Concorde guide — Adding styles. No style crosses the shadow root of a component, except for inheritable properties (which have the "inherit" property possible) and CSS variables. Doc ID: docs/_getting-started/theming. Keywords: Concorde, supersoniks, docs/_getting-started/theming, theming, Adding styles, guide, , size, {reflect: true}, :host(), :host([type='primary']){...}, inline, block, display, contents. URL: https://concorde.supersoniks.org/crawl/docs/_getting-started/theming.html.

Adding styles

Normal Behavior

No style crosses the shadow root of a component, except for inheritable properties (which have the "inherit" property possible) and CSS variables. Properties integrated via a "slot" remain stylizable in a conventional way.

• During creation / from the inside:
  • We edit the static "styles" property of the lit component, which can also reference shared and dynamic styles. These styles are scoped and do not impact the outside.
  • We use CSS variables as the value of properties intended to be customized from the outside. For each variable, we define a default value to have a simple but consistent base style.
  • We only rewrite inheritable properties with hard values if they are truly specific to the component.
  • The <style> tag as a direct child can be used as a last resort, especially if there is a need for particularly dynamic customization. Performance is reduced.
• During use / from the outside: We define values for inheritable CSS properties (e.g., font-_, color...) using tools like Tailwind. We modify the value of CSS variables used by the component.

Choosing Style Presets via Reactive Properties:

The declaration of reactive properties is useful for selecting a particular configuration that mostly affects a set of properties.

For example, a size property (xs, sm, md, xl) will affect margins, font, line heights to align them with the corresponding CSS vars, which can be customized using the methods mentioned earlier if necessary.

It is recommended to use the {reflect: true} property for reactive properties that have an associated style on the :host(). For example: :host([type='primary']){...}

☢️ Caution: Passing class names via reactive properties / HTML attributes of the component should be avoided as it can quickly lead to difficult-to-manage situations.

CSS "display" Property

By default, the display property is inline. Therefore, be careful to define it according to the needs, as one might mistakenly expect it to be block as with a regular <div>.

☢️ Caution: Defining the display property as contents may seem attractive at first, but:

• It almost always leads to the creation of wrappers to style the content (instead of using :host).
• It is no longer possible to directly add classes to the component or style it from the outside. Ultimately, the amount of code to write increases significantly.

TAILWIND Functional Classes

tailwind has been integrated into Concorde and is available in scoped components (with Shadow DOM). To use it, you need to import the following:

import { tailwind } from "@supersoniks/concorde/la-billetterie/ui/theme/theme";

Then include the tailwind style in the static styles property of the component:

static styles = [tailwind];

Finally, use it in the HTML within the render function:

<p class="m-2">A paragraph with margin</p>

The colors from Concorde's theme are referenced in Tailwind's theme.

Operation without Shadow DOM

Usefulness

This operation is particularly useful when it comes to adding behavior to a simple existing element. It may also become necessary to establish compatibility with a traditional JS library.

For example, with a text input:

• Trigger automatic data or filter update when typing text.
• Automatic formatting.
• Constraints that cannot be handled by native methods.

Consequences

If there is no shadow DOM (see the noShadowDom property of Subscriber):

• Styling using the static "styles" property of the lit component will not be applied.
• The element and its content can be styled in a traditional manner.

For example, the components queue, list, and fetch do not have a shadow DOM.

ℹ️ Note: Specifically in this case, it may be useful to set the display property to contents.