struct Theme

Creates a theme. Every parameter matches the property of the same name.

Emphasis for headings and focus rings.

Window background, behind everything.

Colour of outlines and dividers.

Width of outlines and dividers, in points.

Palettes the system theme understands, in the order Settings lists them.

The diagram canvas.

Width of the text caret, in points.

Inner padding for controls such as text fields.

Default corner radius for panels and controls. 0 gives hard corners.

App-wide default theme. Environment.current.theme falls through to this wherever no .theme(_:) override is in scope, so setting it still reaches everything that never opted out — but a subtree wearing .theme(_:) no longer has to go through here at all.

The palette this app shipped with, kept as-is so the theme migration changes nothing visually until someone chooses a different one.

Warm charcoal with copper light, the night-side counterpart to paper.

Dark's greys are cool on purpose — they sit behind code and disappear. Ember is the same darkness with the colour temperature flipped, so a desktop that wants firelight rather than a monitor in a basement has somewhere to go that is still a dark theme.

Focus ring colour. nil uses accent.

Shape of the focused-field chrome. Defaults to a full rounded outline.

Stroke thickness for the focus ring (also used by .underline).

Near-black with a hard white, for a desktop that wants contrast rather than atmosphere. The accent keeps a drop of blue so links and focus rings do not disappear into the grey.

Row highlight under the pointer.

Inset surfaces: text fields, wells.

A light palette: dark text on pale surfaces.

One cool slate hue for every grey and every quiet text, so nothing reads as a second palette. The muted and dim text used to be the dark theme's green-grey, olive on these surfaces; the background was tinted cyan beside a neutral panel; and the hover was a saturated sky blue, a loud block under the pointer where dark's is a quiet step up.

Deep forest. Green enough to be a choice, quiet enough to put a wall of icons on — the same job nebula does in indigo.

Deep indigo with a cyan/magenta pair, for surfaces that sit over a desktop rather than filling a window.

The greys exist to disappear behind content, which is right for an editor and wrong for a launcher: there the surface is most of what is on screen, and neutral grey over a photograph reads as a smudge rather than as a thing. This is still dark and still low-chroma enough to put a wall of app icons on, but it has a hue, so what is behind it is clearly behind something.

selected and accent are far apart on the wheel on purpose — the two mean different things (where you are, versus what is important) and a palette that makes them cousins loses that distinction exactly when a keyboard-driven grid needs it most.

Called after a compositor system-theme push is applied to current. Apps that paint their own paper (a terminal, a player) can retint here. Nil is the usual case — Theme.current already rebuilt the tree.

Side panels and other raised chrome.

Warm paper. light is a cool daylight grey; this is the same brightness with the yellow left in, so a page reads as a page rather than as a window.

Current selection in a list — deliberately distinct from accent.

Text selection highlight.

Default distance between adjacent views in a stack when its spacing is nil.

The faintest text: disabled menu items, shortcut hints, quotes.

Placeholders and hints.

Body text.

Labels, captions and other text one step down from the body.

The names the compositor's system theme understands.