Theme.kt

// To simplfy the example, we will use the defaults provided in the Material Theme
private val LightThemeColors = lightColors()

private val DarkThemeColors = darkColors()

@Composable
fun ProvideAppColors(
    colors: Colors,
    content: @Composable () -> Unit
) {
    val colorPalette = remember { colors }
    CompositionLocalProvider(LocalAppColors provides colorPalette, content = content)
}

private val LocalAppColors = staticCompositionLocalOf {
    LightThemeColors
}

@Composable
fun AppTheme(
    darkTheme: Boolean = isSystemInDarkTheme(),
    content: @Composable () -> Unit
) {
    val colors = if (darkTheme) DarkThemeColors else LightThemeColors

    ProvideAppColors(colors = colors) {
        MaterialTheme(
            colors = colors,
            shapes = Shapes,
            typography = typography,
            content = content
        )
    }
}

object Theme {
    val colors: Colors
        @Composable
        get() = LocalAppColors.current
}