Masks

Fading the bottom of a hero used to mean writing the same gradient twice: once for maskImage, once for -webkit-mask-image.

Now you set a stop.

css({ maskBottomFrom: '40%' })

It's solid through 40%, then it fades to transparent at the bottom. One prop. The -webkit- prefix is already there.

Fading one edge

From is where the fade starts. To is where it finishes. Skip To and it defaults to 100%.

css({ overflow: 'auto', maskBottomFrom: '80%' })
css({ maskBottomFrom: '20%', maskBottomTo: '80%' })

Prop	Fades toward
maskTopFrom	top
maskRightFrom	right
maskBottomFrom	bottom
maskLeftFrom	left

Each one has a matching To. Values are spacing tokens or raw lengths (8, 20%, 2rem).

Fading both sides

maskX and maskY are two edges, not one gradient. Left and right. Top and bottom.

css({ overflowX: 'auto', maskXFrom: '8', maskXTo: '90%' })
css({ maskYFrom: '15%', maskYTo: '85%' })

Pick maskXFrom or maskLeftFrom, not both. They write the same CSS variables. Stylesheet sort order decides the winner, not the order you wrote the props.

Stacking a fade and a spotlight

Edge fades live on the linear layer. Radial and conic are separate layers. The browser intersects them, so a bottom fade plus a radial spotlight keeps both.

css({
  maskBottomFrom: '50%',
  maskRadialFrom: '35%',
  maskRadialAt: 'center'
})

Fade the footer. Keep a soft circle of the photo.

maskBottomFrom and maskLinear both write the linear layer. Use one or the other. Stacking those two does not add a second fade. The later class overwrites the first.

Using a linear mask

maskLinear is an angle, or the same to-t / to-br map as bgGradient.

css({ maskLinear: '45', maskLinearFrom: '30%' })
css({ maskLinear: 'to-b', maskLinearFrom: '40%', maskLinearTo: '80%' })

A bare number on maskLinear is degrees: '45' means 45deg. A bare number on maskLinearFrom is spacing. That split is easy to mix up.

Using a radial mask

maskRadialAt is the center of the gradient. It is not maskPosition. maskPosition moves a maskImage.

css({
  maskRadialFrom: '20%',
  maskRadialAt: 'center',
  maskRadialShape: 'circle',
  maskRadialSize: 'farthest-side'
})

maskRadialAt accepts center, top, top left, 30% 30%, and the rest of the background-position syntax. Write the CSS — there is no topLeft alias.

Using a conic mask

css({
  maskConic: '45',
  maskConicFrom: '20%',
  maskConicTo: '80%'
})

Same degree rule as maskLinear: '45' means 45deg.

Changing stop colors

Stops default to black, then transparent. That is what you want for a normal fade. Override the color with a separate prop, not by stuffing a color into From.

css({
  maskBottomFrom: '25%',
  maskBottomFromColor: 'transparent',
  maskBottomToColor: 'black'
})

Every From / To has a matching FromColor / ToColor: maskBottomFromColor, maskLinearToColor, maskRadialFromColor, maskConicToColor. Color tokens and opacity modifiers work (red.500, black/50).

Using a raw mask image

A PNG, an SVG, or a gradient you already have goes on maskImage. That is the escape hatch. It replaces the fade layers. Do not mix it with maskBottomFrom.

css({
  maskImage: 'url(/scribble.png)',
  maskSize: 'cover',
  maskPosition: 'center',
  maskRepeat: 'no-repeat'
})

Using CSS mask properties

These map 1:1 to CSS. Each one also emits the -webkit- prefix.

Prop	CSS property	Values
mask	mask	shorthand
maskImage	mask-image	none, url(...), any image
maskSize	mask-size	auto, cover, contain, any length
maskPosition	mask-position	center, top left, 50% 50%, …
maskRepeat	mask-repeat	repeat, no-repeat, repeat-x, repeat-y, …
maskClip	mask-clip	border-box, padding-box, content-box, …
maskOrigin	mask-origin	border-box, padding-box, content-box, …
maskComposite	mask-composite	add, subtract, intersect, exclude
maskMode	mask-mode	alpha, luminance, match-source
maskType	mask-type	alpha, luminance (SVG <mask> only)

Fade helpers composite as intersect. Set maskComposite to change that — it wins wherever you put it, because the helpers read the same variable.

css({
  maskBottomFrom: '50%',
  maskRadialFrom: '70%',
  maskComposite: 'add'
})

Under strict tokens

Stops resolve against spacing, so a raw length needs the escape hatch.

css({ maskBottomFrom: '4' }) // spacing token
css({ maskBottomFrom: '[20%]' }) // raw percentage

Colors work the same way: maskBottomFromColor: 'red.500', or '[rebeccapurple]'.

What does not compose

• maskImage and the fade helpers. Both write mask-image, so stylesheet sort order picks the winner, not the order you wrote the props. Pick one.
• maskBottomFrom and maskLinear. Same layer. One overwrites the other.
• maskXFrom and maskLeftFrom. Same variables. Pick one.
• Logical edges. There is no maskStartFrom or maskEndFrom. Fade direction is visual: top, right, bottom, left.

Start with maskBottomFrom. Add a second helper only when one edge is not enough.

How it works

The helpers write CSS variables — --mask-linear, --mask-bottom-from-position, and friends — which Panda registers with @property. Two things follow from that.

Registrations are inherits: false, so a fade on a parent cannot leak into a child. And Panda only emits the registrations your stylesheet actually references, so a project that never masks pays nothing for them.

You can set the variables yourself when a helper doesn't cover the case.

css({ maskBottomFrom: '50%', '--mask-bottom-from-color': 'rebeccapurple' })