Why Doesn't This CSS :Not() Declaration Filter Down

Why doesn't this CSS :not() declaration filter down?

Both of the span elements' parent div elements don't have the class no, regardless of whether any other ancestors do have it or not:

<div> <!-- This is div:not(.no), pretty much a given -->
    <span>yes 1</span>
</div>

<div class="no"> <!-- In this case, although this is div.no... -->
    <div>        <!-- ... this is div:not(.no)! -->
           <span>no 2</span>
    </div>
</div>

Both html and body, which are ancestors of your div and span elements, satisfy *:not(.no) when using a universal selector (or rather, when omitting a type selector). This causes all of your span elements to have the background color.

One solution to this is to anchor your negation filter to the body element using the child combinator, if your top-level div elements will always be children of body:

body > div:not(.no) span { background-color: #00f; }

jsFiddle demo

Another solution is to simply use override styles.

CSS not selector not working

$('input').not('.exclude *')

$('input:not(.exclude *)')

These will grab all inputs which are not descendants of elements with the exclude class. You can get more specific on which inputs (maybe only the ones under a certain div or class) but this should get you the exclusion you're looking for.

You can see a working example here

Cascading with CSS :not pseudo-class

Since there is nothing between <div class="exclude"> and its direct child <p>, it should trigger the rule regardless of what it is nested inside. What am I missing?

The <p> is a descendant of both the top-level <div> and <div class="exclude">. So while the latter doesn't match the selector, the former does, and therefore you have a match. It doesn't matter either that the ancestor that fails to match the selector is closer to the <p> than the one that does.

Solutions 1 and 2 work by eliminating that match altogether.

Solution 3 works when no other <div>s exist in the <p>'s ancestry, because then you restrict your selector to those exact criteria, in that exact order. Which means if you swapped the class attribute from the inner <div> to the outer one, it would no longer match the selector, and conversely if you swapped the class selector from the inner div to the outer one, the selector would not match the original HTML structure (again, assuming no other <div>s exist in the hierarchy).

Wrapping another <div> around the <section> just causes the selector to be matched again by that <div>. The <section> is ignored, in much the same way as <div class="exclude">.

CSS : :not(s) selector as parent selector + :hover on classes misunderstanding

Thank you jhpratt, your answer helped me understand that the :not(s) was indeed applied on the html element. As Temani Afif guessed, in my code the btn is not a direct child of the body ; but here is what I was looking for :

body:not(.mobile) .btn:hover { ... }

complete solution : https://jsfiddle.net/162tn8ko/6/

Is the CSS :not() selector supposed to work with distant descendants?

Is this supposed to work like I think it should?

No, the behavior you're seeing is correct.

In your last example, although the <blockquote> contains a <p>, it's the <blockquote> itself that's matching *:not(p), as well as the condition that it must be a descendant of the <div>, which it is. The style is applied only to the <blockquote>, but it is then inherited by the <p> inside it.

The <p> element itself still counts against the negation, so the <p> itself is still being excluded from your selector. It's just inheriting the text color from its parent, the <blockquote> element.

Even if none of its relatively close ancestors matched the selector, you have elements like html and body to worry about as well — although you could probably just tack on a body selector in the very beginning:

body div...

This is why I often strongly advise against using the :not() selector for filtering descendants, especially when not qualified with a type selector (like div in your example). It doesn't work the way most people expect it to, and the use of inherited properties like color only serves to compound the problem, on top of making it even more confusing for authors. See my answers to these other questions for more examples:

Why doesn't this CSS :not() declaration filter down?
CSS negation pseudo-class :not() for parent/ancestor elements

The solution to the problem described is to simply apply a different color to <p> elements. You won't be able to simply exclude them with a selector because of inheritance:

/* Apply to div and let all its descendants inherit */
div {
  color: red;
}

/* Remove it from div p */
div p {
  color: black;
}

On Selectors Level 4: yes, :not() has indeed been enhanced to accept full complex selectors that contain combinators. Essentially, this means (once browsers begin implementing it) you will be able to write the following selector and have it do exactly what you want:

p:not(div p) {
  color: red;
}

In case anyone is interested, this works in jQuery today.

Why is my CSS style not being applied?

Have you tried forcing the selectors to be in the front of the class?

p span label.fancify {

    font-size: 1.5em;
    font-weight: 800;
    font-family: Consolas, "Segoe UI", Calibri, sans-serif;
    font-style: italic;
}

Usually it will add more weight to your CSS declaration.
My mistake ... There should be no space between the selector and the class.
The same goes for the ID. If you have for example:

<div id="first">
    <p id="myParagraph">Hello <span class="bolder">World</span></p>
</div>

You would style it like this:

div#first p#myParagraph {
     color : #ff0000;
}

Just to make a complete example using a class:

div#first p#myParagraph span.bolder{
    font-weight:900;
}

For more information about pseudo-selectors and child selectors : http://www.w3.org/TR/CSS2/selector.html

CSS is a whole science :) Beware that some browsers can have incompatibilities and will not show you the proper results. For more information check this site: http://www.caniuse.com/

Apply CSS to any element except for certain class descendants?

You will not be able to exclude descendants this way without writing a separate selector. You won't be able to do this even using :not(), for the reasons stated here.

Fortunately, the fact that .light elements will only ever occur within the context of a .dark element and not vice versa makes this a little easier. Since you have a body CSS rule already, just add .light p to that rule, and move the entire ruleset underneath .dark p so .light p will take precedence:

.dark p {
    color: #000;
}

body, .light p {
    color: #ccc;
}

Updated fiddle

Alternatively if you want to keep the body rule on top, you could bump up the specificity of .light p to ensure it will take precedence:

body, body .light p {
    color: #ccc;
}

.dark p {
    color: #000;
}

Font Family Declaration Doesn't Work

tl;dr: always load resets and external resources before loading your site's custom CSS resources.

Explanation

What you've got here is a specificity issue with your reset CSS code.

When two CSS rules conflict with each other, the browser will use the one with the most specific selector of the two (or, in the case of equal specificity, it uses the last rule loaded).

The Mozilla Developer's Network defines "Specificity" as:

The specificity is a weight that is applied to a given CSS declaration based on the count of each selector type. In the case of specificity equality, the latest declaration found in the CSS is applied to the element. Specificity only applies when the same element is targeted. CSS rules that directly target an element will always take precedence over rules that an element inherits from an ancestor.

You said you're using Meyer's CSS Reset. That file contains a line that says font: inherit, which directly conflicts with your font-family rule (as well as your font-size). In this case, you've fallen prey to the last sentence in that definition of specificity: the reset's font property is being applied to paragraphs, headings, lists, etc., and "rules that directly target an element will always take precedence over rules that an element inherits from an ancestor" (in this case, the ancestor being the body.

You've got a couple of options here. First of all, double check that you're loading your CSS after the reset. That might fix it, but it might not. You can make your selector more specific than the selectors in the reset, which shouldn't be hard since they are designed to use the lowest specificity possible. This is why using body * as a selector worked.

The third option is one that is not recommended: using an !important decorator on any rules that you want to be treated as higher-priority than all other rules. This is dangerous, because it can easily cause unanticipated collisions.

Examples

Non-Working Example: Here is an example that doesn't work. This example doesn't work because Stack Snippets loads the CSS section before the HTML section -- since I'm including the reset in the HTML section, and since both CSS resources have a conflicting same-specifity rule, the most recently-loaded rule gets applied.

body {  font-family: 'Lato', sans-serif;}

<link rel="stylesheet" href="http://meyerweb.com/eric/tools/css/reset/reset.css" type="text/css"><link href="http://fonts.googleapis.com/css?family=Lato" rel="stylesheet" type="text/css">
<p>Hello, world</p>

Reset/remove CSS styles for element only

The CSS3 keyword initial sets the CSS3 property to the initial value as defined in the spec. The initial keyword has broad browser support except for the IE and Opera Mini families.

Since IE's lack of support may cause issue here are some of the ways you can reset some CSS properties to their initial values:

.reset-this {
    animation : none;
    animation-delay : 0;
    animation-direction : normal;
    animation-duration : 0;
    animation-fill-mode : none;
    animation-iteration-count : 1;
    animation-name : none;
    animation-play-state : running;
    animation-timing-function : ease;
    backface-visibility : visible;
    background : 0;
    background-attachment : scroll;
    background-clip : border-box;
    background-color : transparent;
    background-image : none;
    background-origin : padding-box;
    background-position : 0 0;
    background-position-x : 0;
    background-position-y : 0;
    background-repeat : repeat;
    background-size : auto auto;
    border : 0;
    border-style : none;
    border-width : medium;
    border-color : inherit;
    border-bottom : 0;
    border-bottom-color : inherit;
    border-bottom-left-radius : 0;
    border-bottom-right-radius : 0;
    border-bottom-style : none;
    border-bottom-width : medium;
    border-collapse : separate;
    border-image : none;
    border-left : 0;
    border-left-color : inherit;
    border-left-style : none;
    border-left-width : medium;
    border-radius : 0;
    border-right : 0;
    border-right-color : inherit;
    border-right-style : none;
    border-right-width : medium;
    border-spacing : 0;
    border-top : 0;
    border-top-color : inherit;
    border-top-left-radius : 0;
    border-top-right-radius : 0;
    border-top-style : none;
    border-top-width : medium;
    bottom : auto;
    box-shadow : none;
    box-sizing : content-box;
    caption-side : top;
    clear : none;
    clip : auto;
    color : inherit;
    columns : auto;
    column-count : auto;
    column-fill : balance;
    column-gap : normal;
    column-rule : medium none currentColor;
    column-rule-color : currentColor;
    column-rule-style : none;
    column-rule-width : none;
    column-span : 1;
    column-width : auto;
    content : normal;
    counter-increment : none;
    counter-reset : none;
    cursor : auto;
    direction : ltr;
    display : inline;
    empty-cells : show;
    float : none;
    font : normal;
    font-family : inherit;
    font-size : medium;
    font-style : normal;
    font-variant : normal;
    font-weight : normal;
    height : auto;
    hyphens : none;
    left : auto;
    letter-spacing : normal;
    line-height : normal;
    list-style : none;
    list-style-image : none;
    list-style-position : outside;
    list-style-type : disc;
    margin : 0;
    margin-bottom : 0;
    margin-left : 0;
    margin-right : 0;
    margin-top : 0;
    max-height : none;
    max-width : none;
    min-height : 0;
    min-width : 0;
    opacity : 1;
    orphans : 0;
    outline : 0;
    outline-color : invert;
    outline-style : none;
    outline-width : medium;
    overflow : visible;
    overflow-x : visible;
    overflow-y : visible;
    padding : 0;
    padding-bottom : 0;
    padding-left : 0;
    padding-right : 0;
    padding-top : 0;
    page-break-after : auto;
    page-break-before : auto;
    page-break-inside : auto;
    perspective : none;
    perspective-origin : 50% 50%;
    position : static;
    /* May need to alter quotes for different locales (e.g fr) */
    quotes : '\201C' '\201D' '\2018' '\2019';
    right : auto;
    tab-size : 8;
    table-layout : auto;
    text-align : inherit;
    text-align-last : auto;
    text-decoration : none;
    text-decoration-color : inherit;
    text-decoration-line : none;
    text-decoration-style : solid;
    text-indent : 0;
    text-shadow : none;
    text-transform : none;
    top : auto;
    transform : none;
    transform-style : flat;
    transition : none;
    transition-delay : 0s;
    transition-duration : 0s;
    transition-property : none;
    transition-timing-function : ease;
    unicode-bidi : normal;
    vertical-align : baseline;
    visibility : visible;
    white-space : normal;
    widows : 0;
    width : auto;
    word-spacing : normal;
    z-index : auto;
    /* basic modern patch */
    all: initial;
    all: unset;
}

/* basic modern patch */

#reset-this-root {
    all: initial;
    * {
        all: unset;
    }
}

Relevent github repo with a december 2017 more exaustive list
Related
Related from MDN
Related W3C specs

As mentioned in a comment by @user566245 :

this is correct in principle, but individual mileage may vary. For
example certain elements like textarea by default have a border,
applying this reset will render those textarea's border less.

JAVASCRIPT ?

Nobody thought about other than css to reset css? Yes?

There is that snip fully relevant : https://stackoverflow.com/a/14791113/845310

getElementsByTagName("*") will return all elements from DOM. Then you
may set styles for each element in the collection:

answered Feb 9 '13 at 20:15 by VisioN

var allElements = document.getElementsByTagName("*");
for (var i = 0, len = allElements.length; i < len; i++) {
    var element = allElements[i];
    // element.style.border = ...
}

With all this said; i don't think a css reset is something feasable unless we end up with only one web browser .. if the 'default' is set by browser in the end.

For comparison, here is Firefox 40.0 values list for a
<blockquote style="all: unset;font-style: oblique"> where font-style: oblique triggers DOM operation.

align-content: unset;
align-items: unset;
align-self: unset;
animation: unset;
appearance: unset;
backface-visibility: unset;
background-blend-mode: unset;
background: unset;
binding: unset;
block-size: unset;
border-block-end: unset;
border-block-start: unset;
border-collapse: unset;
border-inline-end: unset;
border-inline-start: unset;
border-radius: unset;
border-spacing: unset;
border: unset;
bottom: unset;
box-align: unset;
box-decoration-break: unset;
box-direction: unset;
box-flex: unset;
box-ordinal-group: unset;
box-orient: unset;
box-pack: unset;
box-shadow: unset;
box-sizing: unset;
caption-side: unset;
clear: unset;
clip-path: unset;
clip-rule: unset;
clip: unset;
color-adjust: unset;
color-interpolation-filters: unset;
color-interpolation: unset;
color: unset;
column-fill: unset;
column-gap: unset;
column-rule: unset;
columns: unset;
content: unset;
control-character-visibility: unset;
counter-increment: unset;
counter-reset: unset;
cursor: unset;
display: unset;
dominant-baseline: unset;
empty-cells: unset;
fill-opacity: unset;
fill-rule: unset;
fill: unset;
filter: unset;
flex-flow: unset;
flex: unset;
float-edge: unset;
float: unset;
flood-color: unset;
flood-opacity: unset;
font-family: unset;
font-feature-settings: unset;
font-kerning: unset;
font-language-override: unset;
font-size-adjust: unset;
font-size: unset;
font-stretch: unset;
font-style: oblique;
font-synthesis: unset;
font-variant: unset;
font-weight: unset;
font: ;
force-broken-image-icon: unset;
height: unset;
hyphens: unset;
image-orientation: unset;
image-region: unset;
image-rendering: unset;
ime-mode: unset;
inline-size: unset;
isolation: unset;
justify-content: unset;
justify-items: unset;
justify-self: unset;
left: unset;
letter-spacing: unset;
lighting-color: unset;
line-height: unset;
list-style: unset;
margin-block-end: unset;
margin-block-start: unset;
margin-inline-end: unset;
margin-inline-start: unset;
margin: unset;
marker-offset: unset;
marker: unset;
mask-type: unset;
mask: unset;
max-block-size: unset;
max-height: unset;
max-inline-size: unset;
max-width: unset;
min-block-size: unset;
min-height: unset;
min-inline-size: unset;
min-width: unset;
mix-blend-mode: unset;
object-fit: unset;
object-position: unset;
offset-block-end: unset;
offset-block-start: unset;
offset-inline-end: unset;
offset-inline-start: unset;
opacity: unset;
order: unset;
orient: unset;
outline-offset: unset;
outline-radius: unset;
outline: unset;
overflow: unset;
padding-block-end: unset;
padding-block-start: unset;
padding-inline-end: unset;
padding-inline-start: unset;
padding: unset;
page-break-after: unset;
page-break-before: unset;
page-break-inside: unset;
paint-order: unset;
perspective-origin: unset;
perspective: unset;
pointer-events: unset;
position: unset;
quotes: unset;
resize: unset;
right: unset;
ruby-align: unset;
ruby-position: unset;
scroll-behavior: unset;
scroll-snap-coordinate: unset;
scroll-snap-destination: unset;
scroll-snap-points-x: unset;
scroll-snap-points-y: unset;
scroll-snap-type: unset;
shape-rendering: unset;
stack-sizing: unset;
stop-color: unset;
stop-opacity: unset;
stroke-dasharray: unset;
stroke-dashoffset: unset;
stroke-linecap: unset;
stroke-linejoin: unset;
stroke-miterlimit: unset;
stroke-opacity: unset;
stroke-width: unset;
stroke: unset;
tab-size: unset;
table-layout: unset;
text-align-last: unset;
text-align: unset;
text-anchor: unset;
text-combine-upright: unset;
text-decoration: unset;
text-emphasis-position: unset;
text-emphasis: unset;
text-indent: unset;
text-orientation: unset;
text-overflow: unset;
text-rendering: unset;
text-shadow: unset;
text-size-adjust: unset;
text-transform: unset;
top: unset;
transform-origin: unset;
transform-style: unset;
transform: unset;
transition: unset;
user-focus: unset;
user-input: unset;
user-modify: unset;
user-select: unset;
vector-effect: unset;
vertical-align: unset;
visibility: unset;
white-space: unset;
width: unset;
will-change: unset;
window-dragging: unset;
word-break: unset;
word-spacing: unset;
word-wrap: unset;
writing-mode: unset;
z-index: unset;

Why Doesn't This CSS :Not() Declaration Filter Down