Using sass lighten functions with variable not working - css

I am using SASS in my project with
Here if my variables code
:root, [data-theme="default"] {
--text-color: #383143;
}
$text-color: var(--text-color);
i am using that variable with lighten function like bellow,
body {
color: lighten($text-color, 10%);
}
I am getting the following error,
Error: argument $color of lighten($color, $amount) must be a color
on line 10 of assets/scss/base/typography.scss, in function lighten
How can I use lighten function with that variable? I need to use --text-color: #383143; that format for the color switcher purpose.

You can't use SASS variables in CSS variables as those are compiled before CSS is running. To solve this you could move the CSS variable to be defined by SASS, like this
$text-color: #383143;
:root, [data-theme="default"] {
--text-color: #{$text-color};
}

Related

Is there a way to define SASS variables in a" [data='value'] {}", or only regular CSS variables?

I want to export "$var" like variables defined as "--var" variables from a Scss file to be used in other files with some scss functions such as "darken()", but it says its not a color.
I'm coding a Vue/Vite website and implementing a theme-change button, that will write data at the HTML tag, and use it to define the theme.
<html lang="en" data-theme="dark"> ... </html>
The base.scss looks like this:
[data-theme="dark"] {
--primary: #c6c7df;
--secondary: #c95d63;
--text-light: #e2ebf5;
}
[data-theme="light"] {
--primary: #26298d;
--secondary: #c95d63;
--text-light: #2c3e50;
}
$primary: var(--primary);
$secondary: var(--secondary);
$text-light: var(--text-light);
I can use the "$var"-like variable at the end of the file, but when I use it inside a "darken($primary, 10%)" function, it gives the following error:
Error: $color: var(--primary) is not a color.
I know it's because I defined it as a CSS variable but if I define the variable inside the "[theme] {}" thing, it doesn't get innitialized and throws the error "Undefined variable"
I know it's a niche question, and I could use something like this, but I wish I could just export it as a scss variable.
Thank you very much.
Of course we cannot make a CSS variable lighten or darken. Think about, What will happen to the Name of CSS variable in the output?
So we have to define all CSS variables and assign desired colors, Before using them.
Solution
For this purpose, you can automatically create the list of CSS variables by #each and create a manual function by #function for easy use. This way gives us a standard css output and the best experience in Sass coding.
// Theme defines area:
$theme-colors:(
"primary": #940fe0,
"secondary": #e49f38,
"warning": #ffe600,
"info": #165ad6
);
$darken-percent: 20%;
$lighten-percent: 20%;
// Functions area:
:root {
#each $name, $color in $theme-colors {
$lighten: lighten($color, $lighten-percent);
$darken: darken($color, $darken-percent);
--color-#{$name}: #{$color};
--color-#{$name}-light: #{$lighten};
--color-#{$name}-dark: #{$darken};
}
}
#function cl($name, $color-tone) {
#if not map-get($theme-colors, $name+''){
#error "`#{$name}` is not defined in Colors Theme";
}
#if $color-tone == d {
#return var(--color-#{$name}-dark);
}
#if $color-tone == l {
#return var(--color-#{$name}-light);
}
#else{
#return var(--color-#{$name});
}
}
// Our custom function usage:
// Use 'b' to return Base color. Ex: cl(primary,b)
// Use 'l' to return Lighten color. Ex: cl(primary,l)
// Use 'd' to return Darken color. Ex: cl(primary,d)
.test {
color: cl(primary,b);
color: cl(warning,l);
}
Compiled css result:
:root {
--color-primary: #940fe0;
--color-primary-light: #bf61f4;
--color-primary-dark: #550980;
--color-secondary: #e49f38;
--color-secondary-light: #f0ca92;
--color-secondary-dark: #a06916;
--color-warning: #ffe600;
--color-warning-light: #fff066;
--color-warning-dark: #998a00;
--color-info: #165ad6;
--color-info-light: #6395ef;
--color-info-dark: #0c337a;
}
.test {
color: var(--color-primary);
color: var(--color-warning-light);

Css variables declared in :root block in styles.scss are invalid

In my angular 11 app I am trying to globally use css variables to declare global colors.
In my styles.scss I have:
:root{
--primary : #0b68e8;
--secondary:#ABCFFF;
}
.test-class{
background: var(--primary);
}
When I am applying that class in one of mine components I can see that var was not properly taken from declared variables:
I tried to find any solution , but cant resolve it. Do you maybe know what is wrong here?
try
.test-class{
background: #{var(--primary)};
}
BTW, if you're using sccs, why not use sass variables?
$primary: #0b68e8;
.test-class{
background: $primary;
}

How to combine LESS color functions and CSS Variables?

In my project I have a CSS custom variables like this:
:root {
--primary-color: #e04c4c;
--secondary-color: #2c2c5e;
--text-color: #d67900;
}
In my LESS files I have used LESS color functions to get more colors base on its primary and secondary. This is how its look like:
.component1 {
background: darken(--primary-color, 10%);
}
.component2 {
background: lighten(--secondary-color, 5%);
}
But when I compile this, it gives an error like this?
// Undefined_methodError: error evaluating function darken: //
Object # has no method 'toHSL'
When googling I found a solution for SASS, but not for LESS.
Can anybody tell me is there any possible workaround for this particular case?
Thank you.

Unable to set SCSS variable to CSS variable?

Consider the following SCSS:
$color-black: #000000;
body {
--color: $color-black;
}
When it is compiled with node-sass version 4.7.2, it produces following CSS:
body {
--color: #000000;
}
When I compile the same SCSS with version 4.8.3 or higher, it produces following:
body {
--color: $color-black;
}
What am I missing? I checked release logs, but could not found anything useful. Also, I wonder if this change is genuine why does it have only minor version change? Should it not be a major release?
Also, what is my alternative? Should I use Interpolation?
Just use string interpolation:
$color-black: #000000;
body {
--color: #{$color-black};
}
Apparently the old behaviour is not intended and violated the language specs of SASS:
CSS variables mixed with SCSS variables don't emit proper CSS in 4.8+
CSS variables aren't properly compiled
Assigning SASS variables to CSS Variables (Custom Properties) no longer works
scss and css
I found a workaround to mapping the scss variables to css variables.
See Terry's answer for better use
Scss:
// sass variable map
$colors: (
color-black: #FFBB00
);
// loop over each name, color
:root {
// each item in color map
#each $name, $color in $colors {
--#{$name}: #{$color};
}
}
Css:
:root {
--color-black: #FFBB00;
}
I had an issue with older sass versions.
Trying to compile a list of variables coming from an array, it would get stuck with the double dash. Here's my solution in case it helps someone
$var-element:'--';
:root {
#each $color in $color-variables {
#{$var-element}#{nth($color, 1)}: #{nth($color, 2)};
}
}

Can I create Less color themes with variables that rely on other variables?

Does anyone know how to do what I am attempting to do here?
#theme (dark) {#primary: black;}
#theme (light) {#primary: white;}
#theme (#_) {#primary: yellow;}
#name: dark;
#theme(#name);
.rule {
color: #primary;
}
I am trying to define a few "themes" which will have colors and images (possibly) that will be used throughout the various Less files. I have made do in the past with defining them globally and commenting out those that are not in use, but I am trying to see if there are people who have found better strategies in Less than what I have.
I had at one point found a feature that used to be (?) a part of Less but it doesn't seem to work.
.theme {
#color: red;
}
.rule {
color: .theme > #color;
}
This would be great, if it worked.
After a bit of messing with LESSCSS, I've come up with a reasonable way to change all variables based on a single #theme variable.
The trick is to use variable interpolation to specify a variable reference to a variable.
//this can be either "dark" or "light"
#theme: dark;
#theme-primary: "#{theme}-primary"; //this will evaluate to "dark-primary"
#theme-secondary: "#{theme}-secondary"; //this will evaluate to "dark-secondary"
#dark-primary: #F00;
#dark-secondary: #000;
#light-primary: #333;
#light-secondary: #FFF;
body {
//#theme-secondary evaluates to "dark-secondary"
//#dark-secondary evalutates to #000
background-color: ##theme-secondary;
//#theme-primary evaluates to "dark-primary"
//#dark-primary evaluates to #F00
color: ##theme-primary;
}
Older version
While I don't know of an easy way to conditionally define variables, if you're going to change one word and change a color theme, you might as well change an import statement:
#import ’themes/dark.less’;
//#import ’themes/light.less’;

Resources