I'm using the SMACSS method of writing my SCSS code, and I have a subclass that I want to reference if it also has another subclass.
HTML
<div class="parent-class parent-class-subclass1 parent-class-subclass2">
SCSS
.parent-class {
&-subclass1.&-subclass2 {
//Styles here
}
}
Any idea how I can do this?
So, when parent element also has subclass1 && subclass2, apply styles?
#katniss.everbean Yes, but the way you wrote it makes you have to duplicate the code.
After searching around for a while I stumbled upon this solution that works perfectly by writing any & references after the first one like #{&}:
SASS
.parent-class {
&#{&}-subclass1#{&}-subclass2{
border: 1px solid red;
}
}
Compiles into (CSS)
.parent-class.parent-class-subclass1.parent-class-subclass2 {
border: 1px solid red;
}
I found it on the SASS GitHub page.
...and I have a subclass that I want to reference if it also has another
subclass.
So, when parent element also has subclass1 && subclass2, apply styles?
You only need one & to join the nested selector to the parent class as a sibling. Then write the two subclasses as a regular sibling selector (next to each other without a space in between to indicate they're both required sibling classes).
The SCSS would look like this:
.parent-class {
//some styles
&.parent-class-subclass1.parent-class-subclass2 {
//subclass styles
}
}
That's equivelant to the following CSS
.parent-class {
//some styles
}
.parent-class.parent-class-subclass1.parent-class-subclass2 {
//some other styles
}
To keep your modular naming structure and not have to write out the whole subclass name, you could try using wildcard selectors. I'm not sure it actually ends up looking any better than just writing out the whole class name though.
Here's a codepen that demonstrates:
http://codepen.io/anon/pen/vXKZYA
And the basic code in that pen for posterity:
<div class="parent-class parent-class-subclass1 parent-class-subclass2">
some text that has all the goods
</div>
.parent-class {
color: #0000ff;
&[class*="-subclass1"][class*="-subclass2"] {
font-size: 20px;
font-family: sans-serif;
}
}
you should do it like this
<div class="parent-class subclass1 subclass2">
.parent-class {
&.subclass1.subclass2 {
//Styles here
}
}
or you can even do it like this
.parent-class {
&.subclass1 {
//subclass1 Styles here
&.subclass2 {
//subclass1 & 2 Styles here
}
}
}
I am trying to figure out the best way to accomplish reusing some of the nested styles in Less to prevent duplication, but I am not sure if I have found the best way.
Right now I have something like:
.category-link,
.caption-link {
background-color: #linkColour;
font-family: #linkFont;
max-width:2em;
a {
/* INNER LINK STYLES */
text-decoration:none;
white-space:nowrap;
/* ...INNER LINK STYLES CONTINUE... */
}
}
Now I want to apply those same inner link styles to the selector .action-link a without applying the outer styles to .action-link.
I get my intended output if I do it this way:
.inner-link-styles() {
/* INNER LINK STYLES */
text-decoration:none;
white-space:nowrap;
/* ...INNER LINK STYLES CONTINUE... */
}
.category-link,
.caption-link {
background-color: #linkColour;
font-family: #linkFont;
max-width:2em;
a {
.inner-link-styles;
}
}
.action-link a {
.inner-link-styles;
}
which doesn't require any duplication, but I'd prefer to keep those styles in their current location, where they are relevant, than to move them out to mixins.less and increase complexity for the next developer to troubleshoot.
What felt intuitive, but is clearly wrong, was something like this:
.category-link,
.caption-link {
background-color: #linkColour;
font-family: #linkFont;
max-width:2em;
& a,
.action-link a {
/* INNER LINK STYLES */
text-decoration:none;
white-space:nowrap;
/* ...INNER LINK STYLES CONTINUE... */
}
}
but is there some other prefix I can apply to a selector to have it based absolutely, rather than relative to it's nesting level?
Absolute selectors can't be added within a nested block because once we nest it under another block, the inner selector is considered as a child of the outer one (like in the DOM) unless we add &. to the selector (in which case, the inner one could be another class on the parent itself).
Using mixins or the :extend feature are the best options for your case because you are assigning a set of common properties to multiple elements.
Since parent selector is known (it is either .category-link a or .caption-link a), you can extend the properties of that selector into .action-link a also. This would extend only the properties of the inner link and not that of its parent.
I don't think this increases the complexity for the next developer to troubleshoot because changing the properties in the original .category-link a will change the properties for .action-link a also.
.category-link,
.caption-link {
background-color: blue;
font-family: Arial;
max-width:2em;
a {
/* INNER LINK STYLES */
text-decoration:none;
white-space:nowrap;
/* ...INNER LINK STYLES CONTINUE... */
}
}
.action-link {
a {
&:extend(.category-link a);
}
}
I've been reading about CSS and I am really confused about how the inheritance works (I think thats the right term for the following). In CSS I can declare a class:
#mytext {
}
then I see some people do:
p.mytext {
}
But why do that? Why can't they just do:
<p class="mytext">
Without declaring p.mytext? Does it make sense what I am asking?
and sometimes i see:
p#mytext ... Why is it different? I'll keep searching tutorials but thanks for any advise.
The pound sign (#) refers to an ID which needs to be unique for the page. The period (.) refers to a class which can be used many times. People would use p#mytext if they wanted a unique styling for one (just one) paragraph tag.
You can read up about it here.
Wanted to add that some web developers seem to gravitate towards declaring everything as classes. If you use a layout generator of any kind more often than not every element will be a class.
#mytext references <p id="mytext"/> (doesn't need to be a p element, #mytext just refers to that ID)
Whereas .mytext references <p class="mytext"/> (doesn't need to be p element, .mytext just refers to anything with that classname)
By adding other things such as p.mytext you create a stronger bind to your rule, for instance:
p.mytext { color:white; } .mytext { color:black; }
may at first seem like the color would be black, however as you have created a stronger bind (by being more specific earlier) the actual color will be white.
First check this question here.
In short # represents an ID in css, and . represents a class. if you say p#myText in your css it means you have a <p id="myText"></p> in your html, and p.myText is for <p class="myText"></p>.
Furthermore you declare an ID if you have an unique item in your html, and if you have multiple elements with same styles you declare a class for them.
CSS 101 - the basics
CSS - all elements
* { ... }
HTML - basic element
<p></p>
CSS
p { ... }
HTML - element with id
<p id="someid"></p>
CSS - element with id
p#someid { ... }
CSS - all id's
#someid { ... }
HTML - element with class
<p class="someclass"></p>
CSS - element with class
p.someclass { ... }
CSS - all elements with class
.someclass { ... }
CSS - is equal to
*.someclass { ... }
HTML - element with both id and class
<p id="someid" class="someclass"></p>
CSS
p#someid.someclass { ... }
HTML - nested element
<p><span></span></p>
CSS
p span { ... }
HTML - nested element with id
<p><span id="someid"></span></p>
CSS
p span#someid { ... }
HTML - nested element with class
<p><span class="someclass"></span></p>
CSS
p span.someclass { ... }
HTML - nested element with id in element with class
<p class="someclass"><span id="someid"></span></p>
CSS
p.someclass span#someid { ... }
now you can mix and match all those things up to make really complicated selectors
if you want multiple selectors with the same properties you can seperate them with a comma
p.someclass, span#someid { ... }
A hash (#) is a unique ID definition.
#foo { color: blue; }
<div id="foo">
A dot (.) is a class definition.
.bar { color: red; }
<div class="bar">
But you can also refer to tags with certain classes and ID's:
div.baz { color: green; }
span#qux { color: yellow; }
<div class="baz">
<span id="qux">
+1 for the interesting question.
First, you have it backwards, . (period) is class and # is ID. You probably already know this, but an element can only have one ID and you should only have that ID defined once on your page.
As for the second part of your question, some people like to append the element name to their classes and IDs. It's just more specific that not having it defined.
img.large { width 200px /* Only applies to img with large class */ }
textarea.large { width: 300px /* Only applies to textareas with large class */ }
p#large { font-size: 1.5em; /* Only applies to p with ID of large */ }
.large { font-size: 2em; /* Applies to any element with class of large */ }
Personally, I like to append the element name in my styles so that I don't forget which elements it is affecting.
lets say you have the following HTML:
<div id="main">
<p class="para">content</p>
<p class="para">content</p>
</div>
then:
div#main { }
references divs with the id of "main"
#main { }
references all elements that have the id of "main"
p.para { }
references all p elements with the class of "para"
.para { }
references ALL elements with the class "para"
NB. An ID must be unique on the page whereas a class can be used multiple times
Is it possible to make a CSS class that "inherits" from another CSS class (or more than one).
For example, say we had:
.something { display:inline }
.else { background:red }
What I'd like to do is something like this:
.composite
{
.something;
.else
}
where the ".composite" class would both display inline and have a red background
There are tools like LESS, which allow you to compose CSS at a higher level of abstraction similar to what you describe.
Less calls these "Mixins"
Instead of
/* CSS */
#header {
-moz-border-radius: 8px;
-webkit-border-radius: 8px;
border-radius: 8px;
}
#footer {
-moz-border-radius: 8px;
-webkit-border-radius: 8px;
border-radius: 8px;
}
You could say
/* LESS */
.rounded_corners {
-moz-border-radius: 8px;
-webkit-border-radius: 8px;
border-radius: 8px;
}
#header {
.rounded_corners;
}
#footer {
.rounded_corners;
}
You can add multiple classes to a single DOM element, e.g.
<div class="firstClass secondClass thirdclass fourthclass"></div>
Rules given in later classes (or which are more specific) override. So the fourthclass in that example kind of prevails.
Inheritance is not part of the CSS standard.
Yes, but not exactly with that syntax.
.composite,
.something { display:inline }
.composite,
.else { background:red }
Keep your common attributes together and assign specific (or override) attributes again.
/* ------------------------------------------------------------------------------ */
/* Headings */
/* ------------------------------------------------------------------------------ */
h1, h2, h3, h4
{
font-family : myfind-bold;
color : #4C4C4C;
display:inline-block;
width:900px;
text-align:left;
background-image: linear-gradient(0, #F4F4F4, #FEFEFE);/* IE6 & IE7 */
}
h1
{
font-size : 300%;
padding : 45px 40px 45px 0px;
}
h2
{
font-size : 200%;
padding : 30px 25px 30px 0px;
}
The SCSS way for the given example, would be something like:
.something {
display: inline
}
.else {
background: red
}
.composite {
#extend .something;
#extend .else;
}
More info, check the sass basics
An element can take multiple classes:
.classOne { font-weight: bold; }
.classTwo { font-famiy: verdana; }
<div class="classOne classTwo">
<p>I'm bold and verdana.</p>
</div>
And that's about as close as you're going to get unfortunately. I'd love to see this feature, along with class-aliases someday.
No you can't do something like
.composite
{
.something;
.else
}
This are no "class" names in the OO sense. .something and .else are just selectors nothing more.
But you can either specify two classes on an element
<div class="something else">...</div>
or you might look into another form of inheritance
.foo {
background-color: white;
color: black;
}
.bar {
background-color: inherit;
color: inherit;
font-weight: normal;
}
<div class="foo">
<p class="bar">Hello, world</p>
</div>
Where the paragraphs backgroundcolor and color are inherited from the settings in the enclosing div which is .foo styled. You might have to check the exact W3C specification. inherit is default for most properties anyway but not for all.
I ran into this same problem and ended up using a JQuery solution to make it seem like a class can inherit other classes.
<script>
$(function(){
$(".composite").addClass("something else");
});
</script>
This will find all elements with the class "composite" and add the classes "something" and "else" to the elements. So something like <div class="composite">...</div> will end up like so: <div class="composite something else">...</div>
You can do is this
CSS
.car {
font-weight: bold;
}
.benz {
background-color: blue;
}
.toyota {
background-color: white;
}
HTML
<div class="car benz">
<p>I'm bold and blue.</p>
</div>
<div class="car toyota">
<p>I'm bold and white.</p>
</div>
Don't forget:
div.something.else {
// will only style a div with both, not just one or the other
}
You can use the converse approach to achieve the same result - start from the composite and then remove styling using the unset keyword. For example, if you start with the following sample composition:
.composite {
color: red;
margin-left: 50px;
background-color: green
}
you can then increase selector specificity to selectively remove styles using unset:
.composite.no-color {
color: unset
}
.composite.no-margin-left {
margin-left: unset
}
.composite.no-background-color {
background-color: unset
}
Here is a JSFiddle demonstrating this approach.
One benefit of this approach is that because the specificity of the compound selectors is higher than the composite itself, you do not need all of the combinations of classes to achieve the desired results for multiple combinations:
/* Multi-unset compound selector combinations, such as the one that follows, ARE NOT NECESSARY because of the higher specificity of each individual compound selectors listed above. This keeps things simple. */
.composite.no-background-color.no-color.no-margin-left {
background-color: unset;
color: unset;
margin-left: unset
}
Furthermore, at 96% support for the unset keyword, browser coverage is excellent.
Perfect timing: I went from this question to my email, to find an article about Less, a Ruby library that among other things does this:
Since super looks just like footer, but with a different font, I'll use Less's class inclusion technique (they call it a mixin) to tell it to include these declarations too:
#super {
#footer;
font-family: cursive;
}
In Css file:
p.Title
{
font-family: Arial;
font-size: 16px;
}
p.SubTitle p.Title
{
font-size: 12px;
}
I realize this question is now very old but, here goes nothin!
If the intent is to add a single class that implies the properties of multiple classes, as a native solution, I would recommend using JavaScript/jQuery (jQuery is really not necessary but certainly useful)
If you have, for instance .umbrellaClass that "inherits" from .baseClass1 and .baseClass2 you could have some JavaScript that fires on ready.
$(".umbrellaClass").addClass("baseClass1");
$(".umbrellaClass").addClass("baseClass2");
Now all elements of .umbrellaClass will have all the properties of both .baseClasss. Note that, like OOP inheritance, .umbrellaClass may or may not have its own properties.
The only caveat here is to consider whether there are elements being dynamically created that won't exist when this code fires, but there are simple ways around that as well.
Sucks css doesn't have native inheritance, though.
Unfortunately, CSS does not provide 'inheritance' in the way that programming languages like C++, C# or Java do. You can't declare a CSS class an then extend it with another CSS class.
However, you can apply more than a single class to an tag in your markup ... in which case there is a sophisticated set of rules that determine which actual styles will get applied by the browser.
<span class="styleA styleB"> ... </span>
CSS will look for all the styles that can be applied based on what your markup, and combine the CSS styles from those multiple rules together.
Typically, the styles are merged, but when conflicts arise, the later declared style will generally win (unless the !important attribute is specified on one of the styles, in which case that wins). Also, styles applied directly to an HTML element take precedence over CSS class styles.
Don't think of css classes as object oriented classes, think of them as merely a tool among other selectors to specify which attribute classes an html element is styled by. Think of everything between the braces as the attribute class, and selectors on the left-hand side tell the elements they select to inherit attributes from the attribute class. Example:
.foo, .bar { font-weight : bold; font-size : 2em; /* attribute class A */}
.foo { color : green; /* attribute class B */}
When an element is given the attribute class="foo", it is useful to think of it not as inheriting attributes from class .foo, but from attribute class A and attribute class B. I.e., the inheritance graph is one level deep, with elements deriving from attribute classes, and the selectors specifying where the edges go, and determining precedence when there are competing attributes (similar to method resolution order).
The practical implication for programming is this. Say you have the style sheet given above, and want to add a new class .baz, where it should have the same font-size as .foo. The naive solution would be this:
.foo, .bar { font-weight : bold; font-size : 2em; /* attribute class A */}
.foo { color : green; /* attribute class B */}
.baz { font-size : 2em; /* attribute class C, hidden dependency! */}
Any time I have to type something twice I get so mad! Not only do I have to write it twice, now I have no way of programatically indicating that .foo and .baz should have the same font-size, and I've created a hidden dependency! My above paradigm would suggest that I should abstract out the font-size attribute from attribute class A:
.foo, .bar, .baz { font-size : 2em; /* attribute base class for A */}
.foo, .bar { font-weight : bold; /* attribute class A */}
.foo { color : green; /* attribute class B */}
The main complaint here is that now I have to retype every selector from attribute class A again to specify that the elements they should select should also inherit attributes from attribute base class A. Still, the alternatives are to have to remember to edit every attribute class where there are hidden dependencies each time something changes, or to use a third party tool. The first option makes god laugh, the second makes me want to kill myself.
That's not possible in CSS.
The only thing supported in CSS is being more specific than another rule:
span { display:inline }
span.myclass { background: red }
A span with class "myclass" will have both properties.
Another way is by specifying two classes:
<div class="something else">...</div>
The style of "else" will override (or add) the style of "something"
As others have said, you can add multiple classes to an element.
But that's not really the point. I get your question about inheritance. The real point is that inheritance in CSS is done not through classes, but through element hierarchies. So to model inherited traits you need to apply them to different levels of elements in the DOM.
While direct inheritance isn't possible.
It is possible to use a class (or id) for a parent tag and then use CSS combinators to alter child tag behaviour from it's heirarchy.
p.test{background-color:rgba(55,55,55,0.1);}
p.test > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span > span > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span > span > span > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span > span > span > span > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span > span > span > span > span > span{background-color:rgba(55,55,55,0.1);}
p.test > span > span > span > span > span > span > span > span{background-color:rgba(55,55,55,0.1);}
<p class="test"><span>One <span>possible <span>solution <span>is <span>using <span>multiple <span>nested <span>tags</span></span></span></span></span></span></span></span></p>
I wouldn't suggest using so many spans like the example, however it's just a proof of concept. There are still many bugs that can arise when trying to apply CSS in this manner. (For example altering text-decoration types).
I was looking for that like crazy too and I just figured it out by trying different things :P... Well you can do it like that:
composite.something, composite.else
{
blblalba
}
It suddenly worked for me :)
In specific circumstances you can do a "soft" inheritance:
.composite
{
display:inherit;
background:inherit;
}
.something { display:inline }
.else { background:red }
This only works if you are adding the .composite class to a child element. It is "soft" inheritance because any values not specified in .composite are not inherited obviously. Keep in mind it would still be less characters to simply write "inline" and "red" instead of "inherit".
Here is a list of properties and whether or not they do this automatically:
https://www.w3.org/TR/CSS21/propidx.html
Less and Sass are CSS pre-processors which extend CSS language in valuable ways. Just one of many improvements they offer is just the option you're looking for. There are some very good answers with Less and I will add Sass solution.
Sass has extend option which allows one class to be fully extended to another one. More about extend you can read in this article
I think this one is a better solution:
[class*=“button-“] {
/* base button properties */
}
.button-primary { ... }
.button-plain { ... }
Actually what you're asking for exists - however it's done as add-on modules. Check out this question on Better CSS in .NET for examples.
Check out Larsenal's answer on using LESS to get an idea of what these add-ons do.
CSS doesn't really do what you're asking. If you want to write rules with that composite idea in mind, you may want to check out compass. It's a stylesheet framework which looks similar to the already mentioned Less.
It lets you do mixins and all that good business.
For those who are not satisfied with the mentioned (excellent) posts, you can use your programming skills to make a variable (PHP or whichever) and have it store the multiple class names.
That's the best hack I could come up with.
<style>
.red { color: red; }
.bold { font-weight: bold; }
</style>
<? define('DANGERTEXT','red bold'); ?>
Then apply the global variable to the element you desire rather than the class names themselves
<span class="<?=DANGERTEXT?>"> Le Champion est Ici </span>
Have a look at CSS compose:
https://bambielli.com/til/2017-08-11-css-modules-composes/
according to them:
.serif-font {
font-family: Georgia, serif;
}
.display {
composes: serif-font;
font-size: 30px;
line-height: 35px;
}
I use it in my react project.
If you want a more powerful text preprocessor than LESS, check out PPWizard:
http://dennisbareis.com/ppwizard.htm
Warning the website is truly hideous and there's a small learning curve, but it's perfect for building both CSS and HTML code via macros. I've never understood why more web coders don't use it.
You can achieve what you want if you preprocess your .css files through php.
...
$something='color:red;'
$else='display:inline;';
echo '.something {'. $something .'}';
echo '.else {'. $something .'}';
echo '.somethingelse {'. $something .$else '}';
...