diff --git a/compositor/src/presentation.rs b/compositor/src/presentation.rs
index 7ad5dc1..b8642c6 100644
--- a/compositor/src/presentation.rs
+++ b/compositor/src/presentation.rs
@@ -96,6 +96,41 @@ pub(crate) fn physical_rect(
     )
 }
 
+/// A single physical outline shared by content and all of its decorations.
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub(crate) struct RoundedRect {
+    pub rect: Rectangle<i32, Physical>,
+    pub radius: f32,
+}
+
+impl RoundedRect {
+    pub(crate) fn new(rect: ferese_layout::Rect, origin: Point<i32, Logical>, scale: f64, radius: f64) -> Self {
+        let rect = physical_rect(rect, origin, scale);
+        Self {
+            radius: clamp_radius(radius * scale, rect.size),
+            rect,
+        }
+    }
+
+    pub(crate) fn from_logical(rect: Rectangle<i32, Logical>, scale: f64, radius: f64) -> Self {
+        Self::new(
+            ferese_layout::Rect::new(
+                rect.loc.x as f64,
+                rect.loc.y as f64,
+                rect.size.w as f64,
+                rect.size.h as f64,
+            ),
+            (0, 0).into(),
+            scale,
+            radius,
+        )
+    }
+}
+
+pub(crate) fn clamp_radius(requested: f64, size: smithay::utils::Size<i32, Physical>) -> f32 {
+    requested.min(f64::from(size.w.min(size.h)) / 2.0).max(0.0) as f32
+}
+
 pub(crate) fn handoff_alpha(elapsed: Duration) -> f32 {
     let progress = (elapsed.as_secs_f64() / HANDOFF.as_secs_f64()).clamp(0.0, 1.0);
     (1.0 - progress * progress * (3.0 - 2.0 * progress)) as f32
@@ -259,6 +294,51 @@ impl RenderElement<GlesRenderer> for NativeTextureElement {
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn rounded_outline_clamps_after_physical_snapping() {
+        // Logical clamping would give 1.125; the snapped 3px rect allows radius 1.5.
+        let outline = RoundedRect::new(ferese_layout::Rect::new(0.2, 0.2, 1.5, 4.0), (0, 0).into(), 1.5, 20.0);
+        assert_eq!(outline.rect, Rectangle::new((0, 0).into(), (3, 6).into()));
+        assert_eq!(outline.radius, 1.5);
+        for scale in [1.0, 1.25, 1.5, 2.0] {
+            let rect = ferese_layout::Rect::new(-20.4, -10.2, 8.8, 6.4);
+            let outline = RoundedRect::new(rect, (-10, -5).into(), scale, 100.0);
+            assert_eq!(outline.rect, physical_rect(rect, (-10, -5).into(), scale));
+            assert_eq!(
+                outline.radius,
+                outline.rect.size.w.min(outline.rect.size.h) as f32 / 2.0
+            );
+        }
+    }
+
+    #[test]
+    fn physical_radius_preserves_fractions_and_handles_zero() {
+        let size = (11, 7).into();
+        assert_eq!(clamp_radius(100.0, size), 3.5);
+        assert_eq!(clamp_radius(2.25, size), 2.25);
+        assert_eq!(clamp_radius(0.0, size), 0.0);
+        assert_eq!(clamp_radius(-1.0, size), 0.0);
+        assert_eq!(clamp_radius(2.0, (0, 10).into()), 0.0);
+        let outline = RoundedRect::new(ferese_layout::Rect::new(0.0, 0.0, 10.0, 10.0), (0, 0).into(), 1.5, 1.5);
+        assert_eq!(outline.radius, 2.25);
+    }
+
+    #[test]
+    fn material_and_window_outline_agree_for_the_same_rect() {
+        let logical = Rectangle::new((-3, 7).into(), (11, 9).into());
+        for scale in [1.0, 1.25, 1.5, 2.0] {
+            assert_eq!(
+                RoundedRect::from_logical(logical, scale, 100.0),
+                RoundedRect::new(
+                    ferese_layout::Rect::new(-3.0, 7.0, 11.0, 9.0),
+                    (0, 0).into(),
+                    scale,
+                    100.0
+                )
+            );
+        }
+    }
+
     use super::*;
 
     #[test]
diff --git a/compositor/src/render/decorations.rs b/compositor/src/render/decorations.rs
index ea4a9fd..d2f4b1b 100644
--- a/compositor/src/render/decorations.rs
+++ b/compositor/src/render/decorations.rs
@@ -29,9 +29,9 @@ pub(super) fn rounded_clip_program(state: &mut Ferese, renderer: &mut GlesRender
         UniformName::new("opacity", UniformType::_1f),
         UniformName::new("shadow_color", UniformType::_4f),
     ];
-    let texture = renderer.compile_custom_texture_shader(ROUNDED_TEXTURE_SHADER, &texture_uniforms);
-    let border = renderer.compile_custom_pixel_shader(ROUNDED_BORDER_SHADER, &border_uniforms);
-    let shadow = renderer.compile_custom_pixel_shader(WINDOW_SHADOW_SHADER, &shadow_uniforms);
+    let texture = renderer.compile_custom_texture_shader(&corner_shader(ROUNDED_TEXTURE_SHADER), &texture_uniforms);
+    let border = renderer.compile_custom_pixel_shader(&corner_shader(ROUNDED_BORDER_SHADER), &border_uniforms);
+    let shadow = renderer.compile_custom_pixel_shader(&corner_shader(WINDOW_SHADOW_SHADER), &shadow_uniforms);
     let compiled = texture.and_then(|texture| border.and_then(|border| shadow.map(|shadow| (texture, border, shadow))));
     match compiled {
         Ok((texture, border, shadow)) => {
@@ -44,7 +44,9 @@ pub(super) fn rounded_clip_program(state: &mut Ferese, renderer: &mut GlesRender
             Some(programs)
         }
         Err(error) => {
-            tracing::error!(%error, "failed to compile rounded-window shader");
+            if state.rounded_clip_warnings.insert(context) {
+                tracing::warn!(%error, "rounded-window shader unavailable; falling back to unrounded rendering");
+            }
             None
         }
     }
@@ -56,9 +58,8 @@ pub(super) fn window_border_element(
     renderer: &GlesRenderer,
     id: ferese_layout::WindowId,
     geometry: Rectangle<i32, Logical>,
-    physical: Rectangle<i32, Physical>,
+    corners: RoundedRect,
     scale: f64,
-    requested_radius: f64,
     requested_width: f64,
     color: [f32; 4],
     gradient: Option<crate::config::BorderGradient>,
@@ -68,7 +69,7 @@ pub(super) fn window_border_element(
     programs: &RoundedClipPrograms,
 ) -> Option<PhysicalShaderElement> {
     let mode = output.current_mode()?;
-    let width = scaled_effect_value(requested_width, geometry, scale);
+    let width = clamp_radius(requested_width * scale, corners.rect.size);
     if width == 0.0 {
         return None;
     }
@@ -77,7 +78,12 @@ pub(super) fn window_border_element(
         Some(gradient) => (
             gradient.from.0,
             gradient.to.0,
-            border_gradient_line(physical, mode.size, output.current_transform().invert(), gradient.angle),
+            border_gradient_line(
+                corners.rect,
+                mode.size,
+                output.current_transform().invert(),
+                gradient.angle,
+            ),
         ),
         None => (color, color, [0.0; 4]),
     };
@@ -85,7 +91,7 @@ pub(super) fn window_border_element(
         Some(g) => (
             g.from.0,
             g.to.0,
-            border_gradient_line(physical, mode.size, output.current_transform().invert(), g.angle),
+            border_gradient_line(corners.rect, mode.size, output.current_transform().invert(), g.angle),
         ),
         None => (
             state.theme_settings.accent_color.0,
@@ -95,8 +101,8 @@ pub(super) fn window_border_element(
     };
     let parameters = BorderParameters {
         geometry,
-        clip_rect: framebuffer_clip_rect(physical, mode.size, output.current_transform().invert()),
-        radius: scaled_effect_value(requested_radius, geometry, scale),
+        clip_rect: framebuffer_clip_rect(corners.rect, mode.size, output.current_transform().invert()),
+        radius: corners.radius,
         width,
         color: color_with_alpha(from, opacity),
         color_to: color_with_alpha(to, opacity),
@@ -137,7 +143,7 @@ pub(super) fn window_border_element(
 
     Some(PhysicalShaderElement {
         inner: cached.element.clone(),
-        geometry: physical,
+        geometry: corners.rect,
     })
 }
 
@@ -162,9 +168,7 @@ pub(super) fn window_tint_element(
     renderer: &mut GlesRenderer,
     id: ferese_layout::WindowId,
     geometry: Rectangle<i32, Logical>,
-    physical: Rectangle<i32, Physical>,
-    scale: f64,
-    radius: f64,
+    corners: RoundedRect,
     color: [f32; 4],
     resize_fill: bool,
     output: &Output,
@@ -181,8 +185,8 @@ pub(super) fn window_tint_element(
     let program = material_program(state, renderer)?;
     let parameters = BorderParameters {
         geometry,
-        clip_rect: framebuffer_clip_rect(physical, mode.size, output.current_transform().invert()),
-        radius: scaled_effect_value(radius, geometry, scale),
+        clip_rect: framebuffer_clip_rect(corners.rect, mode.size, output.current_transform().invert()),
+        radius: corners.radius,
         width: 0.0,
         color,
         color_to: color,
@@ -230,7 +234,7 @@ pub(super) fn window_tint_element(
     }
     Some(PhysicalShaderElement {
         inner: cached.element.clone(),
-        geometry: physical,
+        geometry: corners.rect,
     })
 }
 
@@ -240,9 +244,8 @@ pub(super) fn window_shadow_element(
     renderer: &GlesRenderer,
     id: ferese_layout::WindowId,
     geometry: Rectangle<i32, Logical>,
-    physical: Rectangle<i32, Physical>,
+    corners: RoundedRect,
     scale: f64,
-    requested_radius: f64,
     offset_y: f64,
     blur: f64,
     opacity: f64,
@@ -256,15 +259,19 @@ pub(super) fn window_shadow_element(
     }
 
     let shadow_geometry = Rectangle::new(
-        (physical.loc.x, physical.loc.y + (offset_y * scale).round() as i32).into(),
-        physical.size,
+        (
+            corners.rect.loc.x,
+            corners.rect.loc.y + (offset_y * scale).round() as i32,
+        )
+            .into(),
+        corners.rect.size,
     );
     let bounds = shadow_bounds(geometry, offset_y, blur);
     let parameters = ShadowParameters {
         blur: (blur * scale) as f32,
         bounds,
         shadow_rect: framebuffer_clip_rect(shadow_geometry, mode.size, output.current_transform().invert()),
-        radius: scaled_effect_value(requested_radius, geometry, scale),
+        radius: corners.radius,
         opacity: opacity as f32,
         color,
     };
@@ -327,21 +334,12 @@ pub(super) fn shadow_bounds(geometry: Rectangle<i32, Logical>, offset_y: f64, bl
     )
 }
 
-pub(super) fn scaled_effect_value(requested: f64, geometry: Rectangle<i32, Logical>, scale: f64) -> f32 {
-    requested
-        .min(f64::from(geometry.size.w.min(geometry.size.h)) / 2.0)
-        .max(0.0) as f32
-        * scale as f32
-}
-
 #[allow(clippy::too_many_arguments)]
 pub(super) fn rounded_window_elements(
     renderer: &mut GlesRenderer,
     window: &smithay::desktop::Window,
-    constrain: Rectangle<i32, Logical>,
-    physical_constrain: Rectangle<i32, Physical>,
+    corners: RoundedRect,
     scale: f64,
-    requested_radius: f64,
     alpha: f32,
     clip_changed: bool,
     output: &Output,
@@ -355,11 +353,12 @@ pub(super) fn rounded_window_elements(
         return Vec::new();
     };
 
+    let physical_constrain = corners.rect;
     let geometry = window.geometry();
     let reference = geometry.to_physical_precise_round(scale);
     let location = physical_constrain.loc - geometry.loc.to_physical_precise_round(scale);
     let clip = framebuffer_clip_rect(physical_constrain, mode.size, output.current_transform().invert());
-    let radius = scaled_effect_value(requested_radius, constrain, scale);
+    let radius = corners.radius;
     let surface = toplevel.wl_surface();
 
     let mut content = PopupManager::popups_for_surface(surface)
diff --git a/compositor/src/render/materials.rs b/compositor/src/render/materials.rs
index a7e5b2c..ce388f7 100644
--- a/compositor/src/render/materials.rs
+++ b/compositor/src/render/materials.rs
@@ -33,10 +33,14 @@ pub(super) fn append_material_surface(
             })
             .collect(),
     };
+    let targets: Vec<_> = targets
+        .into_iter()
+        .map(|(rect, radius)| (rect, RoundedRect::from_logical(rect, scale, f64::from(radius))))
+        .collect();
     let materials: Vec<_> = targets
         .iter()
         .enumerate()
-        .filter_map(|(index, (rect, radius))| {
+        .filter_map(|(index, (rect, corners))| {
             material_element(
                 state,
                 renderer,
@@ -44,7 +48,7 @@ pub(super) fn append_material_surface(
                 surface,
                 MaterialSurface {
                     geometry: *rect,
-                    radius: *radius,
+                    corners: *corners,
                     index,
                     capture_geometry: geometry,
                     alpha: 1.0,
@@ -57,16 +61,13 @@ pub(super) fn append_material_surface(
     }
     let material = (!materials.is_empty() && regions.is_none()).then_some(());
     let clip = material.as_ref().and_then(|_| {
+        let corners = targets.first()?.1;
         let mode = output.current_mode()?;
         let program = rounded_clip_program(state, renderer)?;
         Some((
             program.texture,
-            framebuffer_clip_rect(
-                geometry.to_physical_precise_round(scale),
-                mode.size,
-                output.current_transform().invert(),
-            ),
-            scaled_effect_value(radius, geometry, scale),
+            framebuffer_clip_rect(corners.rect, mode.size, output.current_transform().invert()),
+            corners.radius,
         ))
     });
     // Smithay element lists are front to back: content, material, shadow.
@@ -103,7 +104,7 @@ pub(super) fn append_material_surface(
 
 pub(super) struct MaterialSurface {
     pub geometry: Rectangle<i32, Logical>,
-    pub radius: f32,
+    pub corners: RoundedRect,
     pub index: usize,
     pub capture_geometry: Rectangle<i32, Logical>,
     pub alpha: f32,
@@ -118,7 +119,7 @@ pub(super) fn material_element(
 ) -> Option<(AnimatedWindowRenderElement, AnimatedWindowRenderElement)> {
     let MaterialSurface {
         geometry,
-        radius,
+        corners,
         index,
         capture_geometry,
         alpha,
@@ -139,7 +140,7 @@ pub(super) fn material_element(
         state.theme_settings.surface_base_color
     };
     let [red, green, blue, _] = background.0;
-    let radius = radius.min(geometry.size.w.min(geometry.size.h) as f32 * 0.5);
+    let radius = corners.radius;
     let [offset_y, shadow_blur, shadow_opacity] = material.shadow;
     let edge_bar = role == crate::effects::SemanticRole::Panel && radius == 0.0 && geometry.loc.y == 0;
     let shadow_opacity = if edge_bar {
@@ -148,8 +149,12 @@ pub(super) fn material_element(
         shadow_opacity * (state.theme_settings.shadow_opacity / 0.2) * f64::from(presentation_alpha)
     };
     let shadow_geometry = Rectangle::new(
-        (geometry.loc.x, geometry.loc.y + offset_y.round() as i32).into(),
-        geometry.size,
+        (
+            corners.rect.loc.x,
+            corners.rect.loc.y + (offset_y * scale).round() as i32,
+        )
+            .into(),
+        corners.rect.size,
     );
     let background_opacity = material.opacity;
     let blur = material_blur_radius(material.style, material.opacity, state.theme_settings.backdrop_blur);
@@ -169,15 +174,15 @@ pub(super) fn material_element(
         sample_geometry,
         sample_physical,
         sample_framebuffer: framebuffer_clip_rect(sample_physical, mode.size, transform),
-        radius: radius * scale as f32,
-        shadow_rect: framebuffer_clip_rect(shadow_geometry.to_physical_precise_round(scale), mode.size, transform),
+        radius,
+        shadow_rect: framebuffer_clip_rect(shadow_geometry, mode.size, transform),
         shadow_values: [(shadow_blur * scale) as f32, shadow_opacity as f32],
         shadow_bounds: shadow_bounds(geometry, offset_y, shadow_blur),
         geometry,
         tint: [red, green, blue, material.opacity * presentation_alpha],
         generation,
         opaque: material.opacity == 1.0 && presentation_alpha == 1.0 && radius == 0.0,
-        visible_framebuffer: framebuffer_clip_rect(geometry.to_physical_precise_round(scale), mode.size, transform),
+        visible_framebuffer: framebuffer_clip_rect(corners.rect, mode.size, transform),
     };
     let context = renderer.context_id().erased();
     let program = material_program(state, renderer)?;
@@ -281,7 +286,14 @@ pub(super) fn material_element(
         cached.parameters = parameters;
     }
     let background = match &cached.element {
-        MaterialElement::Fill(element) => element.clone().into(),
+        // Keep the shader's opaque regions when its canvas already has the
+        // shared edges. Animated modal geometry may need a physical override.
+        MaterialElement::Fill(element) if element.geometry(scale.into()) == corners.rect => element.clone().into(),
+        MaterialElement::Fill(element) => PhysicalShaderElement {
+            inner: element.clone(),
+            geometry: corners.rect,
+        }
+        .into(),
         MaterialElement::Blur(element) => element.clone().into(),
     };
     Some((background, cached.shadow.clone().into()))
@@ -300,7 +312,7 @@ pub(super) fn blur_program(state: &mut Ferese, renderer: &mut GlesRenderer) -> O
     if let Some(program) = state.blur_programs.get(&context) {
         return Some(program.clone());
     }
-    match renderer.compile_custom_texture_shader(BLUR_SHADER, &blur_uniform_names()) {
+    match renderer.compile_custom_texture_shader(&corner_shader(BLUR_SHADER), &blur_uniform_names()) {
         Ok(program) => {
             let program = BlurProgram(program);
             state.blur_programs.insert(context, program.clone());
@@ -372,7 +384,7 @@ pub(super) fn material_program(state: &mut Ferese, renderer: &mut GlesRenderer)
         UniformName::new("shadow_rect", UniformType::_4f),
         UniformName::new("shadow_values", UniformType::_2f),
     ];
-    match renderer.compile_custom_pixel_shader(MATERIAL_SHADER, &uniforms) {
+    match renderer.compile_custom_pixel_shader(&corner_shader(MATERIAL_SHADER), &uniforms) {
         Ok(program) => {
             let program = MaterialProgram(program);
             state.material_programs.insert(context, program.clone());
diff --git a/compositor/src/render/mod.rs b/compositor/src/render/mod.rs
index 0ef04d0..f76f0f1 100644
--- a/compositor/src/render/mod.rs
+++ b/compositor/src/render/mod.rs
@@ -48,7 +48,7 @@ use smithay::wayland::shell::wlr_layer::Layer;
 
 use crate::Ferese;
 use crate::metrics::FrameEffectMetrics;
-use crate::presentation::{NativeTextureElement, PhysicalShaderElement, physical_rect};
+use crate::presentation::{NativeTextureElement, PhysicalShaderElement, RoundedRect, clamp_radius, physical_rect};
 
 type SurfaceRenderElement =
     CropRenderElement<RelocateRenderElement<RescaleRenderElement<WaylandSurfaceRenderElement<GlesRenderer>>>>;
@@ -106,6 +106,10 @@ const MATERIAL_SHADER: &str = include_str!("shaders/material_shader.frag");
 
 const BLUR_SHADER: &str = include_str!("shaders/blur_shader.frag");
 
+fn corner_shader(source: &str) -> String {
+    source.replace("//_CORNERS_", include_str!("shaders/corners.glsl"))
+}
+
 #[derive(Clone, Debug)]
 pub(crate) struct BlurProgram(GlesTexProgram);
 
@@ -510,6 +514,31 @@ mod tests {
         scaled_visual_rect, shadow_bounds,
     };
 
+    #[test]
+    #[ignore = "requires an EGL rendering device"]
+    fn shared_corner_shaders_compile() {
+        use smithay::backend::egl::{EGLContext, EGLDevice, EGLDisplay};
+        use smithay::backend::renderer::gles::GlesRenderer;
+        let device = EGLDevice::enumerate().unwrap().last().expect("an EGL device");
+        let display = unsafe { EGLDisplay::new(device).unwrap() };
+        let context = EGLContext::new(&display).unwrap();
+        let mut renderer = unsafe { GlesRenderer::new(context).unwrap() };
+        for source in [super::ROUNDED_TEXTURE_SHADER, super::BLUR_SHADER] {
+            renderer
+                .compile_custom_texture_shader(&super::corner_shader(source), &[])
+                .unwrap();
+        }
+        for source in [
+            super::ROUNDED_BORDER_SHADER,
+            super::WINDOW_SHADOW_SHADER,
+            super::MATERIAL_SHADER,
+        ] {
+            renderer
+                .compile_custom_pixel_shader(&super::corner_shader(source), &[])
+                .unwrap();
+        }
+    }
+
     #[test]
     #[ignore = "requires an EGL rendering device"]
     fn translucent_blur_does_not_leak_the_sharp_backdrop() {
@@ -523,7 +552,7 @@ mod tests {
         let context = EGLContext::new(&display).unwrap();
         let mut renderer = unsafe { GlesRenderer::new(context).unwrap() };
         let program = renderer
-            .compile_custom_texture_shader(super::BLUR_SHADER, &super::blur_uniform_names())
+            .compile_custom_texture_shader(&super::corner_shader(super::BLUR_SHADER), &super::blur_uniform_names())
             .unwrap();
         let size = (32, 32).into();
         let mut pixels = vec![128u8; 32 * 32 * 4];
diff --git a/compositor/src/render/overview.rs b/compositor/src/render/overview.rs
index f259571..9628c44 100644
--- a/compositor/src/render/overview.rs
+++ b/compositor/src/render/overview.rs
@@ -15,12 +15,12 @@ pub(super) fn overview_chrome_element(
 ) -> Option<PhysicalShaderElement> {
     let output_id = state.output_id(output)?;
     let geometry = rounded_visual_rect(rect, output_geometry.loc);
-    let physical = physical_rect(rect, output_geometry.loc, scale);
+    let corners = RoundedRect::new(rect, output_geometry.loc, scale, radius);
     let mode = output.current_mode()?;
     let parameters = BorderParameters {
         geometry,
-        clip_rect: framebuffer_clip_rect(physical, mode.size, output.current_transform().invert()),
-        radius: (radius * scale) as f32,
+        clip_rect: framebuffer_clip_rect(corners.rect, mode.size, output.current_transform().invert()),
+        radius: corners.radius,
         width: (width * scale) as f32,
         color,
         color_to: color,
@@ -79,7 +79,7 @@ pub(super) fn overview_chrome_element(
     }
     Some(PhysicalShaderElement {
         inner: cached.element.clone(),
-        geometry: physical,
+        geometry: corners.rect,
     })
 }
 
@@ -223,10 +223,8 @@ pub(super) fn overview_strip_elements(
                     elements.extend(rounded_window_elements(
                         renderer,
                         window,
-                        rounded_visual_rect(*rect, output_geometry.loc),
-                        physical_rect(*rect, output_geometry.loc, scale),
+                        RoundedRect::new(*rect, output_geometry.loc, scale, 4.0),
                         scale,
-                        4.0,
                         alpha,
                         true,
                         output,
diff --git a/compositor/src/render/scene.rs b/compositor/src/render/scene.rs
index 4473156..b4b76f4 100644
--- a/compositor/src/render/scene.rs
+++ b/compositor/src/render/scene.rs
@@ -136,7 +136,6 @@ pub(crate) fn output_elements(
 
     for (window, id, visual, decoration_progress, close_alpha) in windows {
         let constrain = rounded_visual_rect(visual, output_geometry.loc);
-        let pixels = physical_rect(visual, output_geometry.loc, scale);
         let material_surface = window
             .toplevel()
             .map(|toplevel| toplevel.wl_surface())
@@ -149,6 +148,8 @@ pub(crate) fn output_elements(
         } else {
             state.theme_settings.window_radius
         } * decoration_progress;
+        let corners = RoundedRect::new(visual, output_geometry.loc, scale, window_radius);
+        let pixels = corners.rect;
         // Only overview/close intentionally scale the complete application.
         let scale_content = state.overview.is_presenting() || state.closing_visual(id).0 != 1.0;
         let behavior = resize_content_behavior(scale_content);
@@ -159,9 +160,7 @@ pub(crate) fn output_elements(
             renderer,
             id,
             constrain,
-            pixels,
-            scale,
-            window_radius,
+            corners,
             [0.0, 0.0, 0.0, dim as f32 * close_alpha],
             false,
             output,
@@ -195,9 +194,8 @@ pub(crate) fn output_elements(
                 renderer,
                 id,
                 constrain,
-                pixels,
+                corners,
                 scale,
-                window_radius,
                 border_width,
                 border_color,
                 gradient,
@@ -213,9 +211,8 @@ pub(crate) fn output_elements(
                 renderer,
                 id,
                 constrain,
-                pixels,
+                corners,
                 scale,
-                window_radius,
                 shadow_offset_y,
                 shadow_blur,
                 shadow_opacity * f64::from(close_alpha) * decoration_progress,
@@ -250,8 +247,7 @@ pub(crate) fn output_elements(
                             program: Some(programs.texture.clone()),
                             uniforms: vec![
                                 Uniform::new("clip_rect", clip).into_owned(),
-                                Uniform::new("radius", scaled_effect_value(window_radius, constrain, scale))
-                                    .into_owned(),
+                                Uniform::new("radius", corners.radius).into_owned(),
                             ],
                         }
                         .into(),
@@ -261,10 +257,8 @@ pub(crate) fn output_elements(
             elements.extend(rounded_window_elements(
                 renderer,
                 &window,
-                constrain,
-                pixels,
+                corners,
                 scale,
-                window_radius,
                 close_alpha,
                 state
                     .window_geometry
@@ -281,18 +275,7 @@ pub(crate) fn output_elements(
             {
                 let mut color = state.theme_settings.surface_base_color.0;
                 color[3] = close_alpha;
-                if let Some(fill) = window_tint_element(
-                    state,
-                    renderer,
-                    id,
-                    constrain,
-                    pixels,
-                    scale,
-                    window_radius,
-                    color,
-                    true,
-                    output,
-                ) {
+                if let Some(fill) = window_tint_element(state, renderer, id, constrain, corners, color, true, output) {
                     // Front-to-back: fill uncovered strips behind the native
                     // content instead of stretching it or exposing wallpaper.
                     elements.push(fill.into());
@@ -308,7 +291,7 @@ pub(crate) fn output_elements(
                     surface,
                     MaterialSurface {
                         geometry: constrain,
-                        radius: window_radius as f32,
+                        corners,
                         index: 0,
                         capture_geometry: constrain,
                         alpha: close_alpha,
diff --git a/compositor/src/render/shaders/blur_shader.frag b/compositor/src/render/shaders/blur_shader.frag
index cd45a95..e7c1063 100644
--- a/compositor/src/render/shaders/blur_shader.frag
+++ b/compositor/src/render/shaders/blur_shader.frag
@@ -19,11 +19,11 @@ uniform float presentation_alpha;
 uniform float background_opacity;
 uniform vec4 tint;
 varying vec2 v_coords;
+//_CORNERS_
+
 void main() {
-    vec2 half_size = visible_rect.zw * 0.5;
-    vec2 d = abs(gl_FragCoord.xy - visible_rect.xy - half_size) - (half_size - vec2(material_radius));
-    float sdf = length(max(d, 0.0)) + min(max(d.x, d.y), 0.0) - material_radius;
-    float coverage = alpha * presentation_alpha * (1.0 - smoothstep(-0.5, 0.5, sdf));
+    float sdf = rounded_rect_distance(gl_FragCoord.xy, visible_rect, material_radius);
+    float coverage = alpha * presentation_alpha * edge_coverage(sdf);
     if (coverage <= 0.0) { gl_FragColor = vec4(0.0); return; }
     vec2 coords = (gl_FragCoord.xy - capture_origin) / texture_size;
     vec4 color = vec4(0.0);
diff --git a/compositor/src/render/shaders/corners.glsl b/compositor/src/render/shaders/corners.glsl
new file mode 100644
index 0000000..c7dd456
--- /dev/null
+++ b/compositor/src/render/shaders/corners.glsl
@@ -0,0 +1,10 @@
+// Coordinates and radius are physical pixels. Rust clamps the outer radius.
+float rounded_rect_distance(vec2 point, vec4 rect, float radius) {
+    vec2 half_size = rect.zw * 0.5;
+    vec2 d = abs(point - rect.xy - half_size) - (half_size - vec2(radius));
+    return length(max(d, 0.0)) + min(max(d.x, d.y), 0.0) - radius;
+}
+
+float edge_coverage(float distance) {
+    return 1.0 - smoothstep(-0.5, 0.5, distance);
+}
diff --git a/compositor/src/render/shaders/material_shader.frag b/compositor/src/render/shaders/material_shader.frag
index 27e401e..4e5603e 100644
--- a/compositor/src/render/shaders/material_shader.frag
+++ b/compositor/src/render/shaders/material_shader.frag
@@ -9,17 +9,13 @@ uniform vec4 shadow_rect;
 uniform vec2 shadow_values;
 varying vec2 v_coords;
 
-float rounded_distance(vec2 point, vec4 rect) {
-    vec2 half_size = rect.zw * 0.5;
-    float radius = min(material_radius, min(half_size.x, half_size.y));
-    vec2 d = abs(point - rect.xy - half_size) - (half_size - vec2(radius));
-    return length(max(d, 0.0)) + min(max(d.x, d.y), 0.0) - radius;
-}
+//_CORNERS_
+
 void main() {
-    float sdf = rounded_distance(gl_FragCoord.xy, visible_rect);
-    float coverage = 1.0 - smoothstep(-0.5, 0.5, sdf);
+    float sdf = rounded_rect_distance(gl_FragCoord.xy, visible_rect, material_radius);
+    float coverage = edge_coverage(sdf);
     if (paint_mode > 0.5) {
-        float distance = max(rounded_distance(gl_FragCoord.xy, shadow_rect), 0.0);
+        float distance = max(rounded_rect_distance(gl_FragCoord.xy, shadow_rect, material_radius), 0.0);
         float sigma = max(shadow_values.x * 0.5, 0.5);
         float opacity = exp(-0.5 * distance * distance / (sigma * sigma))
             * shadow_values.y * (1.0 - coverage) * alpha;
diff --git a/compositor/src/render/shaders/rounded_border_shader.frag b/compositor/src/render/shaders/rounded_border_shader.frag
index 4728db1..34dcd9d 100644
--- a/compositor/src/render/shaders/rounded_border_shader.frag
+++ b/compositor/src/render/shaders/rounded_border_shader.frag
@@ -18,23 +18,16 @@ varying vec2 v_coords;
 uniform float tint;
 #endif
 
-void main() {
-    vec2 point = gl_FragCoord.xy - clip_rect.xy;
-    vec2 half_size = clip_rect.zw * 0.5;
-    vec2 distance = abs(point - half_size) - (half_size - vec2(radius));
-    float signed_distance = length(max(distance, 0.0))
-        + min(max(distance.x, distance.y), 0.0)
-        - radius;
-    float outer_coverage = 1.0 - smoothstep(-0.5, 0.5, signed_distance);
+//_CORNERS_
 
-    vec2 inner_half_size = max(half_size - vec2(border_width), vec2(0.0));
+void main() {
+    float signed_distance = rounded_rect_distance(gl_FragCoord.xy, clip_rect, radius);
+    float outer_coverage = edge_coverage(signed_distance);
+
+    vec2 inner_size = max(clip_rect.zw - vec2(2.0 * border_width), vec2(0.0));
+    vec4 inner_rect = vec4(clip_rect.xy + (clip_rect.zw - inner_size) * 0.5, inner_size);
     float inner_radius = max(radius - border_width, 0.0);
-    vec2 inner_distance = abs(point - half_size)
-        - (inner_half_size - vec2(inner_radius));
-    float inner_signed_distance = length(max(inner_distance, 0.0))
-        + min(max(inner_distance.x, inner_distance.y), 0.0)
-        - inner_radius;
-    float inner_coverage = 1.0 - smoothstep(-0.5, 0.5, inner_signed_distance);
+    float inner_coverage = edge_coverage(rounded_rect_distance(gl_FragCoord.xy, inner_rect, inner_radius));
     float coverage = max(outer_coverage - inner_coverage, 0.0);
     float progress = clamp(dot(gl_FragCoord.xy - gradient_line.xy, gradient_line.zw), 0.0, 1.0);
     // Interpolate premultiplied endpoints: a transparent endpoint must not
diff --git a/compositor/src/render/shaders/rounded_texture_shader.frag b/compositor/src/render/shaders/rounded_texture_shader.frag
index f27c82a..ef93e88 100644
--- a/compositor/src/render/shaders/rounded_texture_shader.frag
+++ b/compositor/src/render/shaders/rounded_texture_shader.frag
@@ -22,6 +22,8 @@ varying vec2 v_coords;
 uniform float tint;
 #endif
 
+//_CORNERS_
+
 void main() {
     vec4 color = texture2D(tex, v_coords);
 
@@ -31,13 +33,8 @@ void main() {
     color = color * alpha;
 #endif
 
-    vec2 point = gl_FragCoord.xy - clip_rect.xy;
-    vec2 half_size = clip_rect.zw * 0.5;
-    vec2 distance = abs(point - half_size) - (half_size - vec2(radius));
-    float signed_distance = length(max(distance, 0.0))
-        + min(max(distance.x, distance.y), 0.0)
-        - radius;
-    float coverage = 1.0 - smoothstep(-0.5, 0.5, signed_distance);
+    float signed_distance = rounded_rect_distance(gl_FragCoord.xy, clip_rect, radius);
+    float coverage = edge_coverage(signed_distance);
     color *= coverage;
 
 #if defined(DEBUG_FLAGS)
diff --git a/compositor/src/render/shaders/window_shadow_shader.frag b/compositor/src/render/shaders/window_shadow_shader.frag
index ac8b45a..b4380da 100644
--- a/compositor/src/render/shaders/window_shadow_shader.frag
+++ b/compositor/src/render/shaders/window_shadow_shader.frag
@@ -13,13 +13,10 @@ varying vec2 v_coords;
 uniform float tint;
 #endif
 
+//_CORNERS_
+
 void main() {
-    vec2 point = gl_FragCoord.xy - shadow_rect.xy;
-    vec2 half_size = shadow_rect.zw * 0.5;
-    vec2 distance = abs(point - half_size) - (half_size - vec2(radius));
-    float signed_distance = length(max(distance, 0.0))
-        + min(max(distance.x, distance.y), 0.0)
-        - radius;
+    float signed_distance = rounded_rect_distance(gl_FragCoord.xy, shadow_rect, radius);
     float sigma = max(blur * 0.5, 0.5);
     float normalized_distance = max(signed_distance, 0.0) / sigma;
     float coverage = exp(-0.5 * normalized_distance * normalized_distance);
diff --git a/compositor/src/state.rs b/compositor/src/state.rs
index 95a3cc3..c415773 100644
--- a/compositor/src/state.rs
+++ b/compositor/src/state.rs
@@ -346,6 +346,7 @@ pub struct Ferese {
     pub(crate) window_dimming: HashMap<WindowId, DimAnimation>,
     pub(crate) window_focus: HashMap<WindowId, DimAnimation>,
     pub(crate) window_shadows: HashMap<WindowId, WindowShadowBuffers>,
+    pub(crate) rounded_clip_warnings: HashSet<ErasedContextId>,
     pub(crate) rounded_clip_programs: HashMap<ErasedContextId, RoundedClipPrograms>,
     pub(crate) overview_scrims: HashMap<OutputId, OverviewScrim>,
     pub(crate) material_programs: HashMap<ErasedContextId, MaterialProgram>,
@@ -581,6 +582,7 @@ impl Ferese {
             window_focus: HashMap::new(),
             window_shadows: HashMap::new(),
             rounded_clip_programs: HashMap::new(),
+            rounded_clip_warnings: HashSet::new(),
             overview_scrims: HashMap::new(),
             material_programs: HashMap::new(),
             material_buffers: HashMap::new(),
diff --git a/crates/ferese-config/src/theme.rs b/crates/ferese-config/src/theme.rs
index f3be80c..28dd3c1 100644
--- a/crates/ferese-config/src/theme.rs
+++ b/crates/ferese-config/src/theme.rs
@@ -604,6 +604,9 @@ pub fn resolve_with_context(
             *path = theme_path(directory, path);
         }
         validate(&tokens)?;
+        // Effects regions encode integer logical radii; publish the same value
+        // to the shell and compositor, without rewriting the authored config.
+        tokens.geometry.shell_radius = tokens.geometry.shell_radius.round();
         let requested_accent = tokens.colors.accent.clone();
         transform(&mut tokens, &policy.accessibility, &mut warnings);
         let theme = ResolvedTheme {
@@ -1297,6 +1300,22 @@ pub fn import_family(id: &str, source: &str) -> Result<ImportedFamily, String> {
 
 #[cfg(test)]
 mod tests {
+    #[test]
+    fn resolved_shell_radius_matches_integer_effect_regions() {
+        for (requested, expected) in [(0.0, 0.0), (0.4, 0.0), (13.4, 13.0), (13.5, 14.0)] {
+            let document = crate::Document::parse(&format!(
+                "theme {{ geometry {{ shell-radius {requested}; window-radius 7.25; }} }}"
+            ))
+            .unwrap();
+            let result = super::resolve(&document, std::path::Path::new("/tmp"), jiff::Timestamp::now(), |_| {
+                Err("unexpected theme file".into())
+            })
+            .unwrap();
+            assert_eq!(result.theme.tokens.geometry.shell_radius, expected);
+            assert_eq!(result.theme.tokens.geometry.window_radius, 7.25);
+        }
+    }
+
     use super::*;
 
     fn candidate(source: &str) -> Result<Candidate, String> {
diff --git a/crates/ferese-theme/src/geometry.rs b/crates/ferese-theme/src/geometry.rs
new file mode 100644
index 0000000..629a2b2
--- /dev/null
+++ b/crates/ferese-theme/src/geometry.rs
@@ -0,0 +1,19 @@
+/// Radius of a concentric inset, in the same units as the outer radius.
+pub fn inner_radius(outer: f32, padding: f32) -> f32 {
+    (outer - padding).max(0.0)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn inset_corners_preserve_the_center_and_saturate() {
+        assert_eq!(inner_radius(14.0, 4.0), 10.0);
+        assert_eq!(inner_radius(7.5, 2.25), 5.25);
+        assert_eq!(inner_radius(14.0, 0.0), 14.0);
+        assert_eq!(inner_radius(14.0, 14.0), 0.0);
+        assert_eq!(inner_radius(14.0, 20.0), 0.0);
+        assert_eq!(inner_radius(0.0, 4.0), 0.0);
+    }
+}
diff --git a/crates/ferese-theme/src/lib.rs b/crates/ferese-theme/src/lib.rs
index 56d6dea..09ca02d 100644
--- a/crates/ferese-theme/src/lib.rs
+++ b/crates/ferese-theme/src/lib.rs
@@ -4,6 +4,7 @@ pub mod calendar;
 mod contrast;
 pub mod controls;
 pub mod gallery;
+mod geometry;
 pub mod icons;
 pub mod material;
 pub mod menus;
@@ -14,6 +15,7 @@ mod typography;
 
 pub use button::accent_button;
 pub use contrast::{accent_color, accent_pair, apply, composite, contrast, foreground, luminance};
+pub use geometry::inner_radius;
 pub use palette::{Palette, mix, parse_color, surface_shade};
 pub use presets::{PRESETS, Preset};
 pub use typography::{font, text};
diff --git a/crates/ferese-theme/src/menus.rs b/crates/ferese-theme/src/menus.rs
index 4a62ed9..2fa268e 100644
--- a/crates/ferese-theme/src/menus.rs
+++ b/crates/ferese-theme/src/menus.rs
@@ -78,20 +78,25 @@ pub fn separator<'a, M: 'a>(foreground: Color, opacity: f32) -> Element<'a, M> {
 
 pub fn switch<'a, M: 'a>(enabled: bool, palette: crate::Palette, opacity: f32) -> Element<'a, M> {
     let (track, thumb) = crate::controls::switch_colors(palette, enabled, false);
+    let track_radius = 10.;
+    let padding = 2.;
     let knob = container(cosmic::widget::Space::new().width(16).height(16))
         .width(16)
         .height(16)
-        .class(crate::controls::surface(Color { a: opacity, ..thumb }, 8.));
+        .class(crate::controls::surface(
+            Color { a: opacity, ..thumb },
+            crate::inner_radius(track_radius, padding),
+        ));
     container(knob)
         .width(36)
         .height(20)
-        .padding(2)
+        .padding(padding)
         .align_x(if enabled {
             cosmic::iced::alignment::Horizontal::Right
         } else {
             cosmic::iced::alignment::Horizontal::Left
         })
-        .class(crate::controls::surface(track.scale_alpha(opacity), 10.))
+        .class(crate::controls::surface(track.scale_alpha(opacity), track_radius))
         .into()
 }
 
diff --git a/docs/configuration.md b/docs/configuration.md
index c2ec7c9..1c53a30 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -183,7 +183,7 @@ Filled controls choose a contrasting text color automatically.
 | `border-width` | number ≥ 0 | `1` | Window border thickness |
 | `focus-ring-width` | number ≥ 0 | `2` | Focused border thickness |
 | `window-radius` | number ≥ 0 | `14` | Managed-window corners, independent of the shell |
-| `shell-radius` | number ≥ 0 | `14` | All shell surfaces, cards, widgets and interaction backgrounds; 0 makes them square |
+| `shell-radius` | number ≥ 0 | `14` | All shell surfaces, cards, widgets and interaction backgrounds; rounded to the nearest logical pixel to match blur regions; 0 makes them square |
 | `top-bar-height` | number > 0 | `28` | Menu-bar height |
 | `top-bar-margin-top` | integer ≥ 0 | `0` | Space above bar |
 | `top-bar-window-gap` | integer ≥ 0 | `0` | Clearance below bar |
diff --git a/shell/ferese-shell/src/desktop_widgets.rs b/shell/ferese-shell/src/desktop_widgets.rs
index 22779dc..f5aa76b 100644
--- a/shell/ferese-shell/src/desktop_widgets.rs
+++ b/shell/ferese-shell/src/desktop_widgets.rs
@@ -361,12 +361,13 @@ impl FereseShell {
             && editor.id == id
         {
             let id = id.to_owned();
+            let editor_radius = ferese_theme::inner_radius(self.config.theme.material_radius, note.padding);
             body = body.push(
                 cosmic::widget::TextEditor::new(&editor.content)
-                    .style(|theme, status| {
+                    .style(move |theme, status| {
                         use cosmic::iced::widget::text_editor::Catalog;
                         let mut style = theme.style(&<cosmic::Theme as Catalog>::default(), status);
-                        style.border.radius = motion::radius(f32::MAX).into();
+                        style.border.radius = editor_radius.into();
                         style
                     })
                     .height(Length::Fill)