diff --git a/Cargo.lock b/Cargo.lock
index 6ebdef0..5316ae2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1681,6 +1681,7 @@ dependencies = [
 name = "ferese-config"
 version = "0.1.0"
 dependencies = [
+ "ferese-theme-model",
  "jiff",
  "kdl",
  "serde",
@@ -1811,6 +1812,13 @@ dependencies = [
  "wayland-client",
 ]
 
+[[package]]
+name = "ferese-theme-model"
+version = "0.1.0"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "feresectl"
 version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
index 8dd2f74..ba17ad2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,6 +6,7 @@ members = [
     "crates/ferese-core",
     "crates/ferese-config",
     "crates/ferese-theme",
+    "crates/ferese-theme-model",
     "crates/ferese-ipc",
     "crates/ferese-layout",
     "crates/ferese-protocols",
diff --git a/crates/ferese-config/Cargo.toml b/crates/ferese-config/Cargo.toml
index 1490f75..584e6fd 100644
--- a/crates/ferese-config/Cargo.toml
+++ b/crates/ferese-config/Cargo.toml
@@ -6,6 +6,7 @@ license.workspace = true
 rust-version.workspace = true
 
 [dependencies]
+ferese-theme-model = { path = "../ferese-theme-model" }
 jiff.workspace = true
 kdl = "6.7.1"
 serde.workspace = true
diff --git a/crates/ferese-config/src/families.rs b/crates/ferese-config/src/families.rs
index 0ef5058..020d402 100644
--- a/crates/ferese-config/src/families.rs
+++ b/crates/ferese-config/src/families.rs
@@ -1,54 +1,5 @@
-use serde::{Deserialize, Serialize};
-
-use crate::theme::{Appearance, Tokens};
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Palette {
-    pub background: String,
-    pub bar: String,
-    pub surface: String,
-    pub text: String,
-    pub muted: String,
-    pub accent: String,
-}
-
-impl From<&Tokens> for Palette {
-    fn from(tokens: &Tokens) -> Self {
-        Self {
-            background: tokens.colors.surface_base.clone(),
-            bar: tokens.surface.bar.background.clone(),
-            surface: tokens.colors.surface_raised.clone(),
-            text: tokens.colors.text_primary.clone(),
-            muted: tokens.colors.text_muted.clone(),
-            accent: tokens.colors.accent.clone(),
-        }
-    }
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Family {
-    pub id: String,
-    pub name: String,
-    pub light: Option<Palette>,
-    pub dark: Option<Palette>,
-}
-
-impl Family {
-    pub fn palette(&self, appearance: Appearance) -> Option<&Palette> {
-        match appearance {
-            Appearance::Light => self.light.as_ref(),
-            Appearance::Dark => self.dark.as_ref(),
-        }
-    }
-
-    pub fn availability(&self) -> &'static str {
-        match (self.light.is_some(), self.dark.is_some()) {
-            (true, true) => "light and dark",
-            (true, false) => "light only",
-            _ => "dark only",
-        }
-    }
-}
+use crate::theme::Appearance;
+pub use ferese_theme_model::families::{Family, Palette};
 
 pub const BUILTINS: [(&str, &str, &str, &str); 6] = [
     ("ferese-blue", "Ferese Blue", "ferese-blue-light", "ferese-blue"),
diff --git a/crates/ferese-config/src/theme.rs b/crates/ferese-config/src/theme.rs
index 6166f5f..ba3e9ea 100644
--- a/crates/ferese-config/src/theme.rs
+++ b/crates/ferese-config/src/theme.rs
@@ -8,34 +8,11 @@ use serde::{Deserialize, Serialize};
 use serde_json::{Value, json};
 
 use crate::Document;
+pub use ferese_theme_model::*;
 
 pub const SCHEMA_VERSION: u32 = 2;
 pub const TRANSITION_MS: u64 = 250;
 
-#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
-#[serde(rename_all = "lowercase")]
-pub enum Appearance {
-    Light,
-    #[default]
-    Dark,
-}
-
-#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
-#[serde(rename_all = "lowercase")]
-pub enum Mode {
-    Light,
-    #[default]
-    Dark,
-    Auto,
-}
-
-#[derive(Clone, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
-#[serde(default)]
-pub struct Accessibility {
-    pub increase_contrast: bool,
-    pub reduce_transparency: bool,
-}
-
 #[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
 #[serde(default)]
 pub struct Selection {
@@ -225,105 +202,8 @@ impl Default for Policy {
     }
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Colors {
-    pub surface_base: String,
-    pub surface_raised: String,
-    pub application_background: String,
-    pub text_primary: String,
-    pub text_muted: String,
-    pub accent: String,
-    pub on_accent: String,
-    pub border: String,
-    pub shadow: String,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Material {
-    pub style: String,
-    pub opacity: f64,
-    pub blur_radius: f64,
-    pub tint_strength: f64,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Geometry {
-    pub border_width: f64,
-    pub focus_ring_width: f64,
-    pub window_radius: f64,
-    pub shell_radius: f64,
-    pub top_bar_height: f64,
-    pub top_bar_margin_top: i32,
-    pub top_bar_margin_horizontal: i32,
-    pub top_bar_window_gap: i32,
-    pub panel_padding: f64,
-    pub control_gap: f64,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Typography {
-    pub font_family: String,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Background {
-    pub path: Option<PathBuf>,
-    pub lock_path: Option<PathBuf>,
-    pub mode: String,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct BarSurface {
-    pub background: String,
-    pub text_primary: String,
-    pub text_muted: String,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Surfaces {
-    pub bar: BarSurface,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct SoftShadow {
-    pub offset_y: f64,
-    pub blur: f64,
-    pub opacity: f64,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Shadows {
-    pub soft: SoftShadow,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Gradient {
-    pub from: String,
-    pub to: String,
-    pub angle: f64,
-}
-
-#[derive(Clone, Debug, Default, Deserialize, Serialize, PartialEq)]
-pub struct Paint {
-    pub gradient: Option<Gradient>,
-}
-
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct Tokens {
-    pub colors: Colors,
-    pub material: Material,
-    pub geometry: Geometry,
-    pub typography: Typography,
-    pub background: Background,
-    pub surface: Surfaces,
-    pub shadow: Shadows,
-    pub border: Paint,
-    pub focus_ring: Paint,
-}
-
-impl Default for Tokens {
-    fn default() -> Self {
-        serde_json::from_value(json!({
+pub fn default_tokens() -> Tokens {
+    serde_json::from_value(json!({
             "colors": {"surface_base":"#111821", "surface_raised":"#1E2530", "application_background":"#171E27", "text_primary":"#F4F7FB", "text_muted":"#8793A2",
                 "accent":"#3D7BE6", "on_accent":"#FFFFFF", "border":"#FFFFFF18", "shadow":"#00000055"},
             "material":{"style":"solid","opacity":0.78,"blur_radius":12.0,"tint_strength":0.5},
@@ -337,27 +217,15 @@ impl Default for Tokens {
             "border":{"gradient":null},"focus_ring":{"gradient":null}
         }))
         .expect("valid built-in theme")
-    }
 }
 
-#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
-pub struct ResolvedTheme {
-    pub appearance: Appearance,
-    pub tokens: Tokens,
-    pub requested_accent: String,
-    pub accessibility: Accessibility,
-    pub reduced_motion: bool,
-}
-
-impl Default for ResolvedTheme {
-    fn default() -> Self {
-        Self {
-            appearance: Appearance::Dark,
-            requested_accent: "#3D7BE6".into(),
-            tokens: Tokens::default(),
-            accessibility: Accessibility::default(),
-            reduced_motion: false,
-        }
+pub fn default_theme() -> ResolvedTheme {
+    ResolvedTheme {
+        appearance: Appearance::Dark,
+        requested_accent: "#3D7BE6".into(),
+        tokens: default_tokens(),
+        accessibility: Accessibility::default(),
+        reduced_motion: false,
     }
 }
 
@@ -382,8 +250,8 @@ impl Default for Snapshot {
             version: SCHEMA_VERSION,
             revision: 0,
             mode: Mode::Dark,
-            theme: ResolvedTheme::default(),
-            presented: ResolvedTheme::default(),
+            theme: default_theme(),
+            presented: default_theme(),
             warnings: vec![],
             error: None,
             families: crate::families::builtins(),
@@ -711,7 +579,7 @@ pub fn preset(name: &str, appearance: Appearance) -> Result<Tokens, String> {
         if preset.appearance != appearance {
             return Err(format!("Preset {name} does not support {appearance:?}"));
         }
-        let mut tokens = Tokens::default();
+        let mut tokens = default_tokens();
         tokens.colors.surface_base = preset.base.into();
         tokens.colors.surface_raised = preset.raised.into();
         tokens.colors.application_background = preset.application_background.into();
@@ -737,7 +605,7 @@ pub fn preset(name: &str, appearance: Appearance) -> Result<Tokens, String> {
         tokens.shadow.soft.opacity = preset.shadow_opacity;
         return Ok(tokens);
     }
-    let mut t = Tokens::default();
+    let mut t = default_tokens();
     let (base, text, muted, accent, border) = match name {
         "monochrome" => ("#101012", "#EDEDF0", "#97979F", "#E5E5E5", "#FFFFFF18"),
         "dracula" => ("#282A36", "#F8F8F2", "#A4ADCD", "#BD93F9", "#44475A"),
@@ -863,103 +731,6 @@ fn validate(tokens: &Tokens) -> Result<(), String> {
     Ok(())
 }
 
-pub fn rgba(s: &str) -> Result<[f64; 4], String> {
-    let hex = s.strip_prefix('#').ok_or_else(|| format!("Invalid color: {s}"))?;
-    if !hex.is_ascii() || !matches!(hex.len(), 6 | 8) {
-        return Err(format!("Invalid color: {s}"));
-    }
-    let mut out = [1.; 4];
-    for (i, c) in out.iter_mut().enumerate().take(hex.len() / 2) {
-        *c = f64::from(u8::from_str_radix(&hex[i * 2..i * 2 + 2], 16).map_err(|_| format!("Invalid color: {s}"))?)
-            / 255.;
-    }
-    Ok(out)
-}
-
-pub fn hex(c: [f64; 4]) -> String {
-    format!(
-        "#{:02X}{:02X}{:02X}{:02X}",
-        (c[0].clamp(0., 1.) * 255.).round() as u8,
-        (c[1].clamp(0., 1.) * 255.).round() as u8,
-        (c[2].clamp(0., 1.) * 255.).round() as u8,
-        (c[3].clamp(0., 1.) * 255.).round() as u8
-    )
-}
-
-pub fn luminance(c: [f64; 4]) -> f64 {
-    let linear = |v: f64| {
-        if v <= 0.04045 {
-            v / 12.92
-        } else {
-            ((v + 0.055) / 1.055).powf(2.4)
-        }
-    };
-    0.2126 * linear(c[0]) + 0.7152 * linear(c[1]) + 0.0722 * linear(c[2])
-}
-
-pub fn contrast(a: [f64; 4], b: [f64; 4]) -> f64 {
-    let (a, b) = (luminance(a), luminance(b));
-    (a.max(b) + 0.05) / (a.min(b) + 0.05)
-}
-
-pub fn composite(fg: [f64; 4], bg: [f64; 4]) -> [f64; 4] {
-    let mut c = [0.; 4];
-    for i in 0..3 {
-        c[i] = fg[i] * fg[3] + bg[i] * (1. - fg[3]);
-    }
-    c[3] = 1.;
-    c
-}
-
-fn blend(a: [f64; 4], b: [f64; 4], p: f64) -> [f64; 4] {
-    std::array::from_fn(|i| a[i] + (b[i] - a[i]) * p)
-}
-
-pub fn readable(preferred: [f64; 4], background: [f64; 4], minimum: f64) -> [f64; 4] {
-    let mut preferred = preferred;
-    preferred[3] = 1.;
-    if contrast(preferred, background) >= minimum {
-        return preferred;
-    }
-    let black = [0., 0., 0., 1.];
-    let white = [1., 1., 1., 1.];
-    let target = if contrast(black, background) > contrast(white, background) {
-        black
-    } else {
-        white
-    };
-    for step in 1..=100 {
-        let c = blend(preferred, target, f64::from(step) / 100.);
-        if contrast(rgba(&hex(c)).expect("generated color"), background) >= minimum {
-            return c;
-        }
-    }
-    target
-}
-
-fn readable_across(mut preferred: [f64; 4], backgrounds: &[[f64; 4]], minimum: f64) -> [f64; 4] {
-    preferred[3] = 1.;
-    let score = |color| {
-        backgrounds
-            .iter()
-            .map(|background| contrast(color, *background))
-            .fold(f64::INFINITY, f64::min)
-    };
-    if score(preferred) >= minimum {
-        return preferred;
-    }
-    let black = [0., 0., 0., 1.];
-    let white = [1.; 4];
-    let target = if score(black) > score(white) { black } else { white };
-    for step in 1..=100 {
-        let color = rgba(&hex(blend(preferred, target, f64::from(step) / 100.))).unwrap();
-        if score(color) >= minimum {
-            return color;
-        }
-    }
-    target
-}
-
 fn transform(t: &mut Tokens, accessibility: &Accessibility, warnings: &mut Vec<String>) {
     let surface = rgba(&t.colors.surface_base).expect("validated surface");
     let mut requested = rgba(&t.colors.accent).expect("validated accent");
@@ -1075,180 +846,6 @@ fn resolve_material_contrast(tokens: &mut Tokens, minimum: f64) {
     }
 }
 
-fn material_bounds(mut surface: [f64; 4], opacity: f64) -> [[f64; 4]; 2] {
-    surface[3] = opacity;
-    [composite(surface, [0., 0., 0., 1.]), composite(surface, [1.; 4])]
-}
-
-fn material_foreground(preferred: [f64; 4], backgrounds: [[f64; 4]; 2]) -> [f64; 4] {
-    let black = [0., 0., 0., 1.];
-    let white = [1.; 4];
-    let (target, worst) = if contrast(black, backgrounds[0]) >= contrast(white, backgrounds[1]) {
-        (black, backgrounds[0])
-    } else {
-        (white, backgrounds[1])
-    };
-    let result = readable(preferred, worst, 4.5);
-    let outside = luminance(result) < luminance(backgrounds[0]) || luminance(result) > luminance(backgrounds[1]);
-    if outside
-        && backgrounds
-            .iter()
-            .all(|background| contrast(rgba(&hex(result)).unwrap(), *background) >= 4.5)
-    {
-        result
-    } else {
-        target
-    }
-}
-
-impl ResolvedTheme {
-    /// Bound contrast across all backdrops instead of interpolating foregrounds.
-    pub fn transition(&self, to: &Self, progress: f64) -> Self {
-        if to.reduced_motion || self.accessibility != to.accessibility || progress >= 1.0 {
-            return to.clone();
-        }
-        if progress <= 0.0 || self == to {
-            return self.clone();
-        }
-        let p = progress.clamp(0., 1.);
-        let p = p * p * (3. - 2. * p);
-        let mut frame = to.clone();
-        let mix = |a: &str, b: &str| hex(blend(rgba(a).unwrap(), rgba(b).unwrap(), p));
-        frame.tokens.colors.surface_base = mix(&self.tokens.colors.surface_base, &to.tokens.colors.surface_base);
-        frame.tokens.colors.surface_raised = mix(&self.tokens.colors.surface_raised, &to.tokens.colors.surface_raised);
-        frame.tokens.colors.application_background = mix(
-            &self.tokens.colors.application_background,
-            &to.tokens.colors.application_background,
-        );
-        frame.tokens.colors.accent = mix(&self.tokens.colors.accent, &to.tokens.colors.accent);
-        frame.tokens.colors.border = mix(&self.tokens.colors.border, &to.tokens.colors.border);
-        frame.tokens.colors.shadow = mix(&self.tokens.colors.shadow, &to.tokens.colors.shadow);
-        frame.tokens.surface.bar.background =
-            mix(&self.tokens.surface.bar.background, &to.tokens.surface.bar.background);
-        frame.tokens.material.opacity =
-            self.tokens.material.opacity + (to.tokens.material.opacity - self.tokens.material.opacity) * p;
-        frame.tokens.material.tint_strength = self.tokens.material.tint_strength
-            + (to.tokens.material.tint_strength - self.tokens.material.tint_strength) * p;
-        frame.tokens.shadow.soft.opacity =
-            self.tokens.shadow.soft.opacity + (to.tokens.shadow.soft.opacity - self.tokens.shadow.soft.opacity) * p;
-        let preferred = if p < 0.5 { self } else { to };
-        frame.appearance = preferred.appearance;
-        if self.appearance == to.appearance {
-            let body = [
-                rgba(&frame.tokens.colors.surface_base).unwrap(),
-                rgba(&frame.tokens.colors.surface_raised).unwrap(),
-                rgba(&frame.tokens.colors.application_background).unwrap(),
-            ];
-            let minimum = if to.accessibility.increase_contrast { 7.0 } else { 4.5 };
-            frame.tokens.colors.text_primary = hex(readable_across(
-                rgba(&preferred.tokens.colors.text_primary).unwrap(),
-                &body,
-                minimum,
-            ));
-            frame.tokens.colors.text_muted = hex(readable_across(
-                rgba(&preferred.tokens.colors.text_muted).unwrap(),
-                &body,
-                minimum,
-            ));
-            let bar = rgba(&frame.tokens.surface.bar.background).unwrap();
-            frame.tokens.surface.bar.text_primary = hex(readable(
-                rgba(&preferred.tokens.surface.bar.text_primary).unwrap(),
-                bar,
-                minimum,
-            ));
-            frame.tokens.surface.bar.text_muted = hex(readable(
-                rgba(&preferred.tokens.surface.bar.text_muted).unwrap(),
-                bar,
-                minimum,
-            ));
-            frame.tokens.colors.on_accent = hex(readable(
-                rgba(&preferred.tokens.colors.on_accent).unwrap(),
-                rgba(&frame.tokens.colors.accent).unwrap(),
-                4.5,
-            ));
-            return frame;
-        }
-        let base = rgba(&frame.tokens.colors.surface_base).unwrap();
-        let raised = rgba(&frame.tokens.colors.surface_raised).unwrap();
-        let app = rgba(&frame.tokens.colors.application_background).unwrap();
-        let minimum = [base, raised, app]
-            .into_iter()
-            .map(luminance)
-            .fold(f64::INFINITY, f64::min);
-        let maximum = [base, raised, app].into_iter().map(luminance).fold(0., f64::max);
-        if ((minimum + 0.05) / 0.05).max(1.05 / (maximum + 0.05)) < 4.5 {
-            frame.tokens.colors.surface_raised = frame.tokens.colors.surface_base.clone();
-            frame.tokens.colors.application_background = frame.tokens.colors.surface_base.clone();
-        }
-        let surface = rgba(&frame.tokens.colors.surface_base).unwrap();
-        let bar = rgba(&frame.tokens.surface.bar.background).unwrap();
-        let mut opacity = if frame.tokens.material.style == "solid" {
-            1.
-        } else {
-            frame.tokens.material.opacity * frame.tokens.material.tint_strength
-        };
-        for step in 0..=100 {
-            let candidate = opacity + (1. - opacity) * f64::from(step) / 100.;
-            let backgrounds = material_bounds(surface, candidate);
-            let raised = rgba(&frame.tokens.colors.surface_raised).unwrap();
-            let app = rgba(&frame.tokens.colors.application_background).unwrap();
-            let all = [backgrounds[0], backgrounds[1], raised, app];
-            let minimum = all.into_iter().map(luminance).fold(f64::INFINITY, f64::min);
-            let maximum = all.into_iter().map(luminance).fold(0., f64::max);
-            let bar = material_bounds(bar, candidate);
-            let readable = ((minimum + 0.05) / 0.05).max(1.05 / (maximum + 0.05)) >= 4.5
-                && contrast([0., 0., 0., 1.], bar[0]).max(contrast([1.; 4], bar[1])) >= 4.5;
-            if readable {
-                opacity = candidate;
-                break;
-            }
-        }
-        if opacity > frame.tokens.material.opacity {
-            frame.tokens.material.opacity = opacity;
-            frame.tokens.material.tint_strength = 1.;
-        } else if frame.tokens.material.opacity > 0. {
-            frame.tokens.material.tint_strength = opacity / frame.tokens.material.opacity;
-        }
-        let surface = material_bounds(surface, opacity);
-        let bar = material_bounds(bar, opacity);
-        let raised = rgba(&frame.tokens.colors.surface_raised).unwrap();
-        let app = rgba(&frame.tokens.colors.application_background).unwrap();
-        let body_backgrounds = [surface[0], surface[1], raised, app];
-        let body_bounds = [
-            *body_backgrounds
-                .iter()
-                .min_by(|a, b| luminance(**a).total_cmp(&luminance(**b)))
-                .unwrap(),
-            *body_backgrounds
-                .iter()
-                .max_by(|a, b| luminance(**a).total_cmp(&luminance(**b)))
-                .unwrap(),
-        ];
-        frame.tokens.colors.text_primary = hex(material_foreground(
-            rgba(&preferred.tokens.colors.text_primary).unwrap(),
-            body_bounds,
-        ));
-        frame.tokens.colors.text_muted = hex(material_foreground(
-            rgba(&preferred.tokens.colors.text_muted).unwrap(),
-            body_bounds,
-        ));
-        frame.tokens.surface.bar.text_primary = hex(material_foreground(
-            rgba(&preferred.tokens.surface.bar.text_primary).unwrap(),
-            bar,
-        ));
-        frame.tokens.surface.bar.text_muted = hex(material_foreground(
-            rgba(&preferred.tokens.surface.bar.text_muted).unwrap(),
-            bar,
-        ));
-        frame.tokens.colors.on_accent = hex(readable(
-            rgba(&preferred.tokens.colors.on_accent).unwrap(),
-            rgba(&frame.tokens.colors.accent).unwrap(),
-            4.5,
-        ));
-        frame
-    }
-}
-
 pub type ImportedFamily = (crate::families::Family, (Option<Tokens>, Option<Tokens>), Vec<String>);
 
 pub fn import_family(id: &str, source: &str) -> Result<ImportedFamily, String> {
@@ -1758,6 +1355,6 @@ mod tests {
             .theme;
         assert_eq!(light.appearance, Appearance::Light);
         light.reduced_motion = true;
-        assert_eq!(ResolvedTheme::default().transition(&light, 0.), light);
+        assert_eq!(default_theme().transition(&light, 0.), light);
     }
 }
diff --git a/crates/ferese-theme-model/Cargo.toml b/crates/ferese-theme-model/Cargo.toml
new file mode 100644
index 0000000..748b4eb
--- /dev/null
+++ b/crates/ferese-theme-model/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "ferese-theme-model"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+serde.workspace = true
diff --git a/crates/ferese-theme-model/src/color.rs b/crates/ferese-theme-model/src/color.rs
new file mode 100644
index 0000000..9cacd2d
--- /dev/null
+++ b/crates/ferese-theme-model/src/color.rs
@@ -0,0 +1,272 @@
+use crate::ResolvedTheme;
+
+pub fn rgba(s: &str) -> Result<[f64; 4], String> {
+    let hex = s.strip_prefix('#').ok_or_else(|| format!("Invalid color: {s}"))?;
+    if !hex.is_ascii() || !matches!(hex.len(), 6 | 8) {
+        return Err(format!("Invalid color: {s}"));
+    }
+    let mut out = [1.; 4];
+    for (i, c) in out.iter_mut().enumerate().take(hex.len() / 2) {
+        *c = f64::from(u8::from_str_radix(&hex[i * 2..i * 2 + 2], 16).map_err(|_| format!("Invalid color: {s}"))?)
+            / 255.;
+    }
+    Ok(out)
+}
+
+pub fn hex(c: [f64; 4]) -> String {
+    format!(
+        "#{:02X}{:02X}{:02X}{:02X}",
+        (c[0].clamp(0., 1.) * 255.).round() as u8,
+        (c[1].clamp(0., 1.) * 255.).round() as u8,
+        (c[2].clamp(0., 1.) * 255.).round() as u8,
+        (c[3].clamp(0., 1.) * 255.).round() as u8
+    )
+}
+
+pub fn luminance(c: [f64; 4]) -> f64 {
+    let linear = |v: f64| {
+        if v <= 0.04045 {
+            v / 12.92
+        } else {
+            ((v + 0.055) / 1.055).powf(2.4)
+        }
+    };
+    0.2126 * linear(c[0]) + 0.7152 * linear(c[1]) + 0.0722 * linear(c[2])
+}
+
+pub fn contrast(a: [f64; 4], b: [f64; 4]) -> f64 {
+    let (a, b) = (luminance(a), luminance(b));
+    (a.max(b) + 0.05) / (a.min(b) + 0.05)
+}
+
+pub fn composite(fg: [f64; 4], bg: [f64; 4]) -> [f64; 4] {
+    let mut c = [0.; 4];
+    for i in 0..3 {
+        c[i] = fg[i] * fg[3] + bg[i] * (1. - fg[3]);
+    }
+    c[3] = 1.;
+    c
+}
+
+pub fn blend(a: [f64; 4], b: [f64; 4], p: f64) -> [f64; 4] {
+    std::array::from_fn(|i| a[i] + (b[i] - a[i]) * p)
+}
+
+pub fn readable(preferred: [f64; 4], background: [f64; 4], minimum: f64) -> [f64; 4] {
+    let mut preferred = preferred;
+    preferred[3] = 1.;
+    if contrast(preferred, background) >= minimum {
+        return preferred;
+    }
+    let black = [0., 0., 0., 1.];
+    let white = [1., 1., 1., 1.];
+    let target = if contrast(black, background) > contrast(white, background) {
+        black
+    } else {
+        white
+    };
+    for step in 1..=100 {
+        let c = blend(preferred, target, f64::from(step) / 100.);
+        if contrast(rgba(&hex(c)).expect("generated color"), background) >= minimum {
+            return c;
+        }
+    }
+    target
+}
+
+pub fn readable_across(mut preferred: [f64; 4], backgrounds: &[[f64; 4]], minimum: f64) -> [f64; 4] {
+    preferred[3] = 1.;
+    let score = |color| {
+        backgrounds
+            .iter()
+            .map(|background| contrast(color, *background))
+            .fold(f64::INFINITY, f64::min)
+    };
+    if score(preferred) >= minimum {
+        return preferred;
+    }
+    let black = [0., 0., 0., 1.];
+    let white = [1.; 4];
+    let target = if score(black) > score(white) { black } else { white };
+    for step in 1..=100 {
+        let color = rgba(&hex(blend(preferred, target, f64::from(step) / 100.))).unwrap();
+        if score(color) >= minimum {
+            return color;
+        }
+    }
+    target
+}
+
+pub fn material_bounds(mut surface: [f64; 4], opacity: f64) -> [[f64; 4]; 2] {
+    surface[3] = opacity;
+    [composite(surface, [0., 0., 0., 1.]), composite(surface, [1.; 4])]
+}
+
+fn material_foreground(preferred: [f64; 4], backgrounds: [[f64; 4]; 2]) -> [f64; 4] {
+    let black = [0., 0., 0., 1.];
+    let white = [1.; 4];
+    let (target, worst) = if contrast(black, backgrounds[0]) >= contrast(white, backgrounds[1]) {
+        (black, backgrounds[0])
+    } else {
+        (white, backgrounds[1])
+    };
+    let result = readable(preferred, worst, 4.5);
+    let outside = luminance(result) < luminance(backgrounds[0]) || luminance(result) > luminance(backgrounds[1]);
+    if outside
+        && backgrounds
+            .iter()
+            .all(|background| contrast(rgba(&hex(result)).unwrap(), *background) >= 4.5)
+    {
+        result
+    } else {
+        target
+    }
+}
+
+impl ResolvedTheme {
+    /// Bound contrast across all backdrops instead of interpolating foregrounds.
+    pub fn transition(&self, to: &Self, progress: f64) -> Self {
+        if to.reduced_motion || self.accessibility != to.accessibility || progress >= 1.0 {
+            return to.clone();
+        }
+        if progress <= 0.0 || self == to {
+            return self.clone();
+        }
+        let p = progress.clamp(0., 1.);
+        let p = p * p * (3. - 2. * p);
+        let mut frame = to.clone();
+        let mix = |a: &str, b: &str| hex(blend(rgba(a).unwrap(), rgba(b).unwrap(), p));
+        frame.tokens.colors.surface_base = mix(&self.tokens.colors.surface_base, &to.tokens.colors.surface_base);
+        frame.tokens.colors.surface_raised = mix(&self.tokens.colors.surface_raised, &to.tokens.colors.surface_raised);
+        frame.tokens.colors.application_background = mix(
+            &self.tokens.colors.application_background,
+            &to.tokens.colors.application_background,
+        );
+        frame.tokens.colors.accent = mix(&self.tokens.colors.accent, &to.tokens.colors.accent);
+        frame.tokens.colors.border = mix(&self.tokens.colors.border, &to.tokens.colors.border);
+        frame.tokens.colors.shadow = mix(&self.tokens.colors.shadow, &to.tokens.colors.shadow);
+        frame.tokens.surface.bar.background =
+            mix(&self.tokens.surface.bar.background, &to.tokens.surface.bar.background);
+        frame.tokens.material.opacity =
+            self.tokens.material.opacity + (to.tokens.material.opacity - self.tokens.material.opacity) * p;
+        frame.tokens.material.tint_strength = self.tokens.material.tint_strength
+            + (to.tokens.material.tint_strength - self.tokens.material.tint_strength) * p;
+        frame.tokens.shadow.soft.opacity =
+            self.tokens.shadow.soft.opacity + (to.tokens.shadow.soft.opacity - self.tokens.shadow.soft.opacity) * p;
+        let preferred = if p < 0.5 { self } else { to };
+        frame.appearance = preferred.appearance;
+        if self.appearance == to.appearance {
+            let body = [
+                rgba(&frame.tokens.colors.surface_base).unwrap(),
+                rgba(&frame.tokens.colors.surface_raised).unwrap(),
+                rgba(&frame.tokens.colors.application_background).unwrap(),
+            ];
+            let minimum = if to.accessibility.increase_contrast { 7.0 } else { 4.5 };
+            frame.tokens.colors.text_primary = hex(readable_across(
+                rgba(&preferred.tokens.colors.text_primary).unwrap(),
+                &body,
+                minimum,
+            ));
+            frame.tokens.colors.text_muted = hex(readable_across(
+                rgba(&preferred.tokens.colors.text_muted).unwrap(),
+                &body,
+                minimum,
+            ));
+            let bar = rgba(&frame.tokens.surface.bar.background).unwrap();
+            frame.tokens.surface.bar.text_primary = hex(readable(
+                rgba(&preferred.tokens.surface.bar.text_primary).unwrap(),
+                bar,
+                minimum,
+            ));
+            frame.tokens.surface.bar.text_muted = hex(readable(
+                rgba(&preferred.tokens.surface.bar.text_muted).unwrap(),
+                bar,
+                minimum,
+            ));
+            frame.tokens.colors.on_accent = hex(readable(
+                rgba(&preferred.tokens.colors.on_accent).unwrap(),
+                rgba(&frame.tokens.colors.accent).unwrap(),
+                4.5,
+            ));
+            return frame;
+        }
+        let base = rgba(&frame.tokens.colors.surface_base).unwrap();
+        let raised = rgba(&frame.tokens.colors.surface_raised).unwrap();
+        let app = rgba(&frame.tokens.colors.application_background).unwrap();
+        let minimum = [base, raised, app]
+            .into_iter()
+            .map(luminance)
+            .fold(f64::INFINITY, f64::min);
+        let maximum = [base, raised, app].into_iter().map(luminance).fold(0., f64::max);
+        if ((minimum + 0.05) / 0.05).max(1.05 / (maximum + 0.05)) < 4.5 {
+            frame.tokens.colors.surface_raised = frame.tokens.colors.surface_base.clone();
+            frame.tokens.colors.application_background = frame.tokens.colors.surface_base.clone();
+        }
+        let surface = rgba(&frame.tokens.colors.surface_base).unwrap();
+        let bar = rgba(&frame.tokens.surface.bar.background).unwrap();
+        let mut opacity = if frame.tokens.material.style == "solid" {
+            1.
+        } else {
+            frame.tokens.material.opacity * frame.tokens.material.tint_strength
+        };
+        for step in 0..=100 {
+            let candidate = opacity + (1. - opacity) * f64::from(step) / 100.;
+            let backgrounds = material_bounds(surface, candidate);
+            let raised = rgba(&frame.tokens.colors.surface_raised).unwrap();
+            let app = rgba(&frame.tokens.colors.application_background).unwrap();
+            let all = [backgrounds[0], backgrounds[1], raised, app];
+            let minimum = all.into_iter().map(luminance).fold(f64::INFINITY, f64::min);
+            let maximum = all.into_iter().map(luminance).fold(0., f64::max);
+            let bar = material_bounds(bar, candidate);
+            let readable = ((minimum + 0.05) / 0.05).max(1.05 / (maximum + 0.05)) >= 4.5
+                && contrast([0., 0., 0., 1.], bar[0]).max(contrast([1.; 4], bar[1])) >= 4.5;
+            if readable {
+                opacity = candidate;
+                break;
+            }
+        }
+        if opacity > frame.tokens.material.opacity {
+            frame.tokens.material.opacity = opacity;
+            frame.tokens.material.tint_strength = 1.;
+        } else if frame.tokens.material.opacity > 0. {
+            frame.tokens.material.tint_strength = opacity / frame.tokens.material.opacity;
+        }
+        let surface = material_bounds(surface, opacity);
+        let bar = material_bounds(bar, opacity);
+        let raised = rgba(&frame.tokens.colors.surface_raised).unwrap();
+        let app = rgba(&frame.tokens.colors.application_background).unwrap();
+        let body_backgrounds = [surface[0], surface[1], raised, app];
+        let body_bounds = [
+            *body_backgrounds
+                .iter()
+                .min_by(|a, b| luminance(**a).total_cmp(&luminance(**b)))
+                .unwrap(),
+            *body_backgrounds
+                .iter()
+                .max_by(|a, b| luminance(**a).total_cmp(&luminance(**b)))
+                .unwrap(),
+        ];
+        frame.tokens.colors.text_primary = hex(material_foreground(
+            rgba(&preferred.tokens.colors.text_primary).unwrap(),
+            body_bounds,
+        ));
+        frame.tokens.colors.text_muted = hex(material_foreground(
+            rgba(&preferred.tokens.colors.text_muted).unwrap(),
+            body_bounds,
+        ));
+        frame.tokens.surface.bar.text_primary = hex(material_foreground(
+            rgba(&preferred.tokens.surface.bar.text_primary).unwrap(),
+            bar,
+        ));
+        frame.tokens.surface.bar.text_muted = hex(material_foreground(
+            rgba(&preferred.tokens.surface.bar.text_muted).unwrap(),
+            bar,
+        ));
+        frame.tokens.colors.on_accent = hex(readable(
+            rgba(&preferred.tokens.colors.on_accent).unwrap(),
+            rgba(&frame.tokens.colors.accent).unwrap(),
+            4.5,
+        ));
+        frame
+    }
+}
diff --git a/crates/ferese-theme-model/src/families.rs b/crates/ferese-theme-model/src/families.rs
new file mode 100644
index 0000000..5375abb
--- /dev/null
+++ b/crates/ferese-theme-model/src/families.rs
@@ -0,0 +1,51 @@
+use serde::{Deserialize, Serialize};
+
+use crate::{Appearance, Tokens};
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Palette {
+    pub background: String,
+    pub bar: String,
+    pub surface: String,
+    pub text: String,
+    pub muted: String,
+    pub accent: String,
+}
+
+impl From<&Tokens> for Palette {
+    fn from(tokens: &Tokens) -> Self {
+        Self {
+            background: tokens.colors.surface_base.clone(),
+            bar: tokens.surface.bar.background.clone(),
+            surface: tokens.colors.surface_raised.clone(),
+            text: tokens.colors.text_primary.clone(),
+            muted: tokens.colors.text_muted.clone(),
+            accent: tokens.colors.accent.clone(),
+        }
+    }
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Family {
+    pub id: String,
+    pub name: String,
+    pub light: Option<Palette>,
+    pub dark: Option<Palette>,
+}
+
+impl Family {
+    pub fn palette(&self, appearance: Appearance) -> Option<&Palette> {
+        match appearance {
+            Appearance::Light => self.light.as_ref(),
+            Appearance::Dark => self.dark.as_ref(),
+        }
+    }
+
+    pub fn availability(&self) -> &'static str {
+        match (self.light.is_some(), self.dark.is_some()) {
+            (true, true) => "light and dark",
+            (true, false) => "light only",
+            _ => "dark only",
+        }
+    }
+}
diff --git a/crates/ferese-theme-model/src/lib.rs b/crates/ferese-theme-model/src/lib.rs
new file mode 100644
index 0000000..cb68099
--- /dev/null
+++ b/crates/ferese-theme-model/src/lib.rs
@@ -0,0 +1,135 @@
+//! Resolved theme values and pure color operations. No configuration or runtime access.
+use serde::{Deserialize, Serialize};
+use std::path::PathBuf;
+mod color;
+pub mod families;
+pub use color::*;
+
+#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "lowercase")]
+pub enum Appearance {
+    Light,
+    #[default]
+    Dark,
+}
+
+#[derive(Clone, Copy, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(rename_all = "lowercase")]
+pub enum Mode {
+    Light,
+    #[default]
+    Dark,
+    Auto,
+}
+
+#[derive(Clone, Debug, Default, Deserialize, Serialize, PartialEq, Eq)]
+#[serde(default)]
+pub struct Accessibility {
+    pub increase_contrast: bool,
+    pub reduce_transparency: bool,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Colors {
+    pub surface_base: String,
+    pub surface_raised: String,
+    pub application_background: String,
+    pub text_primary: String,
+    pub text_muted: String,
+    pub accent: String,
+    pub on_accent: String,
+    pub border: String,
+    pub shadow: String,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Material {
+    pub style: String,
+    pub opacity: f64,
+    pub blur_radius: f64,
+    pub tint_strength: f64,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Geometry {
+    pub border_width: f64,
+    pub focus_ring_width: f64,
+    pub window_radius: f64,
+    pub shell_radius: f64,
+    pub top_bar_height: f64,
+    pub top_bar_margin_top: i32,
+    pub top_bar_margin_horizontal: i32,
+    pub top_bar_window_gap: i32,
+    pub panel_padding: f64,
+    pub control_gap: f64,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Typography {
+    pub font_family: String,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Background {
+    pub path: Option<PathBuf>,
+    pub lock_path: Option<PathBuf>,
+    pub mode: String,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct BarSurface {
+    pub background: String,
+    pub text_primary: String,
+    pub text_muted: String,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Surfaces {
+    pub bar: BarSurface,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct SoftShadow {
+    pub offset_y: f64,
+    pub blur: f64,
+    pub opacity: f64,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Shadows {
+    pub soft: SoftShadow,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Gradient {
+    pub from: String,
+    pub to: String,
+    pub angle: f64,
+}
+
+#[derive(Clone, Debug, Default, Deserialize, Serialize, PartialEq)]
+pub struct Paint {
+    pub gradient: Option<Gradient>,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct Tokens {
+    pub colors: Colors,
+    pub material: Material,
+    pub geometry: Geometry,
+    pub typography: Typography,
+    pub background: Background,
+    pub surface: Surfaces,
+    pub shadow: Shadows,
+    pub border: Paint,
+    pub focus_ring: Paint,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize, PartialEq)]
+pub struct ResolvedTheme {
+    pub appearance: Appearance,
+    pub tokens: Tokens,
+    pub requested_accent: String,
+    pub accessibility: Accessibility,
+    pub reduced_motion: bool,
+}
diff --git a/crates/ferese-theme/src/palette.rs b/crates/ferese-theme/src/palette.rs
index 1ac8a32..54f2138 100644
--- a/crates/ferese-theme/src/palette.rs
+++ b/crates/ferese-theme/src/palette.rs
@@ -168,7 +168,7 @@ mod tests {
             ("translucent", 1., 1.),
             ("translucent", 0., 0.),
         ] {
-            let mut theme = ferese_config::theme::ResolvedTheme::default();
+            let mut theme = ferese_config::theme::default_theme();
             theme.tokens.material.style = style.into();
             theme.tokens.material.opacity = opacity;
             assert_eq!(crate::service::opacity(&theme), expected);
diff --git a/portal/src/settings.rs b/portal/src/settings.rs
index 2600b18..6be146d 100644
--- a/portal/src/settings.rs
+++ b/portal/src/settings.rs
@@ -162,7 +162,7 @@ fn initial_appearance(theme: Option<&ResolvedTheme>, load: impl FnOnce() -> Opti
     theme
         .map(Appearance::from_resolved)
         .or_else(load)
-        .unwrap_or_else(|| Appearance::from_resolved(&ResolvedTheme::default()))
+        .unwrap_or_else(|| Appearance::from_resolved(&ferese_config::theme::default_theme()))
 }
 
 fn read_source(path: &Path) -> Result<String, String> {
@@ -186,7 +186,7 @@ fn load_path(path: &Path) -> Result<Appearance, String> {
     let source = match read_source(path) {
         Ok(source) => source,
         Err(_) if !path.try_exists().map_err(|error| error.to_string())? => {
-            return Ok(Appearance::from_resolved(&ResolvedTheme::default()));
+            return Ok(Appearance::from_resolved(&ferese_config::theme::default_theme()));
         }
         Err(error) => return Err(error),
     };
@@ -222,7 +222,7 @@ mod tests {
         assert_eq!(appearance.contrast, 1);
         assert_ne!(
             appearance.accent,
-            Appearance::from_resolved(&ResolvedTheme::default()).accent
+            Appearance::from_resolved(&ferese_config::theme::default_theme()).accent
         );
 
         std::fs::write(&path, r#"theme { mode "dark"; }; animations { enabled #false; }"#).unwrap();
@@ -248,7 +248,7 @@ mod tests {
     fn disk_fallback_rejects_invalid_config_and_uses_defaults_when_absent() {
         let root = tempfile::tempdir().unwrap();
         let path = root.path().join("config.kdl");
-        let default = Appearance::from_resolved(&ResolvedTheme::default());
+        let default = Appearance::from_resolved(&ferese_config::theme::default_theme());
         assert_eq!(load_path(&path).unwrap(), default);
         for source in [
             r#"theme { broken"#,
diff --git a/scripts/tests/test_component_boundaries.py b/scripts/tests/test_component_boundaries.py
index 9f31f00..b248230 100644
--- a/scripts/tests/test_component_boundaries.py
+++ b/scripts/tests/test_component_boundaries.py
@@ -33,6 +33,13 @@ class ComponentBoundaries(unittest.TestCase):
     def test_shell_does_not_depend_on_core(self):
         self.assertNotIn("ferese-core", reachable(dependency_graph(), "ferese-shell"))
 
+    def test_theme_model_has_no_configuration_or_runtime_dependencies(self):
+        dependencies = reachable(dependency_graph(), "ferese-theme-model")
+        self.assertTrue(dependencies.isdisjoint({
+            "ferese-config", "ferese-ipc", "ferese-theme", "ferese-core",
+            "libcosmic", "wayland-client", "tokio", "kdl", "jiff",
+        }), dependencies)
+
     def test_transitive_dependencies_are_checked(self):
         self.assertIn("core", reachable({"shell": {"helper"}, "helper": {"core"}}, "shell"))
 
diff --git a/shell/ferese-polkit-agent/src/prompt.rs b/shell/ferese-polkit-agent/src/prompt.rs
index 591cb12..b79d230 100644
--- a/shell/ferese-polkit-agent/src/prompt.rs
+++ b/shell/ferese-polkit-agent/src/prompt.rs
@@ -609,7 +609,7 @@ mod tests {
         drop(writer);
         reader_thread.join().unwrap();
         assert!(matches!(incoming.lock().unwrap().back(), Some(PromptEvent::Cancel)));
-        let appearance = Appearance::from_resolved(&ferese_config::theme::ResolvedTheme::default());
+        let appearance = Appearance::from_resolved(&ferese_config::theme::default_theme());
         let (mut prompt, _) = Prompt::init(Core::default(), (incoming, request_fixture(), appearance));
         *prompt.answer = "test-password".into();
         prompt.waiting = false;
@@ -625,7 +625,7 @@ mod tests {
         use crate::{Generation, PromptEvent};
 
         let incoming = Arc::new(Mutex::new(VecDeque::new()));
-        let appearance = Appearance::from_resolved(&ferese_config::theme::ResolvedTheme::default());
+        let appearance = Appearance::from_resolved(&ferese_config::theme::default_theme());
         let (mut prompt, _) = Prompt::init(Core::default(), (incoming.clone(), request_fixture(), appearance));
         assert_eq!(prompt.select_identity(1), Some(1001));
         let older = prompt.request.generation;
@@ -719,7 +719,7 @@ mod tests {
 
     #[test]
     fn selecting_another_account_clears_password_and_waits_for_a_fresh_prompt() {
-        let appearance = Appearance::from_resolved(&ferese_config::theme::ResolvedTheme::default());
+        let appearance = Appearance::from_resolved(&ferese_config::theme::default_theme());
         let (mut prompt, _) = <Prompt as cosmic::Application>::init(
             Core::default(),
             (Arc::new(Mutex::new(VecDeque::new())), request_fixture(), appearance),