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Default theme surfaces are now neutral

note

This guide is accurate as of Flet 1.1.0. Later releases might add new APIs or additional migration paths.

The breaking changes and deprecations index lists the guides created for each release.

Summary​

Flet 1.1.0 changes the colors of surfaces (page background, cards, dialogs, menus, text fields, navigation bars and so on) in themes built from a seed color, including the default theme an app gets when it sets no page.theme.

  • Before: Material 3 tinted every surface with the seed hue. With the default blue seed, a "blank" light page was a lavender-tinted #f9f9ff-ish and a dark page a tinted #131318-ish.
  • Now: surfaces use a neutral grey ramp with no hue - white (#ffffff) in light mode and near-black (#121212) in dark mode. Accent colors (primary, secondary, tertiary and their containers) still come from Theme.color_scheme_seed.

The tinted look is still available with the new Theme.surfaces property set to ThemeSurfaces.TONAL.

Symptoms​

No error is raised - the change is visual. An app that sets no theme, or sets a Theme without surfaces, has a white or near-black background and grey (instead of tinted) cards, containers, outlines and text fields after the upgrade.

Migration guide​

To keep the seed-tinted Material 3 look, set surfaces to ThemeSurfaces.TONAL in both the light and the dark theme:

page.theme = ft.Theme(surfaces=ft.ThemeSurfaces.TONAL)
page.dark_theme = ft.Theme(surfaces=ft.ThemeSurfaces.TONAL)

If you set a seed color, keep it - surfaces only decides whether the seed also tints surfaces:

# Green accents on neutral surfaces (the new default)
page.theme = ft.Theme(color_scheme_seed=ft.Colors.GREEN)

# Green accents and green-tinted surfaces (the pre-1.1 look)
page.theme = ft.Theme(
    color_scheme_seed=ft.Colors.GREEN,
    surfaces=ft.ThemeSurfaces.TONAL,
)

No action needed for​

  • Apps that already set surface colors explicitly in Theme.color_scheme (for example surface or surface_container): explicit colors still win over both neutral and tonal defaults.
  • Apps that already set a white or neutral background themselves.

Timeline​

  • Changed in: 1.1.0

References​