# Appearance and themes

> Change corner radius, accent color, fonts, borders and motion for every widget, and switch community themes live.

Umbra styles widgets through design tokens, so one setting restyles every widget that follows them. Changes apply live.

## Appearance settings

In **Settings → Appearance → Customize colors, text and size**:

| Setting | Effect |
|---|---|
| **Corner radius** | `default`, `sharp` or `round`. Overrides the theme's `--radius-s/m/l`. |
| **Accent color** | A color of your choice, or **Match Windows accent**, which follows the system accent live (lightened if it is too dark for black). Empty uses the theme's accent. |
| **Interface font and size** | Sets `--font` and `--font-scale`. Widgets that size text in `em`/`rem` follow the scale. |
| **Light text** | Brighter `--text*` colors. |
| **Window border** | On or off, and its color. |
| **Reduce transparency** | Solid `--line*` and `--accent-soft`, opaque windows. |
| **Animation speed** | `normal`, `calm` (animation durations doubled) or `off`. Windows' reduced-motion preference is respected. |
| **Size of new widgets** | The starting scale for new widgets, 0.5 to 3. |

The same settings from a terminal:

```powershell
umbractl general --corner-radius round --animation-speed calm
umbractl set-general --accent "#ff7a59" --light-text on --ui-font Consolas --font-scale 1.1 --border off --reduce-transparency on
```

## Themes

A theme restyles every widget at once: surfaces, lines, text, accent, up/down colors and corner radii. Switch in **Settings → Appearance**, or:

```powershell
umbractl themes                  # installed themes and the community catalog
umbractl install-theme ember     # install from the catalog
umbractl theme ember             # switch, live (`umbractl theme default` for Umbra Black)
umbractl remove-theme ember
```

"Umbra Black" is the built-in default. The catalog ships Ember, Glacier and Mono. Themes are **data only**: a list of named color and radius tokens with strict value checks, never code, so a theme can't load anything. Your own appearance settings (accent, corner radius, font) are applied on top of the theme.

Widgets that set `"themeable": false` in their manifest keep their own look. To make a theme, see [Build a theme](/umbra/docs/themes/build-a-theme/).

## Windows contrast themes

When Windows has a contrast theme on, Umbra maps the tokens to system colors and ignores themes and accents, so widgets stay readable. Widget authors can read about it in the [styling guide](/umbra/docs/widgets/styling/).