The * selector in react/next.js - css

I am currently working on my first website in react. In my main.module.css I have
* {
padding: 0;
margin: 0;
box-sizing: border-box;
}
Just typical css styling reset. But React returns the error:
Syntax error: Selector "*" is not pure (pure selectors must contain at least one local class or id)
Do you have any solution for that? I want to keep this styling reset instead of adding those three lines to every element i have.

You should not have styling reset in module.css file.
Move this css reset to normal css file like index.css file.
Styling file with .module.css extensions are used to define the styling you can say local to a components. It means that if you import a module.css file in two different components, both components will have same styles with different class names. This one prevents overriding of styles.

That would go into global styles, which can be done by simply adding:
require('./name-of-your-global-style.css');

Related

Can I disable vaadin flow theeming and apply ordinary css

Vaadin flow theming and styles confuse me. Is there a way to disable it and apply natural css. I know how to reference a css file inside vaadin, and use setClassName but I would prefer to use ordinary css style for components.
Thank you
You can override the default lumo styling by providing yours. For instance, to remove the background color from a ComboBox, I can target the input as follows in a CSS file named vaadin-combo-box.css:
[part="input-field"] {
background-color: var(--lumo-base-color);
max-width: fit-content;
}
To set the colors for a disabled button, you can target it as follows:
filename: vaadin-button.css
code:
:host([theme~='primary'][disabled]) {
background-color: red;
}
And you get the following:
To change the primary color or any other global styling, explore your styles.css file.
For a better understanding, take a look at this video https://vaadin.com/learn/training/v14-theming
Like with all other styling you need to check the states / attributes of the component while the specific state is active and check the DOM - only caveat would be that you need to add those style in the specific files like vaadin-button.css to be applied inside the shadow DOM.

Angular material overwrite style.css

I'm trying to change the padding on mat-cell and I've noticed some weird behavior.
If I write the css inside the component's css file everything works just fine, but if I write it in style.css (I want to apply it to the whole app) it gets overwritten by the default.
I guess this has to do with the order in which the css files are applied. If that is the case, how can I see this order and is there a way to change it or bring style.css on top?
I would suggest to create a separate .scss file reserved for styling globaly Angular Material elements, and importing it in the main styles.scss file.
Answering your question - propably you're not 'specific' enough. First of all it would be nice to add an additional custom class to your Material element so the custom styles will be applied only when this class is present. Example on styling
.mat-table.my-custom-class {
width: 100%;
.mat-cell {
font-size: 20px;
padding: 20px;
}
}
You might nest the elements event more for higher css specificity
That works for me:
.mat-cell {
padding: 12px!important;
}
Check for the parent scope of default style which is overriding css added in style.css using developer tool. Use the same parental scope along with !important.

React js css stylesheet applied to more than one component

I have a Parent.js component with a child component Child.js inside of it.
Parent.js imports parents.css
Child.js imports child.css
If I define this in child.css:
.example {
font-family: 'Roboto', sans-serif;
}
How come I'm able to use this className in the Parent.js component as well despite not specifying it in the parent.css?
Unless you use unique class names, CSS Modules or some other alternatives available for scoping CSS styles to any component in React, styles specified in any CSS file will be applied globally.
If you want to limit styles to any component, use CSS Modules or make sure every class name is unique in your project.
For details on how to use CSS Modules, see Adding a CSS Modules Stylesheet. You can also look at 9 Ways To Implement CSS in React JS for other available alternatives.
I recommend using unique class names. For example, lets say you have multiple ListView components: MemberUsersListView, AdminUsersListView, TestUsersListView; and each of them needs to be styled differently. I would create the following CSS classes:
.MUListView{
...
}
.AUListView{
...
}
.TUListView{
...
}
I know this seem's annoying, but it's cleaner than applying inline styles and easier to implement on smaller projects.

How to remove the particular scss if the component get destroyed?

I am using PrimeNG for my project I used p-dropdown with appendTo body only for particular components files, and I changed the css in only one file as follow, for example
geneFinder.component.scss
.ui-dropdown-panel {
z-index: 999 !important;
}
and component file is
<p-dropdown [options]="geneoptions" formControlName="gene" appendTo="body"></p-dropdown>
But this css is affecting in all other files also. If I removed the !important it is not affecting in other pages and this is not working with particular component itself. How to fix this issue.?
you can try this
<p-dropdown [options]="geneoptions" formControlName="gene" appendTo="body" [style]={'z-index':'999 !important'}></p-dropdown>
You can also customize the z-index with the p-dropdown attribute baseZIndex. This way, you don't need to set it in css, and it affects only the dropdown where the attribute is set.
Angular is a single page application framework hence all the CSS would be combined and CSS styles will be created inside style tag of the single html page. If we are having a CSS class with name that is common to other component's elements it does affects it.
In case of component specific CSS, create a custom class name something like,
.mycomponent-ui-dropdown-panel {
z-index: 999 !important;
}
and add the class to the element of the component's html where we need this change to be applied. This will make sure that other elements of other components are not affected by the CSS style.
I fixed the issue by adding the panelStyleClass in my component,
<p-dropdown [options]="geneoptions" formControlName="gene" appendTo="body" panelStyleClass="overlay-zindex"></p-dropdown>
.overlay-zindex{
z-index: 999 !important;
}

Overriding the encapsulated CSS of external component

I was wondering how to override the encapsulated CSS of an external component.
So I am using material2 in my project and the tabs component has a the attribute overflow set on tab-body. Is it possible to override the overflow value?
You can use the special css /deep/ instruction. See the documentation
So, if you have
app
sub-component
target-component
<div class="target-class">...</div>
You can put in your apps css (or less):
/deep/ .target-class {
width: 20px;
background: #ff0000;
}
Obviously, you can put this css fragment in sub-component as well.
From this article
Although the style of a component is well isolated, it can still be easily overridden if necessary. For that, we just need to add an attribute to the body of the page:
<body override>
<app></app>
</body>
The name of the attribute can be anything. No value is needed and the name override makes it apparent what its being used for. To override component styles, we can then do the following:
[override] hello-world h1 {
color:red;
}
Where override is the attribute, hello-world is the target component, and h1 is whatever you are trying to restyle. (get this right or it wont work).
Your component hello-world would be
selector: 'hello-world',
styles: [`
h1 {
color: blue;
}
`],
template: ` <h1>Hello world</h1> `
I think this is the most elegant way.
Alternatively if you are building a library of some sort, you can reset the styling altogether by doing something fancy in your css like:
:host-context(.custom-styles) {
//.. css here will only apply when there is a css class custom-styles in any parent elem
}
So then to use your component you'd use
<hello-world class="custom-styles">
But this is way less convenient than the first option.
::ng-deep .tag-or-css-class-you-want-to-override {
/* Add your custom css property value. */
}
The syntax ::ng-deep is used to override outside css class or tags without using ViewEncapsulation.None.
I see variations of this question a lot and since this is the top question on the subject I want to give the simplest answer. ng-deep and similar functionality is deprecated, so it's best to just rely on vanilla CSS.
Simply create a CSS selector with a higher specificity.
Most people (including myself) get hung up trying to do that because they don't understand two things:
Angular View Encapsulation
CSS Specificity
Angular View Encapsulation
View Encapsulation ensures CSS within a component only affects that component. To affect other components, you need some global CSS. You can do this by using a global style file like styles.css or by disabling View Encapsulation on a component.
#Component({
...
encapsulation: ViewEncapsulation.None
})
CSS Specificity
When two selectors select the same element, the CSS that actually gets applied is based on specificity: https://developer.mozilla.org/en-US/docs/Web/CSS/Specificity
You can increase specificity by simply adding more elements to your CSS selector. For example p.className is more specific than just .className. If you're lazy, you can just repeat a class name to increase specificity. .className.className is more specific than .className.
So to override any CSS in an Angular project, go into styles.css and repeat the class selector until your CSS has a higher specificity than the original.
.className.className.className {
color: red;
}
Didn't work? Add another .className.
Just check the class that is being applied to the tabs by the external component (use Inspector or any other tool). In your style css file, add the same name of the class for the tabs and set the overflow property along with adding !important to it to make sure it overwrites the previous one. Also make sure your css link to the page is added after the external component css link if any.
Hope this helps.
::ng-deep .css-class-you-want-to-override{
/*your custom css property value. like below */
background: white !important;
}

Resources