Collapsible
Reveal supporting details without leaving the page.
use blinc_cn as cn;
use blinc_core::reactive::Signal;
use blinc_layout::prelude::*;
pub fn collapsible_demo(confirmed: Signal<bool>) -> Div {
div()
.class("demo-stack")
.child(cn::collapsible_section("Project details", confirmed, || {
div()
.class("demo-collapsible-copy")
.child(text("Design, build and ship with a shared language."))
}))
}
@layer components {
.cn-collapsible-trigger:focus-visible {
outline: 2px solid var(--focus-ring);
outline-offset: 2px;
}
.cn-chevron {
transition: transform var(--duration-normal) var(--ease-state);
}
.cn-collapsible-trigger[data-state="open"] > .cn-chevron {
transform: rotate(180deg);
}
.cn-collapsible-content {
overflow: hidden;
}
.cn-collapsible-content[data-state="closed"] {
height: 0;
}
.cn-collapsible-section {
border: 1px solid var(--border);
border-radius: var(--radius-md);
}
.cn-collapsible-trigger {
cursor: pointer;
color: var(--text-primary);
border-radius: var(--radius-md);
transition: background-color var(--duration-fast) var(--ease-state);
}
.cn-collapsible-trigger:hover,
.cn-collapsible-trigger:active {
background: color-mix(in srgb, var(--surface-elevated) 50%, transparent);
}
.cn-collapsible-trigger > .cn-chevron {
color: var(--text-secondary);
}
}
Usage and properties
Reveal supporting details without leaving the page. Apply CSS after the component layer to restyle the documented parts.
Use the installation guide to add blinc_cn and its component stylesheet. Create the fixture bindings once, and return the demo from your UI builder. Values marked Bound accept Signal/Computed sources where the API supports them; structural options configure the component at construction.
| Property | Type | Update model | This example |
|---|---|---|---|
open | Signal<bool> | Bound | values.confirmed |
trigger / content | builders | Construction | Show details |
Keyboard and interaction
Tab reaches the trigger; Enter or Space opens or closes the content. :focus-visible marks keyboard focus.
Customizing it
Add application CSS after the default component layer. These selectors are the restyling surface for this component:
.cn-collapsible.cn-collapsible-content.cn-collapsible-trigger.cn-chevron.cn-collapsible-section.demo-collapsible-copy
Theme and component variables: --primary, --text-primary, --text-secondary, --surface, --border, --radius-default, --duration-fast, --ease-state.
Built-in themes
The Live theme control installs Blinc's own theme bundles, including their colours, focus rings, corner shapes and motion tokens.
pub fn theme_bundle_for(name: &str) -> blinc_theme::ThemeBundle {
match name {
"restrained" => blinc_theme::RestrainedTheme::bundle(),
"expressive" => blinc_theme::ExpressiveTheme::bundle(),
_ => blinc_theme::HybridTheme::bundle(),
}
.with_css(blinc_cn::cn_styles::CN_STYLES)
}Download the default widget and component stylesheets. Sample assets and licenses are available in the asset guide.
Documentation
From the canonical component guide.
Pass a Signal<bool> to both the trigger and content:
let open = ctx.use_signal(false);
div().flex_col()
.child(CollapsibleTrigger::new("Show details", open))
.child(collapsible(open).content(|| {
div().child(text("Details remain mounted while this section folds."))
}))
Writing open.set(true) from an event or application callback opens the same
section. collapsible_section combines the trigger and body:
let open = ctx.use_signal(false);
collapsible_section("Details", open, || {
div().child(text("Additional information"))
})
There are no separate collapsible_trigger() or collapsible_content()
functions. The parts are .cn-collapsible-trigger, .cn-collapsible-content
and .cn-chevron; their data-state is open or closed. CSS sets the
closed height and chevron transform, with theme-timed expansion.
Platforms and version
The component API is available in Blinc 0.6.0. The Live example runs in a dedicated worker and requires a compatible GPU surface. Preview and Code remain available when Live cannot start. The canvas has a descriptive label; a full screen-reader DOM mirror is not provided. The gallery integration is based on revision e2e55c24e078.
Recordings and live demos use the default Hybrid theme with bundled Noto Sans. The recording uses a 560 × 320 logical viewport at twice that resolution. Live follows its container and actual display density. Source base revision · Exact build source · Artifact versions and checksums · Font license.