the hex color like #FF0000. This is most useful when you use it in several places: then if your client decides his brand color is now #00FF00, you just need to change "$brand_color: #FF0000" to "$brand_color: #00FF00" once and that's it. Otherwise you would have to track down every place you used the brand colour and change them individually. You can set more complicated things called mixins too. A common example is to define a mixin called button, which you would use whenever you want to define a button. Mixins are very powerful because they can be modified by parameters. This means that if you realise that the CSS you wrote for two different buttons is identitical apart from some widths, because one button is bigger than the other, you could write a mixin that takes this number as an argument, and then you would not need to repeat yourself. Nesting is really nice because it means you write less. It's hard to explain, just look at the example on the SASS homepage . Because these are all "shorthands" for longer CSS, you need to first turn your SASS file into an actual CSS file, which just consists of expanding your SASS shortcuts into real CSS. For example whenever it encounters @text_color, it replaces it with #FF0000. This is called the compilation step; it is a program on your computer that you need to run, which outputs your CSS file.
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They are both languages that extend the standard CSS syntax (although differently) with some really handy constructs. There's nothing you can do with LESS or SASS that you can't with CSS since it all boils down to CSS anyway, but it makes it easier and more convenient to express certain things. LESS can be run in the browser with JavaScript. This prevents the need to recompile all the LESS files when one is changed but it also impacts performance so it's not recommended in a live setting. http://lesscss.org/ SASS is fully precompiled. http://sass-lang.com/
Nice
expert-help.nice.com › site administrative configurations › branding › extras
LESS style sheet language - Expert Success Center
February 26, 2024 - This article provides an overview of the Less language, its main features and how it extends your CSS.
CSS-Tricks
css-tricks.com › sass-vs-less
Sass vs. Less | CSS-Tricks
January 10, 2020 - Not only is it invaluable in helping to further my understanding of different syntaxes, but it makes working on others projects easier when I already know the syntax because I took the initiative to learn it. This applies to all my development tools, not just css pre-processors. ... I’ve been using SASS (+Compass) for while (2 months) – it’s GREAT! ... It does seem like LESS is winning the popularity contest…
Top answer 1 of 3
27
I know you can do something like
&:hover, but not familiar with showing a class right after it?
It's the same logic here: chaining the inner selector to whatever is represented by the outer selector. Pseudo-classes like :hover and classes like .flex-active behave the same with &.
Compiling that to CSS will result in a rule with the selector
Copy.controls-container .flex-control-nav li a.flex-active
2 of 3
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The & appends the parent nesting structure where ever the & may occur. So as others have noted, putting the & in your example takes the full nested string of .controls-container .flex-control-nav li a and replaces the & in your code to (in this case) cause the .flex-active class to be conjoined to the a tag...
Copy.controls-container .flex-control-nav li a.flex-active
...instead of a child of the a tag...
Copy.controls-container .flex-control-nav li a .flex-active
If you just think of it as a "string replacement" for a selector, it will help you visualize. For instance this (note where I have put the &)...
Copy.controls-container {
.flex-control-nav {
li a {
.flex-active & {
filter: none;
background: @color_links!important;
}
}
}
}
...would produce this selector...
Copy.flex-active .controls-container .flex-control-nav li a
...as it would append the nested structure after the class .flex-active.
Less.js
lesscss.org › features
Features In-Depth | Less.js
Less extends CSS with dynamic behavior such as variables, mixins, operations and functions. Less runs on both the server-side (with Node.js and Rhino) or client-side (modern browsers only).
Syncfusion
syncfusion.com › blogs › angular › less versus css
LESS versus CSS | Syncfusion Blogs
April 11, 2025 - You can either define static CSS ... also known as Leaner Style Sheets, is a dynamic CSS preprocessor that compiles and generates CSS during runtime on the server or client side....
Microsoft Learn
learn.microsoft.com › en-us › archive › msdn-magazine › 2013 › november › cutting-edge-programming-css-do-more-with-less
Cutting Edge - Programming CSS: Do More with 'LESS' | Microsoft Learn
This field of Web development started a few years ago and is now reaching maturity, as several available frameworks can help you out with dynamic CSS content generation. I’ll provide an executive summary of one of these frameworks—the LESS Framework—and show how it can be integrated with ...
DevDocs
devdocs.io › less
DevDocs — Less 4 documentation
Less 4.0.0 API documentation with instant search, offline support, keyboard shortcuts, mobile version, and more.
TutorialsPoint
tutorialspoint.com › less › index.htm
LESS Tutorial
LESS is a CSS pre-processor that enables customizable, manageable and reusable style sheet for website. LESS is a dynamic style sheet language that extends the capability of CSS.
TechAffinity
techaffinity.com › home › why you should use “less” css preprocessor? what is the difference between “less” & plain css?
What is "Less" CSS Preprocessor? When, Why and How to Use "Less"?
June 16, 2020 - The main difference between a plain CSS code and a CSS Preprocessor is that in plain CSS, your codes are static, and in preprocessors, you can write conditional codes to dynamically apply styles. ... “Less” is an acronym for Leaner Style Sheet. ...