Add resolved appearance engine and paired theme settings

Resolve light, dark and automatic appearance centrally and publish live theme snapshots to native surfaces and the appearance portal. Add paired preset families, custom theme imports, accessibility transforms and contrast-safe transitions.

Refine the Settings gallery and Auto controls, move overrides under advanced customization, and share palette-aware switches and circular slider thumbs. Document configuration and include theme licenses and integration coverage.

crates/ferese-theme/src/controls.rs

@@ -34,6 +34,36 @@ pub fn text_button<'a, M: Clone + 'a>(
         .class(button_style(palette, selected))
 }
 
+pub fn switch<'a, M: Clone + 'a>(enabled: bool, palette: Palette) -> button::Button<'a, M> {
+    let paint = move |focused| button::Style {
+        background: None,
+        text_color: Some(palette.text),
+        icon_color: Some(palette.text),
+        border_radius: 12.into(),
+        border_width: if focused { 1. } else { 0. },
+        border_color: palette.accent,
+        ..Default::default()
+    };
+    button::custom(crate::menus::switch(enabled, palette, 1.))
+        .padding(2)
+        .class(theme::Button::Custom {
+            active: Box::new(move |focused, _| paint(focused)),
+            hovered: Box::new(move |focused, _| paint(focused)),
+            pressed: Box::new(move |focused, _| paint(focused)),
+            disabled: Box::new(move |_| paint(false)),
+        })
+}
+
+pub(crate) fn switch_colors(palette: Palette, enabled: bool, hovered: bool) -> (Color, Color) {
+    let track = if enabled {
+        palette.accent
+    } else {
+        mix(palette.card, palette.text, if hovered { 0.18 } else { 0.12 })
+    };
+    let thumb = crate::foreground(track, palette.text);
+    (track, thumb)
+}
+
 pub fn navigation_style(p: Palette, selected: bool) -> theme::Button {
     styled_button(p, selected, true)
 }
@@ -48,7 +78,7 @@ pub fn settings_input(p: Palette) -> theme::TextInput {
         icon_color: Some(p.muted),
         text_color: Some(p.text),
         placeholder_color: p.muted,
-        selected_text_color: p.sidebar,
+        selected_text_color: p.on_accent,
         selected_fill: p.accent,
         label_color: p.muted,
     };
@@ -233,3 +263,30 @@ pub fn filled_button(fill: Color, foreground: Color, radius: f32, opacity: f32)
         disabled: Box::new(move |_| paint(0.)),
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn switch_thumb_remains_readable_in_every_preset_and_state() {
+        for preset in crate::PRESETS {
+            let resolved = ferese_config::theme::ResolvedTheme {
+                appearance: preset.appearance,
+                tokens: ferese_config::theme::preset(preset.id, preset.appearance).unwrap(),
+                ..Default::default()
+            };
+            let palette = Palette::from_resolved(&resolved);
+            for enabled in [false, true] {
+                for hovered in [false, true] {
+                    let (track, thumb) = switch_colors(palette, enabled, hovered);
+                    assert!(
+                        crate::contrast(track, thumb) >= 4.5,
+                        "{}: enabled={enabled}, hovered={hovered}",
+                        preset.name,
+                    );
+                }
+            }
+        }
+    }
+}