Do CSS / HTML children override parents? - html

Given the following code:
<div id="bla">
<p class="blubber">Johnny Bananas</p>
</div>
and the style in head of that html doc:
<style>
div#bla{background:yellow}
p.blubber{background:purple}
</style>
Why is it that the child will be coloured purple and overlay its parent?

The background property is not inherited by children by default. Therefore, the background style of div#bla does not apply to p.blubber, and p.blubber can specify its own background color independently of its parent and regardless of specificity.
And since background isn't being inherited, no overriding actually takes place.

When multiple style sheets are used, the style sheets may fight over control of a particular selector. In these situations, there must be rules as to which style sheet's rule will win out. The following characteristics will determine the outcome of contradictory style sheets.
check out the section on cascading order - http://htmlhelp.com/reference/css/structure.html

Because the specificity is the same, so the rule will apply to the p element. If you remove the p and just have .blubber, it wouldn't work.
Also, children can't override parents, so if there were more content, you'd see yellow around the p (add padding to the div).
Background color is not and inherited attribute in CSS.

Related

different css on same element by id, class etc

There is one <p> tag with class .eleclass and id #eleid and i have specified 3 css to the <p> tag one specified with class second with id and third with just p declared.
p#eleid{
color:yellow;
}
p.eleclass{
color:blue;
}
p{
color:red;
}
<p id="eleid" class="eleclass">
hello para.
</p>
Now i wonder why the rule applied to p#eleid is working when css runs from top to bottom nature and at bottom color red is specified so <p> should be red in color.
Is there any css rules hidden behind it??
This problem inclues use of id not only class.
It comes down to CSS specificity.
From MDN:
Specificity is the means by which browsers decide which CSS property values are the most relevant to an element and, therefore, will be applied.
As it happens, an ID based selector has higher priority than a tag based selector. This is because an ID is more specific than a tag. In other words, the tag selector applies to all p elements, while the ID will only apply to the p with the ID.
There are ways around specificity, such as the !important keyword - however, I mostly recommend against working around specificity, as it can lead to bugs.

!important overriden by a class of child element

I have a very bad CSS rule (high specifity, use of !important) which sets color of text in a paragraph:
#wrapper .article .text {
color: green !important;
}
Then I put a simple span element in that paragraph and set color of the span text via simple class:
.black {
font-weight: bold;
color: black;
}
How come, that this simple class with low specifity and no !important flag overrides the parent rule?
Full snippet on codepen.io here: http://codepen.io/Jarino/pen/oXYeQZ?editors=110
This is simply because there is no more specific rule for that <span> than what you have declared in .black. Even though it is a child element of the <p> that has an important! flagged rule, it only inherits the color from it if it can find no more specific other color definition. Inheritance from a parent context is the least specific "rule" possible. Also, the !important part of a rule is not inherited, afaik.
If this were not the case, you would be very commonly forced to either use !importantwhenever an element takes a style that it already inherited from the parent, or you would have to constantly use very long selectors to make sure your child element selector does not have a lower specificity than the definition it inherits.
Also, compare what Mozilla says on the subject:
Styles for a directly targeted element will always take precedence
over inherited styles, regardless of the specificity of the inherited
rule.
https://developer.mozilla.org/en-US/docs/Web/CSS/Specificity#directly-targeted-elements
The high-specificity rule applies only to the parent class. When it comes to it's children, the high-specificity of the parent class mellows down to a parent style that is inherited by the child.
And, when it comes to styling the child, all CSS rules specifically targeting it get precedence over the high-specificity rule of the parent.
If you do 'Inspect Element' for this child span tag in the Developer Console of your browser, you'll see how preference is given to CSS rules targeting that particular element that overrides all the parent styling that appears way down the list.
if you don't want your .black class to override the parent rule you can simply remove the color property from your .black class, the class mentioned in span will always have high specificity regardless of parent rule.
Because !important applies only for current element style not for child elements with specified same property.
How come, that this simple class with low specifity and no !important
flag overrides the parent rule?
Well, because they are two different rules.
You have your text class which is pretty strictly called but only a class without selector.
After you addded a span with a different class it will not be overwritten, because it's another rule. It gets applied to the span. And .text get applied to the paragraph.

CSS style does not apply, style depth limit?

I have the following problem:
I get a generated HTML with dynamic content. The IDs and the html tag-hierarchy is always the same. I can set a stylesheet.
I tried to set the color of the text to red. If I set it on this position where it's done in the screenshot it does not work. If I set it inline in the table below (table cols=2 border=0...) it works.
Is there a depth limit for CSS ? How can I set the color for the whole text containing the div (id=15B_gr or id=oReportCell) ?
++UPDATE++
I tried to set a stylesheet, but it does not work:
You should be able to target all the children of a div by using an asterisk. In this case:
#15B_gr * {
color:red;
}
or you could set it on just the elements:
#15B_gr span {
color:red;
}
** Edit for further information **
As pointed out by #nico o, some complications can arise due to having a number as the first character in the ID. Previous versions of the HTML spec did not allow IDs to begin with a number.
http://w3c.github.io/html-reference/datatypes.html#common.data.id
Maybe you have a rule (in another stylesheet?) which has a selector which has the elements class that you want to style but additionally the class name of an element of a parent or grandparent element. In this case that specific style would outweight your style.
In this case you could add an "!important" to your rule (color: red !important; ) ...
or you could add the selectors of the other stylesheets style to yours too so that that style doesn't outweight your's anymore.
You should "inspect" the element! (Rightclick on it, "inspect element") to find the active and overwritten rules for that specific element! You find those info in the lower right corner of the "inspector"-Window wich then opens. Along with the currently active styles you there find the stylesheet in which the styles are defined.

CSS3 :not() selector, working around contained elements

I am moving clarification to the top of this post: When the mouse is not hovering over a certain div, I want elements other than this div to have a red background-color. Can this be achieved with a not() selector as seen in this post? The predicament appears to be that since the certain div is within a body element, the mouse will always be hovering over the body element even when it's over the certain div, thus the body will always have a red background-color.
I am trying to use the not() selector to affect elements when hovering over elements that are not within my selection.
For example:
[data-panel] { background-color:white; }
:not([data-panel=visible]):hover { background-color:red; }
<body>
<div data-panel='visible'>
<div data-panel='visible'>Content</div>
</div>
</body>
My desired outcome is that if the mouse is hovering anywhere besides those divs, the background-color will change to red (i.e. hovering in the body).
However, since those divs are within the body, that selector will always be active. The body will always be red. Is there anyway to style those divs so that this doesn't happen? Maybe something with z-index? Any clues?
What you are trying to do is not possible with CSS alone.
To achieve that effect – let the body turn red on :hover, but not when hovering the panels – you have to cancel the pointer event bubbling on the panels. This is only possible using JS.
BTW, HTML5 has a method to define own attributes: the data-* attributes; e.g. data-panel="visible".
Don't quote your attribute selector.
As already mentioned by James; panel is not a valid HTML5 attribute. You should be taking advantage of HTML5's data-* attributes.
:not([data-panel=visible]):hover {
background-color:red;
}
<div data-panel='visible'>
<div data-panel='visible'>Content</div>
</div>
This of course, affects all elements that don't have the matching attribute, including <body>, which is while your entire page's background will turn red when hovered.
Edit
The predicament appears to be that since the certain div is within a body element, the mouse will always be hovering over the body element even when it's over the certain div, thus the body will always have a red background-color
There is no CSS parent selector, so an event on an element within the body, can't have any say over any styles applied to the body.

Is there any kind of HTML or CSS that ensures HTML within a DIV doesn't inherit any styling?

I am currently restyling a website, but part of the site takes a string from the CMS and puts it into a description area. The description often has its on HTML, such as bullet points.
The problem is the designs we received also use bullet points to style certain aspects, which make everything within this description area styled entirely incorrectly (tiny width for ULs, background applied to H2, etc).
Is there any kind of tag that will reset the styling of everything within it?
Thanks in advance.
Edit: I've gone for this solution, which works when I apply the class 'CMSReset'. It resets the main offenders, thanks for the help:
div.CMSReset, div.CMSReset *
{
margin:0pt !important;
padding:0pt !important;
vertical-align:baseline !important;
width:auto !important;
background:none;
color:inherit;
}
short and simple: no, you'll have to reset the stylings taht need to be reseted on your own.
a workaround would be to use an iframe wich would prevent the inner content against inherited styles, but that solution is even worse in my opinion.
this other topics might also be interesting for you:
reset multiple css styles for one single div element
how to not inherit? or how to reset inherited width to the value before? (css)
Generally, people override CSS Styles in 2 ways:
1) They define an inline style on the attribute itself so:
<div style="background-color:#FFFFFF"></div>
Would override any other style.
You can also apply a style via an id (#IdName) which will have precedence
2) They redefine the style at that level of the document. You can use the !important css modifier (but this isn't universally supported).
If you've blanket applied styles, like div or body > div then these can be difficult to override and often require restructuring, or rethinking, your styles and classes.