spark_css 1.0.0-alpha.3

Type-safe CSS style system for Spark framework.

Spark CSS

A type-safe CSS style system for the Spark framework.

spark_css provides a comprehensive set of typed CSS value classes and a stylesheet API for building CSS in Dart. Instead of working with raw strings, you use typed constructors like CssColor.hex(), CssLength.rem(), and CssDisplay.flex that guarantee valid CSS output at compile time.

Features

• Type-Safe CSS Values: Sealed classes for colors, lengths, spacing, display, position, flexbox, typography, borders, transitions, and more.
• Stylesheet API: Style.typed for individual rule sets and css() helper for multi-selector stylesheets.
• CSS Shorthand Support: CssSpacing handles 1, 2, 3, or 4 value shorthand for margin and padding.
• CSS Functions: Support for calc(), min(), max(), clamp(), and fit-content().
• CSS Variables: Every value type supports variable() for CSS custom properties.
• Automatic Minification: CSS output is minified in production builds via the dart.vm.product flag.
• Escape Hatches: raw() factories and .add() method for properties not yet covered by typed constructors.
• Zero Dependencies: Pure Dart package with no runtime dependencies.

Installation

dart pub add spark_css

Usage

Import the package:

import 'package:spark_css/spark_css.dart';

Creating a Style

Use Style.typed to build a type-safe set of CSS properties:

final style = Style.typed(
  display: CssDisplay.flex,
  padding: CssSpacing.all(CssLength.px(16)),
  backgroundColor: CssColor.hex('f5f5f5'),
  borderRadius: CssLength.px(8),
);

print(style.toCss());
// background-color: #f5f5f5;
// border-radius: 8px;
// display: flex;
// padding: 16px;

Creating a Stylesheet

Use the css() helper to map selectors to styles:

final styles = css({
  ':host': Style.typed(
    display: CssDisplay.flex,
    flexDirection: CssFlexDirection.column,
    gap: CssLength.rem(1),
  ),
  ':host(.large)': Style.typed(
    padding: CssSpacing.all(CssLength.px(24)),
  ),
});

print(styles.toCss());

Spacing Shorthand

CssSpacing mirrors CSS shorthand conventions:

// Single value (all sides)
padding: CssSpacing.all(CssLength.px(16)),

// Two values (vertical | horizontal)
margin: CssSpacing.symmetric(CssLength.px(10), CssLength.px(20)),

// Four values (top | right | bottom | left)
margin: CssSpacing.trbl(
  CssLength.px(10),
  CssLength.px(20),
  CssLength.px(30),
  CssLength.px(40),
),

CSS Variables

Every value type supports CSS custom properties:

Style.typed(
  color: CssColor.variable('text-primary'),
  fontSize: CssLength.variable('font-size-base'),
)

Custom Properties

For properties not covered by the typed constructors, use .add():

final style = Style.typed(
  display: CssDisplay.grid,
);
style.add('grid-template-columns', 'repeat(3, 1fr)');

Contributing

This package is part of the Spark framework. Contributions are welcome at https://github.com/KLEAK-Development/spark.