Ampersand

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 7 min read
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First a re-cap of the basic CSS Chain/Descendant Selector 1> Chain Selectors - https://stackoverflow.com/questions/13444647/css-class-definition-with-multiple-identifiers .class1.class2 will match only the elements that have both of the classes defined. .class1.class2 { background: red; } <div class="class1 class2"></div> 2> Descendant Selector The descendant selector matches all elements that are descendants of a specified element. And the Per Official doc .class1 .class2 { background: red; } 3> Child Selector The child...

Key Takeaways

  • This article explains css class definition with multiple identifiers in a single line – Understaning how it works in simple medical language.
  • This article explains 1> Chain Selectors - in simple medical language.
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First a re-cap of the basic CSS Chain/Descendant Selector

1> Chain Selectors –

https://stackoverflow.com/questions/13444647/css-class-definition-with-multiple-identifiers

.class1.class2 will match only the elements that have both of the classes defined.

.class1.class2 { background: red; }

<div class="class1 class2"></div>

2> Descendant Selector

The descendant selector matches all elements that are descendants of a specified element.

And the Per Official doc

.class1 .class2 { background: red; }

3> Child Selector

The child selector selects all elements that are the children of a specified element.

The following example selects all

elements that are children of a

element:

div > p {
    background-color: yellow;
}

The meaning of a selector with more classes depends on how you combine them in your declarations:

dot notation vs ampersand

Basic Nesting with dot (“.”)

.parent {
    .child {
    }
}

This compiles to:

.parent .child {}

You can nest as deep as you’d like, but it’s a good practice to keep it only a level or two to prevent overly specific selectors (which are less useful and harder to override).

The & comes in handy when you’re nesting and you want to create a more specific selector, like an element that has both of two classes, like this:

.some-class.another-class { }

.some-class {
    &.another-class {
    }
}

This will compile to

.some-class.another-class

The & always refers to the parent selector when nesting. We can think of the & as a mechanism that allows us to place the parent selector wherever we need it in our child selector.

Using the & with pseudo classes

You can write pseudo classes on a class in a much less repetitive way with the &:

    .button {
  &:visited { }
  &:hover { }
  &:active { }
}

This compiles to:

.button:visited {
}
.button:hover {
}
.button:active {
}

The & in this case allows us to position .button directly next to pseudo classes without repetition in the authored code. If we left out the & from this example, basic nesting would put a space between them like this…

.button :hover

which isn’t the same.

And thats why at the root of the .scss file I can not have an ampersand &


&.sdk-ng-select .ng-dropdown-panel {
  @include sdk-ng-select();
}

It will give me following error

SassError: Base-level rules cannot contain the parent-selector-referencing character

.pagination {
  a {
    &:hover,
    &:focus {
      color: red;
    }
  }
}

// in this case, the & represents .pagination a, and will compile to:

.pagination a:hover, 
.pagination a:focus {
  color: red;
}

Another example

  .hoverable {
  color: #fff;
  &:hover {
    color: #ff0;
  }
}

The compiled CSS will be

  .hoverable {
  color: #fff;
}

// just replace the "&" with the parent selector (.hoverable)

.hoverable:hover {
  color: #ff0;
}

Nested ampersand – Very useful

The cool thing about ampersands is that they don’t only have to be at the beginning of a nested style definition.

Wherever you put an ampersand into your Sass selector definitions, it is interpreted to mean the parent scope of the current style being defined.

An application of the above is – sometimes you need to define a style that takes the context of the existing style, but only applies in a special case. For example, what if we need a different border treatment for our .hoverableelement when the parent class is .special

The SASS without a nested “&” would be below

.hoverable {
  color: #fff;
  &:hover {
    color: #ff0;
  }
}

.special .hoverable {
  border: 1px solid #f00;
}

Doing this required us to step out of our .hoverable selector and then re-define it inside a new selector. If there had been more levels of nesting, or more context that needed to be set, that could have been a fairly complex action.

But with the ampersand, Sass allows us to do the same thing without leaving the scope of the .hoverable selector:

.hoverable {
  color: #fff;
  &:hover {
    color: #ff0;
  }
  .special & {
    border: 1px solid #f00;
  }
}

Both of these Sass snippets will result in the following CSS:

.hoverable {
  color: #fff;
}

.hoverable:hover {
  color: #ff0;
}

.special .hoverable {
  border: 1px solid #f00;
}

Sass replaced the ampersand with the parent selector, defining a new selector inside of the .special selector. And note because here, there a single space before the “&” – so the generated css will also have a single space before the parent selector (i.e. before .hoverable )

Since & references the top-most selector, it can be extended with additional classes and/or an id like the pseudo class selectors. So let’s say there is a selector of .feature-class and we have an instance where it will be paired with .style-class, which changes the look of it. From within the .feature-class declaration block, we would have a child declaration that starts like this: &.style-class with its own declaration block.

Sass will replace “&” with .feature-class, which becomes feature-class.style-class in our generated CSS.

.feature-class {
        color: #0090B2;
        &:hover {
          color: #FF7A00;
        }
        &:active {
          color: #B25500;
        }
        &.style-class {
          color: #00CEFF;
          &:hover {
            color: #0090B2;
          }
          &:active {
            color: #FF7A00;
          }
        }
      }

Generated CSS

.feature-class {
      color: #0090B2;
    }
    .feature-class:hover {
      color: #FF7A00;
    }
    .feature-class:active {
      color: #B25500;
    }
    .feature-class.style-class {
      color: #00CEFF;
    }
    .feature-class.style-class:hover {
      color: #0090B2;
    }
    .feature-class.style-class:active {
      color: #FF7A00;
    }

css class definition with multiple identifiers in a single line – Understaning how it works

1> Chain Selectors –

https://stackoverflow.com/questions/13444647/css-class-definition-with-multiple-identifiers

.class1.class2 will match only the elements that have both of the classes defined.

.class1.class2 { background: red; }

<div class="class1 class2"></div>

.class1, .class2 (i.e. a comma and a space in between) will match the elements with .class1 or .class2

.class1, class2 { background: yellow; }

<div class="class1"></div>
<div class="class2"></div>

Chain selectors are not limited just to classes, you can do it for both classes and ids.

Classes

.classA.classB {
/*style here*/
}

Class & Id

.classA#idB {

/*style here*/
}

Id & Id

#idA#idB {
/*style here*/
}

2> Descendant Selector

.class1 .class2 will match only the elements with class2 within elements with class1.

.class1 .class2 { background: blue; }

<div class="class1">
    <div class="class2"></div>
</div>

3> Child Selector

The child selector selects all elements that are the children of a specified element.

The following example selects all

elements that are children of a

element:

div > p {
    background-color: yellow;
}

I was working ng-select Angular package, and for my case here, I am trying to target both the below 2 classes

class="ng-select ng-dropdown-panel"

// And also
class="ng-dropdown-panel sdk-ng-select"

Note when I use component (which is the popular angular package) in .html file all ng-select related classes will have the ultimate parent ‘ng-select’

Here’s my overall structur of the @mixin in .scss file

@mixin sdk-ng-select {
    ...many styles here
.ng-dropdown-panel,
  &.ng-dropdown-panel.sdk-ng-select {
    .ng-dropdown-footer {
      @extend .sdk-text-body-light-2;
      display: flex;
      align-items: center;
      justify-content: center;      
    }
...many styles here
}

.sdk-ng-select {
  @include sdk-ng-select();
}

Then in an .html file of Angular component was consuming the above style as below

<ng-select class=”sdk-ng-select”

The above will work, but its the wrong way to handle.

Problem with above

&.ng-dropdown-panel.sdk-ng-select should not be required.

I could simply do

.ng-dropdown-panel, &.ng-dropdown-panel

In the above, the first selector (.ng-dropdown-panel) matches “ng-dropdown-panel” inside the “ng-select”

The second selector (&.ng-dropdown-panel) matches

i.e. both the classes

.ng-dropdown-panel.sdk-ng-select

Recollect, the way ampersand work, that it will replace “&” with .parent-class, which becomes

.ng-dropdown-panel.sdk-ng-select in our generated CSS.

The downside to repeating the .sdk-ng-select selector inside the mixing (as I was doing in the top of this page) is that mixin is made in a way where it does not know about the class .sdk-ng-select, instead, it is used inside it, like below.

  .sdk-ng-select {
  @include sdk-ng-select();
}

And having the selector .sdk-ng-select inside the mixin breaks this structure.

So the correct version would be

  .ng-dropdown-panel,
  &.ng-dropdown-panel {
    .ng-dropdown-footer {
      @extend .sdk-text-body-light-2;
      display: flex;
      
    }

The meaning of a selector with more classes depends on how you combine them in your declarations:

Relevant issue in Saas github repo

“This error has existed since 3.0 which was released in May 2010.

It’s nonsensical to refer to a parent selector at the base-level of a stylesheet. Inferring that & should be the universal selector at the root level is not at all a safe assumption. Additionally, this is often indicative of a coding mistake. So we consider it an error.”

Further Reading

https://css-tricks.com/the-sass-ampersand/

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What to tell the doctor

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Safe first steps

  • Rest, drink safe water, and observe symptoms carefully.
  • Keep a written note of symptoms, duration, temperature, medicines already taken, and allergy history.
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OTC medicine safety

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  • Do not give adult medicines to children unless a qualified clinician advises it.

Avoid these mistakes

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Get urgent help if

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Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

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Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
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Questions to ask
  • What is the most likely cause of my symptoms?
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Go to emergency care if you notice:
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Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

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  4. Step 4

    Do only useful tests

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  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

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