u

package
v4.2.0 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Jul 5, 2026 License: MIT Imports: 3 Imported by: 0

Documentation

Overview

Package u is the Tailwind-shaped typed utility engine layered over the css Layer-1 foundation. Every utility is a typed Go symbol (no class-string parser), so the whole surface is autocompletable and compile-checked. Each utility resolves its argument against the active css.Theme and returns Layer-1 css.Rule(s); emission, dedup, and SSR reuse the Layer-1 registry/sink unchanged.

This is the curated core (spacing/color/type/flex/border/effects + the responsive/state variants). The design's full-parity surface is generated from a spec table over the theme; the core lands first and the long tail is incremental table entries.

Index

Constants

View Source 
const (
	ShadowNone = css.ShadowNone
	ShadowSm   = css.ShadowSm
	ShadowMd   = css.ShadowMd
	ShadowLg   = css.ShadowLg
	ShadowXl   = css.ShadowXl
	Shadow2xl  = css.Shadow2xl

	PropAll       = css.PropAll
	PropColors    = css.PropColors
	PropOpacity   = css.PropOpacity
	PropTransform = css.PropTransform
	PropShadow    = css.PropShadow

	Linear    = css.Linear
	Ease      = css.Ease
	EaseIn    = css.EaseIn
	EaseOut   = css.EaseOut
	EaseInOut = css.EaseInOut
)
View Source 
const (
	White    = css.White
	Black    = css.Black
	Slate100 = css.Slate100
	Slate500 = css.Slate500
	Slate800 = css.Slate800
	Slate900 = css.Slate900
	Sky500   = css.Sky500
	Red500   = css.Red500
)

Color tokens re-exported for ergonomic u.Slate900 style call sites.

Variables

View Source 
var (
	Class         = css.Class
	New           = css.New
	Rules         = css.Rules
	DefineUtility = css.DefineUtility
	Utility       = css.Utility
	DefineVariant = css.DefineVariant
	UseTheme      = css.UseTheme
	DefaultTheme  = css.DefaultTheme
	Reset         = css.Reset
	Harvest       = css.Harvest // available on both build lanes
	Seed          = css.Seed
	SetSink       = css.SetSink
	MarkImportant = css.MarkImportant
)
View Source 
var (
	Px        = css.Px // length: Px(8) -> "8px"
	Rem       = css.Rem
	Ems       = css.Ems
	Percent   = css.Percent
	Vh        = css.Vh
	Vw        = css.Vw
	RawLength = css.RawLength
	Num       = css.Num
	Ms        = css.Ms
	S         = css.S
	Deg       = css.Deg
	Turn      = css.Turn
	Hex       = css.Hex
	RGB       = css.RGB
	RGBA      = css.RGBA
	CSSVar    = css.Var
	FontSize  = css.FontSize
	MinWidth  = css.MinWidth
	MaxWidth  = css.MaxWidth
	MinHeight = css.MinHeight
	MaxHeight = css.MaxHeight
)
View Source 
var (
	Raw = css.Raw
	Sel = css.Sel
)

Raw and Sel are the documented escape hatches for the typed utility surface. The curated utilities cover the common surface, not every CSS property; when none fits, drop to a raw declaration rather than reaching outside the engine. Raw(property, value) emits one declaration and Sel(selector, rules...) emits an arbitrary selector — both fold, dedup, content-hash, and emit through the SAME Layer-1 registry/sink as every typed utility, so a raw style still gets a stable class name and SSR reuse (it is not an unmanaged inline style). Reach for these only for the long tail; prefer a typed utility whenever one exists so the style stays autocompletable and compile-checked. 

// no typed aspect-ratio utility → use the raw escape hatch, still registry-managed:
css.New(u.Pad(u.Spacing4), u.Raw("aspect-ratio", "16 / 9"))
View Source 
var (
	Media        = css.Media
	MinW         = css.MinW
	MaxW         = css.MaxW
	RawMedia     = css.RawMedia
	FocusVisible = css.FocusVisible
	Before       = css.Before
	After        = css.After
	Keyframes    = css.Keyframes
	At           = css.At
	Animation    = css.Animation

	Child      = css.Child
	Descendant = css.Descendant
	Adjacent   = css.Adjacent
	Sibling    = css.Sibling
	Not        = css.Not
	Has        = css.Has
	Is         = css.Is
	NthChild   = css.NthChild
	NthOfType  = css.NthOfType
	AnB        = css.AnB
	Nth        = css.Nth
)
View Source 
var (
	El       = css.El
	SheetRef = css.SheetRef
	ClassSel = css.ClassSel
	AttrSel  = css.AttrSel
	AttrEq   = css.AttrEq
)
View Source 
var (
	Cursor             = css.Cursor
	UserSelect         = css.UserSelect
	TextTransform      = css.TextTransform
	FontVariantNumeric = css.FontVariantNumeric
)
View Source 
var (
	Shadow        = css.Shadow
	Transition    = css.Transition
	Prop          = css.Prop
	Transform     = css.Transform
	Scale         = css.Scale
	ScaleXY       = css.ScaleXY
	Rotate        = css.Rotate
	TranslateX    = css.TranslateX
	TranslateY    = css.TranslateY
	Outline       = css.Outline
	OutlineOffset = css.OutlineOffset
	Tracking      = css.Tracking
	LineHeight    = css.LineHeight
	LineHeightLen = css.LineHeightLen
	CubicBezier   = css.CubicBezier
)
View Source 
var (
	Block       = css.Display.Block
	InlineBlock = css.Display.InlineBlock
	Inline      = css.Display.Inline
	Flex        = css.Display.Flex
	InlineFlex  = css.Display.InlineFlex
	Grid        = css.Display.Grid
	Hide        = css.Display.None

	FlexRow = css.FlexDir.Row
	FlexCol = css.FlexDir.Col

	ItemsStart   = css.Items.Start
	ItemsCenter  = css.Items.Center
	ItemsEnd     = css.Items.End
	ItemsStretch = css.Items.Stretch

	JustifyStart   = css.Justify.Start
	JustifyCenter  = css.Justify.Center
	JustifyEnd     = css.Justify.End
	JustifyBetween = css.Justify.Between
	JustifyAround  = css.Justify.Around

	Relative = css.Position.Relative
	Absolute = css.Position.Absolute
	Fixed    = css.Position.Fixed
	Sticky   = css.Position.Sticky

	FontNormal   = css.FontWeight.Normal
	FontMedium   = css.FontWeight.Medium
	FontSemibold = css.FontWeight.Semibold
	FontBold     = css.FontWeight.Bold
)
View Source 
var (
	WFull = css.W(css.Full)
	HFull = css.H(css.Full)
	WAuto = css.W(css.Auto)
)

Functions

func Active 

func Active(rules ...css.Rule) []css.Rule

func Bg 

func Bg(c css.Color) css.Rule

Bg / Text set background/text color from a Layer-1 color token.

func BgC 

func BgC(c ColorToken) css.Rule

BgC / TextC / BorderC set background / text / border color from a typed theme color token: u.BgC(u.ColorSlate900). A typo is a compile error (the constant does not exist) and the token set autocompletes — the canonical, type-safe path. For a custom theme, `gwc css gen` generates the matching u.ColorToken constants.

func BgToken deprecated 

func BgToken(name string) css.Rule

BgToken / TextToken resolve a theme color token name ("slate-900"); an unknown token resolves to transparent so a typo fails visibly rather than silently inheriting.

Deprecated: prefer the typed u.BgC(u.ColorSlate900) / u.TextC(...), where a typo is a compile error instead of a runtime transparent fallback. These string forms remain for arbitrary/runtime-computed token names.

func Border 

func Border(c css.Color) css.Rule

Border sets a 1px solid border in the given color.

func BorderC 

func BorderC(c ColorToken) css.Rule

func Dark 

func Dark(rules ...css.Rule) []css.Rule

Dark is the prefers-color-scheme:dark variant.

func Fg 

func Fg(c css.Color) css.Rule

func Focus 

func Focus(rules ...css.Rule) []css.Rule

func Gap 

func Gap(index Spacing) css.Rule

Gap takes a typed spacing-scale index; GapV takes an arbitrary Layer-1 length.

func GapV 

func GapV(v css.Length) css.Rule

func GroupHover 

func GroupHover(rules ...css.Rule) []css.Rule

Group/Peer variants via parent/sibling state selectors. Mark the parent with the "group"/"peer" class (plain html.Class("group")).

func H 

func H(index Spacing) css.Rule

func Hover 

func Hover(rules ...css.Rule) []css.Rule

State variants.

func Important 

func Important(rules ...css.Rule) []css.Rule

Important appends !important to every declaration in the given rules. Use sparingly — it is the typed analog of Tailwind's "!" modifier.

func Lg 

func Lg(rules ...css.Rule) []css.Rule

func M 

func M(index Spacing) css.Rule

func Md 

func Md(rules ...css.Rule) []css.Rule

func MtN 

func MtN(index Spacing) css.Rule

MtN is a negative top margin (-mt-n): MtN(u.Spacing4) -> margin-top: -1rem.

func Mx 

func Mx(index Spacing) css.Rule

func My 

func My(index Spacing) css.Rule

func Opacity 

func Opacity(pct int) css.Rule

Opacity sets opacity from a 0..100 percentage index (Tailwind's opacity-50).

func Pad 

func Pad(index Spacing) css.Rule

func PadX 

func PadX(index Spacing) css.Rule

func PadY 

func PadY(index Spacing) css.Rule

func PeerFocus 

func PeerFocus(rules ...css.Rule) []css.Rule

func Rounded 

func Rounded(r Radius) css.Rule

Rounded resolves a typed radius key: u.Rounded(u.RadiusLg).

func Sm 

func Sm(rules ...css.Rule) []css.Rule

Responsive variants resolve their breakpoint min-width from the active theme.

func TextC 

func TextC(c ColorToken) css.Rule

func TextSize 

func TextSize(scale TextScale) css.Rule

TextSize resolves a typed type-scale key: u.TextSize(u.TextLg).

func TextToken deprecated 

func TextToken(name string) css.Rule

Deprecated: prefer the typed u.TextC(u.ColorSlate900). See BgToken.

func W 

func W(index Spacing) css.Rule

W/H take a typed spacing-scale index; WFull/HFull are 100%.

func WhenDisabled 

func WhenDisabled(rules ...css.Rule) []css.Rule

func Xl 

func Xl(rules ...css.Rule) []css.Rule

func Xl2 

func Xl2(rules ...css.Rule) []css.Rule

Types

type Angle 

type Angle = css.Angle

type Color 

type Color = css.Color
const (
	Transparent  Color = css.Transparent
	CurrentColor Color = css.CurrentCo
	Slate50      Color = css.Slate50
	Slate200     Color = css.Slate200
	Slate300     Color = css.Slate300
	Slate400     Color = css.Slate400
	Slate600     Color = css.Slate600
	Slate700     Color = css.Slate700
	Sky400       Color = css.Sky400
	Sky600       Color = css.Sky600
	Red600       Color = css.Red600
	Green500     Color = css.Green500
	Amber500     Color = css.Amber500
)

type ColorToken 

type ColorToken string

ColorToken is a typed theme color-token key, so a color reference autocompletes and a typo is a compile error instead of a silent transparent fallback. The constants below cover css.DefaultTheme; a custom theme's tokens are generated into the application package by `gwc css gen` (same shape, also u.ColorToken). 

const (
	ColorTransparent ColorToken = "transparent"
	ColorCurrent     ColorToken = "current"
	ColorWhite       ColorToken = "white"
	ColorBlack       ColorToken = "black"
	ColorSlate50     ColorToken = "slate-50"
	ColorSlate100    ColorToken = "slate-100"
	ColorSlate200    ColorToken = "slate-200"
	ColorSlate300    ColorToken = "slate-300"
	ColorSlate400    ColorToken = "slate-400"
	ColorSlate500    ColorToken = "slate-500"
	ColorSlate600    ColorToken = "slate-600"
	ColorSlate700    ColorToken = "slate-700"
	ColorSlate800    ColorToken = "slate-800"
	ColorSlate900    ColorToken = "slate-900"
	ColorSky400      ColorToken = "sky-400"
	ColorSky500      ColorToken = "sky-500"
	ColorSky600      ColorToken = "sky-600"
	ColorRed500      ColorToken = "red-500"
	ColorRed600      ColorToken = "red-600"
	ColorGreen500    ColorToken = "green-500"
	ColorAmber500    ColorToken = "amber-500"
)

type Duration 

type Duration = css.Duration

type Easing 

type Easing = css.Easing

type Frame 

type Frame = css.Frame

type Length 

type Length = css.Length
const (
	Auto Length = css.Auto
	Full Length = css.Full
	Zero Length = css.Zero
)

type MediaQ 

type MediaQ = css.MediaQuery

type NthArg 

type NthArg = css.NthArg
const (
	Odd  NthArg = css.Odd
	Even NthArg = css.Even
)

type Number 

type Number = css.Number

type Radius 

type Radius string

Radius is a typed border-radius scale key. 

const (
	RadiusNone Radius = "none"
	RadiusSm   Radius = "sm"
	RadiusMd   Radius = "md"
	RadiusLg   Radius = "lg"
	RadiusXl   Radius = "xl"
	RadiusFull Radius = "full"
)

type Rule 

type Rule = css.Rule

type Selector 

type Selector = css.Selector

type Sheet 

type Sheet = css.Sheet

type Sink 

type Sink = css.Sink

type Spacing 

type Spacing int

Spacing is a typed spacing-scale index. Built-in steps are provided as constants; any int is still valid (Tailwind's n*0.25rem formula), so arbitrary indices need no escape hatch. 

const (
	Spacing0  Spacing = 0
	Spacing1  Spacing = 1
	Spacing2  Spacing = 2
	Spacing3  Spacing = 3
	Spacing4  Spacing = 4
	Spacing5  Spacing = 5
	Spacing6  Spacing = 6
	Spacing8  Spacing = 8
	Spacing10 Spacing = 10
	Spacing12 Spacing = 12
	Spacing16 Spacing = 16
	Spacing20 Spacing = 20
	Spacing24 Spacing = 24
)

type TextScale 

type TextScale string

TextScale is a typed font-size scale key. 

const (
	TextXs   TextScale = "xs"
	TextSm   TextScale = "sm"
	TextBase TextScale = "base"
	TextLg   TextScale = "lg"
	TextXl   TextScale = "xl"
	Text2xl  TextScale = "2xl"
	Text3xl  TextScale = "3xl"
	Text4xl  TextScale = "4xl"
)

type Theme 

type Theme = css.Theme

type TransProp 

type TransProp = css.TransitionProperty

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.