diff --git a/android/app/src/main/java/io/narl/protonstream/ui/theme/Shape.kt b/android/app/src/main/java/io/narl/protonstream/ui/theme/Shape.kt
index d204391..844af98 100644
--- a/android/app/src/main/java/io/narl/protonstream/ui/theme/Shape.kt
+++ b/android/app/src/main/java/io/narl/protonstream/ui/theme/Shape.kt
@@ -29,7 +29,7 @@ internal val ProtonShapes = Shapes(
 /** The radius `pstr-app` draws everything at. */
 internal const val CORNER = 8f
 
-/** A badge over artwork — `ui/mod.rs` is the other place this number lives. */
+/** A badge over artwork — `theme::radius::BADGE` in pstr-app is the other place this number lives. */
 internal const val CORNER_TIGHT = 4f
 
 /** A bottom sheet, which has no desktop counterpart. */
diff --git a/crates/pstr-app/src/app.rs b/crates/pstr-app/src/app.rs
index 2dc7fb1..4af1652 100644
--- a/crates/pstr-app/src/app.rs
+++ b/crates/pstr-app/src/app.rs
@@ -1432,14 +1432,14 @@ impl App {
         focus_search: bool,
     ) {
         ui.horizontal(|ui| {
-            ui.add_space(4.0);
+            ui.add_space(theme::space::XS);
             ui.label(
                 theme::Role::Heading
                     .rich("proton-stream")
                     .strong()
                     .color(theme::accent()),
             );
-            ui.add_space(12.0);
+            ui.add_space(theme::space::L);
 
             let on_library = matches!(self.page, Page::Library | Page::Title(_));
             let active = self
@@ -1475,7 +1475,7 @@ impl App {
             }
 
             ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
-                ui.add_space(4.0);
+                ui.add_space(theme::space::XS);
                 if self.crawling {
                     if ui
                         .small_button("Stop")
@@ -1504,7 +1504,7 @@ impl App {
                 }
 
                 if on_library && !self.library.is_empty() {
-                    ui.add_space(8.0);
+                    ui.add_space(theme::space::M);
                     ui::search_field(ui, search, focus_search);
                 }
             });
@@ -1914,7 +1914,7 @@ fn screenshot_name(title: &str, caption: &str, position: f64) -> String {
 /// rather than in one: the cut between two pages of tiles reads as a flicker,
 /// a short fade as a change of place.
 fn page_fade(ctx: &egui::Context, shown: &mut (Option<Page>, f64), page: &Page) -> f32 {
-    const SECONDS: f64 = 0.14;
+    const SECONDS: f64 = theme::motion::STATE as f64;
     let now = ctx.input(|input| input.time);
     if shown.0.as_ref() != Some(page) {
         // The first page of a launch is there at once; only changes fade.
@@ -1925,7 +1925,7 @@ fn page_fade(ctx: &egui::Context, shown: &mut (Option<Page>, f64), page: &Page)
     if progress < 1.0 {
         ctx.request_repaint();
     }
-    1.0 - (1.0 - progress).powi(3)
+    theme::motion::ease_out(progress)
 }
 
 /// What the top bar says while shares are being listed: one share by name,
diff --git a/crates/pstr-app/src/theme.rs b/crates/pstr-app/src/theme.rs
index 8e099a6..4813f82 100644
--- a/crates/pstr-app/src/theme.rs
+++ b/crates/pstr-app/src/theme.rs
@@ -107,6 +107,59 @@ impl Role {
     }
 }
 
+/// The spacing scale. Gaps between things come from here rather than being
+/// picked per call site, so two neighbouring groups are 12 apart or 16 apart
+/// and never 14 in one place and 15 in the next.
+pub mod space {
+    /// Between lines that belong to one thing: a title and its caption.
+    pub const XXS: f32 = 2.0;
+    pub const XS: f32 = 4.0;
+    /// Between controls in one cluster.
+    pub const S: f32 = 6.0;
+    pub const M: f32 = 8.0;
+    /// Between clusters on one row, and between rows of a form.
+    pub const L: f32 = 12.0;
+    /// Between the groups on a page.
+    pub const XL: f32 = 16.0;
+    /// Between sections.
+    pub const XXL: f32 = 24.0;
+}
+
+/// Corner radii, as `egui::CornerRadius::same` takes them.
+pub mod radius {
+    /// A progress bar, or a strip along an edge.
+    pub const BAR: u8 = 3;
+    /// A badge over artwork. Android's `Shape.kt` has the same number.
+    pub const BADGE: u8 = 4;
+    /// A small control inside something else: a menu entry, a chip.
+    pub const SM: u8 = 6;
+    /// Everything else either client paints: cards, buttons, the tab pill.
+    pub const MD: u8 = 8;
+    /// Something that floats: a row card, a dialog, a toast, the hero.
+    pub const LG: u8 = 12;
+}
+
+/// How long things take to change, in seconds, for `Context::animate_*`.
+pub mod motion {
+    /// A press, which has to answer before the finger is off the button.
+    pub const PRESS: f32 = 0.05;
+    /// A hover arriving and leaving.
+    pub const HOVER: f32 = 0.12;
+    /// A control changing state: a switch flipping, the tab pill travelling,
+    /// one page giving way to the next.
+    pub const STATE: f32 = 0.15;
+    /// Chrome fading in and out: the player's controls, a toast.
+    pub const FADE: f32 = 0.18;
+    /// Artwork arriving over its placeholder. Slower, because it replaces
+    /// something rather than adding to it, and a fast swap reads as a flicker.
+    pub const ARRIVE: f32 = 0.24;
+
+    /// Fast out, slow in: the curve every hand-driven transition uses.
+    pub fn ease_out(t: f32) -> f32 {
+        1.0 - (1.0 - t.clamp(0.0, 1.0)).powi(3)
+    }
+}
+
 /// The UI typeface, bundled rather than taken from the system so a title
 /// sets the same on every desktop. Inter, under the OFL — the licence is
 /// beside the files.
@@ -626,7 +679,7 @@ pub fn apply(ctx: &egui::Context, appearance: Appearance) {
     visuals.selection.stroke = Stroke::new(1.0, palette.text);
     visuals.hyperlink_color = palette.accent;
 
-    let radius = CornerRadius::same(8);
+    let radius = CornerRadius::same(radius::MD);
     visuals.widgets.noninteractive.bg_fill = palette.surface;
     visuals.widgets.noninteractive.corner_radius = radius;
     visuals.widgets.noninteractive.bg_stroke = Stroke::new(1.0, palette.border);
diff --git a/crates/pstr-app/src/ui/downloads.rs b/crates/pstr-app/src/ui/downloads.rs
index 4f444de..6053317 100644
--- a/crates/pstr-app/src/ui/downloads.rs
+++ b/crates/pstr-app/src/ui/downloads.rs
@@ -20,7 +20,7 @@ pub fn show(ui: &mut egui::Ui, downloads: &[DownloadItem], actions: &mut Vec<Act
         .show(ui, |ui| {
             ui.set_max_width(960.0);
             summary(ui, downloads);
-            ui.add_space(12.0);
+            ui.add_space(theme::space::L);
 
             let mut start = 0;
             while start < downloads.len() {
@@ -30,7 +30,7 @@ pub fn show(ui: &mut egui::Ui, downloads: &[DownloadItem], actions: &mut Vec<Act
                     .position(|item| item.target.title_key != *title_key)
                     .map_or(downloads.len(), |offset| start + offset);
                 group(ui, &downloads[start..end], actions);
-                ui.add_space(14.0);
+                ui.add_space(theme::space::L);
                 start = end;
             }
         });
@@ -108,7 +108,7 @@ fn group(ui: &mut egui::Ui, group: &[DownloadItem], actions: &mut Vec<Action>) {
     if totals_known && group.len() > 1 {
         ui::progress_bar(ui, fraction(downloaded, total), ui.available_width());
     }
-    ui.add_space(6.0);
+    ui.add_space(theme::space::S);
     for item in group {
         row(ui, item, actions);
     }
@@ -117,7 +117,7 @@ fn group(ui: &mut egui::Ui, group: &[DownloadItem], actions: &mut Vec<Action>) {
 fn row(ui: &mut egui::Ui, item: &DownloadItem, actions: &mut Vec<Action>) {
     egui::Frame::new()
         .fill(theme::card())
-        .corner_radius(egui::CornerRadius::same(6))
+        .corner_radius(egui::CornerRadius::same(theme::radius::SM))
         .inner_margin(egui::Margin::symmetric(12, 8))
         .show(ui, |ui| {
             ui.set_width(ui.available_width());
@@ -142,7 +142,7 @@ fn row(ui: &mut egui::Ui, item: &DownloadItem, actions: &mut Vec<Action>) {
                 ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
                     buttons(ui, item, actions);
                     if item.total > 0 && item.state != DownloadState::Completed {
-                        ui.add_space(8.0);
+                        ui.add_space(theme::space::M);
                         ui.label(ui::muted(format!(
                             "{} / {}",
                             size(item.downloaded),
@@ -154,7 +154,7 @@ fn row(ui: &mut egui::Ui, item: &DownloadItem, actions: &mut Vec<Action>) {
                 });
             });
         });
-    ui.add_space(4.0);
+    ui.add_space(theme::space::XS);
 }
 
 /// What a row says about itself, and in what colour.
diff --git a/crates/pstr-app/src/ui/library.rs b/crates/pstr-app/src/ui/library.rs
index 02ddc49..dcce0de 100644
--- a/crates/pstr-app/src/ui/library.rs
+++ b/crates/pstr-app/src/ui/library.rs
@@ -47,13 +47,13 @@ pub fn show(ui: &mut egui::Ui, art: &mut Art<'_>, shelves: Shelves<'_>, actions:
             if !searching {
                 if let Some(title) = featured(library, view, art.metadata, today()) {
                     hero(ui, art, title, actions);
-                    ui.add_space(18.0);
+                    ui.add_space(theme::space::XL);
                 }
                 let resumable = pick(&view.resumable);
                 if !resumable.is_empty() {
                     ui::section(ui, "Continue watching");
                     continue_row(ui, art, &resumable, actions);
-                    ui.add_space(16.0);
+                    ui.add_space(theme::space::XL);
                 }
             }
 
@@ -74,10 +74,10 @@ pub fn show(ui: &mut egui::Ui, art: &mut Art<'_>, shelves: Shelves<'_>, actions:
                     shelf_controls(ui, view, actions);
                 });
             });
-            ui.add_space(6.0);
+            ui.add_space(theme::space::S);
 
             if matches.is_empty() {
-                ui.add_space(8.0);
+                ui.add_space(theme::space::M);
                 ui.label(ui::muted(if searching {
                     "Nothing here by that name."
                 } else {
@@ -143,7 +143,7 @@ fn hero(ui: &mut egui::Ui, art: &mut Art<'_>, title: &Title, actions: &mut Vec<A
     if !ui.is_rect_visible(rect) {
         return;
     }
-    let radius = egui::CornerRadius::same(12);
+    let radius = egui::CornerRadius::same(theme::radius::LG);
     let picture = art.of(title);
     let found = art
         .metadata
@@ -152,9 +152,11 @@ fn hero(ui: &mut egui::Ui, art: &mut Art<'_>, title: &Title, actions: &mut Vec<A
 
     let painter = ui.painter().with_clip_rect(rect);
     painter.rect_filled(rect, radius, theme::card());
-    let art_in = ui
-        .ctx()
-        .animate_bool_with_time(response.id.with("art"), picture.is_some(), 0.3);
+    let art_in = ui.ctx().animate_bool_with_time(
+        response.id.with("art"),
+        picture.is_some(),
+        theme::motion::ARRIVE,
+    );
     if art_in < 1.0 {
         ui::placeholder(&painter, rect, "", 1.0 - art_in);
     }
@@ -220,13 +222,13 @@ fn hero(ui: &mut egui::Ui, art: &mut Art<'_>, title: &Title, actions: &mut Vec<A
                     if ui::accent_button(ui, &label).clicked() {
                         actions.push(Action::Play(PlaybackTarget::new(title, episode)));
                     }
-                    ui.add_space(6.0);
+                    ui.add_space(theme::space::S);
                 }
                 if ui.button("More info").clicked() {
                     actions.push(Action::Goto(Page::Title(title.key.clone())));
                 }
             });
-            ui.add_space(14.0);
+            ui.add_space(theme::space::L);
             if let Some(overview) = found.as_ref().and_then(|found| found.overview.as_deref()) {
                 let mut job = egui::text::LayoutJob::simple(
                     overview.to_owned(),
@@ -236,7 +238,7 @@ fn hero(ui: &mut egui::Ui, art: &mut Art<'_>, title: &Title, actions: &mut Vec<A
                 );
                 job.wrap.max_rows = 3;
                 ui.label(job);
-                ui.add_space(8.0);
+                ui.add_space(theme::space::M);
             }
             let mut facts = vec![subtitle(title)];
             if let Some(found) = &found {
@@ -246,7 +248,7 @@ fn hero(ui: &mut egui::Ui, art: &mut Art<'_>, title: &Title, actions: &mut Vec<A
                 facts.extend(found.genres.iter().take(3).cloned());
             }
             ui.label(ui::muted(facts.join("  ·  ")));
-            ui.add_space(2.0);
+            ui.add_space(theme::space::XXS);
             ui.add(
                 egui::Label::new(
                     theme::Role::Display
@@ -290,7 +292,7 @@ fn shelf_controls(ui: &mut egui::Ui, view: &LibraryView, actions: &mut Vec<Actio
     if let Some(Some(sort)) = sort.inner {
         actions.push(Action::SetShelf(view.filter, sort));
     }
-    ui.add_space(10.0);
+    ui.add_space(theme::space::L);
     if let Some(filter) = ui::widgets::segmented(
         ui,
         view.filter,
@@ -527,8 +529,11 @@ fn placeholder(ui: &mut egui::Ui) {
                     rect.min,
                     egui::vec2(grid.width, (grid.width * theme::CARD_ASPECT).round()),
                 );
-                ui.painter()
-                    .rect_filled(image, egui::CornerRadius::same(8), theme::card());
+                ui.painter().rect_filled(
+                    image,
+                    egui::CornerRadius::same(theme::radius::MD),
+                    theme::card(),
+                );
             }
         });
         ui.add_space(theme::CARD_GAP);
@@ -543,11 +548,11 @@ fn empty_state(ui: &mut egui::Ui, actions: &mut Vec<Action>) {
                 .rich("Nothing in the library yet")
                 .strong(),
         );
-        ui.add_space(6.0);
+        ui.add_space(theme::space::S);
         ui.label(ui::muted(
             "Add a Proton Drive share link, and everything playable behind it shows up here.",
         ));
-        ui.add_space(18.0);
+        ui.add_space(theme::space::XL);
         if ui::accent_button(ui, "Add a share").clicked() {
             actions.push(Action::Goto(Page::Shares));
         }
diff --git a/crates/pstr-app/src/ui/matcher.rs b/crates/pstr-app/src/ui/matcher.rs
index 00b3ec2..92592ec 100644
--- a/crates/pstr-app/src/ui/matcher.rs
+++ b/crates/pstr-app/src/ui/matcher.rs
@@ -43,7 +43,7 @@ pub fn show(
             egui::Frame::new()
                 .fill(theme::surface())
                 .inner_margin(egui::Margin::same(18))
-                .corner_radius(egui::CornerRadius::same(10)),
+                .corner_radius(egui::CornerRadius::same(theme::radius::LG)),
         )
         .show(ctx, |ui| {
             ui.set_width(620.0);
@@ -58,21 +58,21 @@ pub fn show(
                 "Everything {} answers with, in its own order — nothing is scored here.",
                 provider.label()
             )));
-            ui.add_space(10.0);
+            ui.add_space(theme::space::L);
 
             search_row(ui, matcher, actions);
-            ui.add_space(6.0);
+            ui.add_space(theme::space::S);
             current_row(ui, matcher, current.as_ref(), actions);
-            ui.add_space(10.0);
+            ui.add_space(theme::space::L);
 
             if let Some(error) = &matcher.error {
                 ui.label(theme::Role::Caption.rich(error).color(theme::danger()));
-                ui.add_space(6.0);
+                ui.add_space(theme::space::S);
             }
 
             results(ui, matcher, art, actions);
 
-            ui.add_space(12.0);
+            ui.add_space(theme::space::L);
             ui.horizontal(|ui| {
                 ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
                     if ui.button("Close").clicked() {
@@ -178,7 +178,7 @@ fn results(ui: &mut egui::Ui, matcher: &Matcher, art: &mut Art<'_>, actions: &mu
                 if row(ui, art, found).clicked() {
                     actions.push(Action::ChooseMatch(Box::new(found.clone())));
                 }
-                ui.add_space(4.0);
+                ui.add_space(theme::space::XS);
             }
         });
 }
@@ -188,7 +188,7 @@ fn results(ui: &mut egui::Ui, matcher: &Matcher, art: &mut Art<'_>, actions: &mu
 fn row(ui: &mut egui::Ui, art: &mut Art<'_>, found: &TitleMetadata) -> egui::Response {
     let response = egui::Frame::new()
         .fill(theme::card())
-        .corner_radius(egui::CornerRadius::same(6))
+        .corner_radius(egui::CornerRadius::same(theme::radius::SM))
         .inner_margin(egui::Margin::same(8))
         .show(ui, |ui| {
             ui.set_width(ui.available_width());
@@ -204,12 +204,12 @@ fn row(ui: &mut egui::Ui, art: &mut Art<'_>, found: &TitleMetadata) -> egui::Res
                 } else {
                     ui.painter().rect_filled(
                         rect,
-                        egui::CornerRadius::same(4),
+                        egui::CornerRadius::same(theme::radius::BADGE),
                         theme::card_hover(),
                     );
                 }
 
-                ui.add_space(10.0);
+                ui.add_space(theme::space::L);
                 ui.vertical(|ui| {
                     ui.label(
                         theme::Role::Body
@@ -241,7 +241,7 @@ fn row(ui: &mut egui::Ui, art: &mut Art<'_>, found: &TitleMetadata) -> egui::Res
     if response.hovered() {
         ui.painter().rect_stroke(
             response.rect,
-            egui::CornerRadius::same(6),
+            egui::CornerRadius::same(theme::radius::SM),
             egui::Stroke::new(1.5, theme::accent()),
             egui::StrokeKind::Inside,
         );
diff --git a/crates/pstr-app/src/ui/mod.rs b/crates/pstr-app/src/ui/mod.rs
index 169a199..23ebc75 100644
--- a/crates/pstr-app/src/ui/mod.rs
+++ b/crates/pstr-app/src/ui/mod.rs
@@ -141,14 +141,14 @@ pub fn format_size(bytes: i64) -> String {
 
 /// A section title with a rule under it.
 pub fn section(ui: &mut egui::Ui, text: &str) {
-    ui.add_space(6.0);
+    ui.add_space(theme::space::S);
     ui.label(
         theme::Role::Section
             .rich(text)
             .strong()
             .color(theme::text()),
     );
-    ui.add_space(2.0);
+    ui.add_space(theme::space::XXS);
 }
 
 /// Small grey text, for everything that is context rather than content.
@@ -173,7 +173,7 @@ pub fn search_field(ui: &mut egui::Ui, search: &mut String, focus: bool) {
     let has_focus = ui.memory(|memory| memory.has_focus(id));
     let lit = ui
         .ctx()
-        .animate_bool_with_time(id.with("lit"), has_focus, 0.12);
+        .animate_bool_with_time(id.with("lit"), has_focus, theme::motion::HOVER);
 
     let radius = CornerRadius::same((height / 2.0) as u8);
     ui.painter().rect_filled(outer, radius, theme::card());
@@ -258,7 +258,7 @@ pub fn search_field(ui: &mut egui::Ui, search: &mut String, focus: bool) {
 pub fn progress_bar(ui: &mut egui::Ui, fraction: f32, width: f32) -> egui::Response {
     let (rect, response) = ui.allocate_exact_size(Vec2::new(width, 6.0), Sense::hover());
     if ui.is_rect_visible(rect) {
-        let radius = CornerRadius::same(3);
+        let radius = CornerRadius::same(theme::radius::BAR);
         ui.painter().rect_filled(rect, radius, theme::card_hover());
         let mut done = rect;
         done.set_width(rect.width() * fraction.clamp(0.0, 1.0));
@@ -275,7 +275,7 @@ pub fn empty_state(ui: &mut egui::Ui, heading: &str, body: &str) {
     ui.vertical_centered(|ui| {
         ui.add_space(96.0);
         ui.label(theme::Role::Title.rich(heading).strong());
-        ui.add_space(6.0);
+        ui.add_space(theme::space::S);
         ui.label(muted(body));
     });
 }
@@ -311,7 +311,7 @@ pub fn confirm(ctx: &egui::Context, id: &str, heading: &str, body: &str, verb: &
             egui::Frame::new()
                 .fill(theme::surface())
                 .inner_margin(egui::Margin::same(18))
-                .corner_radius(CornerRadius::same(10)),
+                .corner_radius(CornerRadius::same(theme::radius::LG)),
         )
         .show(ctx, |ui| {
             ui.set_width(420.0);
@@ -321,9 +321,9 @@ pub fn confirm(ctx: &egui::Context, id: &str, heading: &str, body: &str, verb: &
                     .strong()
                     .color(theme::text()),
             );
-            ui.add_space(6.0);
+            ui.add_space(theme::space::S);
             ui.label(theme::Role::Body.rich(body).color(theme::muted()));
-            ui.add_space(16.0);
+            ui.add_space(theme::space::XL);
             ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
                 if danger_button(ui, verb).clicked() {
                     answer = Answer::Confirmed;
@@ -382,15 +382,17 @@ pub fn tabs(ui: &mut egui::Ui, id: egui::Id, items: &[(&str, bool)]) -> Option<u
         // the pill from overshooting when it moves between tabs of different
         // lengths — both edges arrive at the same time.
         let ctx = ui.ctx();
-        let left = ctx.animate_value_with_time(id.with("left"), target.left(), 0.16);
-        let right = ctx.animate_value_with_time(id.with("right"), target.right(), 0.16);
+        let left =
+            ctx.animate_value_with_time(id.with("left"), target.left(), theme::motion::STATE);
+        let right =
+            ctx.animate_value_with_time(id.with("right"), target.right(), theme::motion::STATE);
         let rect = Rect::from_min_max(
             egui::pos2(left, target.top()),
             egui::pos2(right, target.bottom()),
         );
         ui.painter().set(
             pill,
-            theme::accent_shape(ui.ctx(), rect, CornerRadius::same(8)),
+            theme::accent_shape(ui.ctx(), rect, CornerRadius::same(theme::radius::MD)),
         );
     }
 
@@ -431,17 +433,21 @@ fn filled(ui: &mut egui::Ui, text: &str, fill: Fill, extra: Vec2) -> egui::Respo
         return response;
     }
 
-    let radius = CornerRadius::same(8);
+    let radius = CornerRadius::same(theme::radius::MD);
     // Eased rather than switched, so the veil arrives over a few frames instead
     // of appearing whole the moment the pointer crosses the edge. The press is
     // quicker than the hover: a click should feel like it registered, not like
     // it was considered.
     let ctx = ui.ctx().clone();
-    let hover = ctx.animate_bool_with_time(response.id.with("hover"), response.hovered(), 0.10);
+    let hover = ctx.animate_bool_with_time(
+        response.id.with("hover"),
+        response.hovered(),
+        theme::motion::HOVER,
+    );
     let press = ctx.animate_bool_with_time(
         response.id.with("press"),
         response.is_pointer_button_down_on(),
-        0.05,
+        theme::motion::PRESS,
     );
     let lift = 0.10 * hover * (1.0 - press) - 0.14 * press;
 
@@ -510,7 +516,7 @@ pub fn card(ui: &mut egui::Ui, card: Card<'_>) -> egui::Response {
     let width = card.width;
     let image_height = (width * theme::CARD_ASPECT).round();
     let text_height = CARD_TEXT_HEIGHT;
-    let radius = CornerRadius::same(8);
+    let radius = CornerRadius::same(theme::radius::MD);
 
     let (rect, response) =
         ui.allocate_exact_size(Vec2::new(width, image_height + text_height), Sense::click());
@@ -533,14 +539,16 @@ pub fn card(ui: &mut egui::Ui, card: Card<'_>) -> egui::Response {
     let hover = ui.ctx().animate_bool_with_time(
         response.id.with("hover"),
         response.hovered() || response.has_focus(),
-        0.12,
+        theme::motion::HOVER,
     );
     // The picture arrives whenever its download finishes, several frames after
     // the tile first drew. Fading it in over the placeholder turns a wall of
     // letters popping into stills into one settle.
-    let art_in = ui
-        .ctx()
-        .animate_bool_with_time(response.id.with("art"), card.art.is_some(), 0.22);
+    let art_in = ui.ctx().animate_bool_with_time(
+        response.id.with("art"),
+        card.art.is_some(),
+        theme::motion::ARRIVE,
+    );
     let painter = ui.painter();
 
     if hover > 0.0 {
@@ -591,7 +599,7 @@ pub fn card(ui: &mut egui::Ui, card: Card<'_>) -> egui::Response {
         );
         painter.rect_filled(
             background,
-            CornerRadius::same(4),
+            CornerRadius::same(theme::radius::BADGE),
             Color32::from_black_alpha(180),
         );
         painter.galley(background.min + Vec2::new(5.0, 2.0), galley, Color32::WHITE);
@@ -724,7 +732,7 @@ pub(crate) fn placeholder(painter: &egui::Painter, rect: Rect, name: &str, opaci
     theme::ramp_fill(
         painter,
         rect,
-        CornerRadius::same(8),
+        CornerRadius::same(theme::radius::MD),
         (from, to),
         theme::Direction::Vertical,
         opacity,
diff --git a/crates/pstr-app/src/ui/player.rs b/crates/pstr-app/src/ui/player.rs
index f391843..4a8a2f6 100644
--- a/crates/pstr-app/src/ui/player.rs
+++ b/crates/pstr-app/src/ui/player.rs
@@ -251,7 +251,7 @@ pub fn show(
 
     // Faded rather than switched, both ways: controls that blink out under a
     // reading eye are more distracting than the ones that were there.
-    let fade = ctx.animate_bool_with_time(ui.id().with("chrome"), visible, 0.18);
+    let fade = ctx.animate_bool_with_time(ui.id().with("chrome"), visible, theme::motion::FADE);
     if fade > 0.0 {
         overlay.chrome_height = ui
             .scope(|ui| {
@@ -379,7 +379,7 @@ fn between(ui: &mut egui::Ui, opening: Option<&str>, rect: Rect, actions: &mut V
             if ui.button("Back").clicked() {
                 actions.push(Action::LeavePlayer);
             }
-            ui.add_space(8.0);
+            ui.add_space(theme::space::M);
             ui.add(egui::Spinner::new().size(14.0));
         },
     );
@@ -479,7 +479,7 @@ fn up_next_card(
         egui::Frame::new()
             .fill(Color32::from_black_alpha(215))
             .stroke(egui::Stroke::new(1.0, Color32::from_white_alpha(120)))
-            .corner_radius(CornerRadius::same(8))
+            .corner_radius(CornerRadius::same(theme::radius::MD))
             .inner_margin(egui::Margin::same(12))
             .show(ui, |ui| {
                 ui.set_width(size.x - 24.0);
@@ -488,7 +488,7 @@ fn up_next_card(
                     // coming and when, read in one glance.
                     let (frame, response) = ui.allocate_exact_size(STILL, Sense::click());
                     let painter = ui.painter();
-                    let radius = CornerRadius::same(6);
+                    let radius = CornerRadius::same(theme::radius::SM);
                     match &card.still {
                         Some(texture) => {
                             painter.add(
@@ -518,7 +518,7 @@ fn up_next_card(
                         actions.push(Action::PlayAdjacent(Adjacent::Next));
                     }
 
-                    ui.add_space(10.0);
+                    ui.add_space(theme::space::L);
                     ui.vertical(|ui| {
                         ui.label(
                             theme::Role::Caption
@@ -535,12 +535,12 @@ fn up_next_card(
                             )
                             .truncate(),
                         );
-                        ui.add_space(6.0);
+                        ui.add_space(theme::space::S);
                         ui.horizontal(|ui| {
                             if ui::accent_button(ui, "Play now").clicked() {
                                 actions.push(Action::PlayAdjacent(Adjacent::Next));
                             }
-                            ui.add_space(6.0);
+                            ui.add_space(theme::space::S);
                             if ui
                                 .button("Watch till the end")
                                 .on_hover_text("Play this one out — nothing will be skipped")
@@ -633,7 +633,7 @@ fn chrome(
                 .add(
                     egui::Button::new(theme::Role::Label.rich("Library"))
                         .fill(Color32::from_black_alpha(160))
-                        .corner_radius(CornerRadius::same(8))
+                        .corner_radius(CornerRadius::same(theme::radius::MD))
                         .min_size(Vec2::new(96.0, 32.0)),
                 )
                 .on_hover_text("Keep playing, and go back to the library (Esc)")
@@ -641,7 +641,7 @@ fn chrome(
             {
                 actions.push(Action::LeavePlayer);
             }
-            ui.add_space(14.0);
+            ui.add_space(theme::space::L);
             ui.vertical(|ui| {
                 ui.label(
                     theme::Role::Heading
@@ -666,7 +666,7 @@ fn chrome(
                             egui_phosphor::regular::CORNERS_OUT
                         }))
                         .fill(Color32::from_black_alpha(160))
-                        .corner_radius(CornerRadius::same(8))
+                        .corner_radius(CornerRadius::same(theme::radius::MD))
                         .min_size(Vec2::new(38.0, 32.0)),
                     )
                     .on_hover_text(if fullscreen {
diff --git a/crates/pstr-app/src/ui/settings.rs b/crates/pstr-app/src/ui/settings.rs
index ec144e3..b4f2a2a 100644
--- a/crates/pstr-app/src/ui/settings.rs
+++ b/crates/pstr-app/src/ui/settings.rs
@@ -50,7 +50,7 @@ pub fn show(
                 ui.add_space(margin);
                 ui.vertical(|ui| {
                     ui.set_width(width);
-                    ui.add_space(8.0);
+                    ui.add_space(theme::space::M);
                     appearance_form(ui, prefs.appearance, actions);
                     playback_form(ui, prefs, actions);
                     storage_form(ui, prefs, actions);
@@ -68,9 +68,9 @@ pub fn show(
 /// only changed a small square would be asking someone to imagine the result.
 fn appearance_form(ui: &mut egui::Ui, appearance: Appearance, actions: &mut Vec<Action>) {
     ui::widgets::settings_group(ui, "Appearance", None, |ui| {
-        ui.add_space(12.0);
+        ui.add_space(theme::space::L);
         ui.label(theme::Role::Body.rich("Palette").color(theme::text()));
-        ui.add_space(8.0);
+        ui.add_space(theme::space::M);
         ui.spacing_mut().item_spacing = egui::vec2(10.0, 10.0);
         ui.horizontal_wrapped(|ui| {
             for flavor in Flavor::ALL {
@@ -86,7 +86,7 @@ fn appearance_form(ui: &mut egui::Ui, appearance: Appearance, actions: &mut Vec<
                 }
             }
         });
-        ui.add_space(14.0);
+        ui.add_space(theme::space::L);
         ui.spacing_mut().item_spacing.y = 0.0;
 
         ui::widgets::settings_row(ui, "Accent", None, |ui| {
@@ -132,11 +132,11 @@ fn palette_card(ui: &mut egui::Ui, appearance: Appearance, flavor: Flavor) -> eg
             ..appearance
         });
         let selected = appearance.flavor == flavor;
-        let hover = ui
-            .ctx()
-            .animate_bool_with_time(response.id, response.hovered(), 0.10);
+        let hover =
+            ui.ctx()
+                .animate_bool_with_time(response.id, response.hovered(), theme::motion::HOVER);
         let painter = ui.painter();
-        let radius = egui::CornerRadius::same(8);
+        let radius = egui::CornerRadius::same(theme::radius::MD);
         let preview = egui::Rect::from_min_size(rect.min, egui::vec2(size.x, 64.0));
 
         painter.rect_filled(preview, radius, palette.background);
@@ -155,11 +155,20 @@ fn palette_card(ui: &mut egui::Ui, appearance: Appearance, flavor: Flavor) -> eg
             egui::Rect::from_min_size(preview.min + egui::vec2(x, 20.0), egui::vec2(34.0, 22.0))
         };
         for x in [8.0, 49.0, 90.0] {
-            painter.rect_filled(tile(x), egui::CornerRadius::same(3), palette.card);
+            painter.rect_filled(
+                tile(x),
+                egui::CornerRadius::same(theme::radius::BAR),
+                palette.card,
+            );
         }
         let pill =
             egui::Rect::from_min_size(preview.min + egui::vec2(8.0, 3.0), egui::vec2(22.0, 6.0));
-        theme::swatch_fill(painter, pill, egui::CornerRadius::same(3), &palette);
+        theme::swatch_fill(
+            painter,
+            pill,
+            egui::CornerRadius::same(theme::radius::BAR),
+            &palette,
+        );
         painter.hline(
             (preview.left() + 8.0)..=(preview.left() + 60.0),
             preview.top() + 50.0,
@@ -354,7 +363,7 @@ fn metadata_form(
     actions: &mut Vec<Action>,
 ) {
     ui::widgets::settings_group(ui, "Posters and descriptions", None, |ui| {
-        ui.add_space(12.0);
+        ui.add_space(theme::space::L);
         ui.spacing_mut().item_spacing.y = 6.0;
         ui.label(ui::muted(
             "A share filled by the Proton Drive desktop client carries no thumbnails, so \
@@ -362,7 +371,7 @@ fn metadata_form(
                  in your library — not your files, and nothing about what you have watched — to \
                  the provider you choose, over HTTPS, each time a new one appears.",
         ));
-        ui.add_space(10.0);
+        ui.add_space(theme::space::L);
 
         let mut changed = false;
         let mut enabled = settings.enabled;
@@ -372,7 +381,7 @@ fn metadata_form(
         }
 
         if settings.enabled {
-            ui.add_space(10.0);
+            ui.add_space(theme::space::L);
             ui.label(ui::muted("Provider"));
             for provider in ProviderId::ALL {
                 if ui
@@ -387,7 +396,7 @@ fn metadata_form(
             }
 
             if settings.provider.needs_api_key() {
-                ui.add_space(10.0);
+                ui.add_space(theme::space::L);
                 ui.label(ui::muted(format!("{} API key", settings.provider.label())));
                 ui.horizontal(|ui| {
                     ui.add(
@@ -409,7 +418,7 @@ fn metadata_form(
                 ));
             }
 
-            ui.add_space(12.0);
+            ui.add_space(theme::space::L);
             ui.horizontal(|ui| {
                 if ui::accent_button(ui, "Match the library").clicked() {
                     actions.push(Action::MatchTitles { force: false });
@@ -423,7 +432,7 @@ fn metadata_form(
                 }
             });
         } else {
-            ui.add_space(6.0);
+            ui.add_space(theme::space::S);
             ui.label(ui::muted(
                 "Off. Nothing is sent anywhere, and turning it off also deletes the answers \
                      already stored.",
@@ -433,6 +442,6 @@ fn metadata_form(
         if changed {
             actions.push(Action::SetMetadataConfig(settings.clone()));
         }
-        ui.add_space(12.0);
+        ui.add_space(theme::space::L);
     });
 }
diff --git a/crates/pstr-app/src/ui/shares.rs b/crates/pstr-app/src/ui/shares.rs
index 6891758..1bb3ce8 100644
--- a/crates/pstr-app/src/ui/shares.rs
+++ b/crates/pstr-app/src/ui/shares.rs
@@ -38,7 +38,7 @@ pub fn show(
                 share_row(ui, share, titles, actions);
             }
 
-            ui.add_space(22.0);
+            ui.add_space(theme::space::XXL);
             add_form(ui, shares, form, actions);
         });
 }
@@ -46,7 +46,7 @@ pub fn show(
 fn share_row(ui: &mut egui::Ui, share: &Share, titles: usize, actions: &mut Vec<Action>) {
     egui::Frame::new()
         .fill(theme::card())
-        .corner_radius(egui::CornerRadius::same(8))
+        .corner_radius(egui::CornerRadius::same(theme::radius::MD))
         .inner_margin(egui::Margin::symmetric(12, 10))
         .show(ui, |ui| {
             ui.set_width(ui.available_width());
@@ -76,7 +76,7 @@ fn share_row(ui: &mut egui::Ui, share: &Share, titles: usize, actions: &mut Vec<
                 });
             });
         });
-    ui.add_space(6.0);
+    ui.add_space(theme::space::S);
 }
 
 fn add_form(ui: &mut egui::Ui, shares: &[Share], form: &mut ShareForm, actions: &mut Vec<Action>) {
@@ -85,11 +85,11 @@ fn add_form(ui: &mut egui::Ui, shares: &[Share], form: &mut ShareForm, actions:
         "Paste the whole link, including everything after the # — that part is the key that \
          decrypts it, and it is stored in your system keyring rather than on disk.",
     ));
-    ui.add_space(10.0);
+    ui.add_space(theme::space::L);
 
     egui::Frame::new()
         .fill(theme::card())
-        .corner_radius(egui::CornerRadius::same(8))
+        .corner_radius(egui::CornerRadius::same(theme::radius::MD))
         .inner_margin(egui::Margin::same(14))
         .show(ui, |ui| {
             ui.set_width(ui.available_width().min(640.0));
@@ -100,7 +100,7 @@ fn add_form(ui: &mut egui::Ui, shares: &[Share], form: &mut ShareForm, actions:
                     .hint_text("Anime")
                     .desired_width(f32::INFINITY),
             );
-            ui.add_space(8.0);
+            ui.add_space(theme::space::M);
 
             ui.label(ui::muted("Link"));
             ui.horizontal(|ui| {
@@ -134,11 +134,11 @@ fn add_form(ui: &mut egui::Ui, shares: &[Share], form: &mut ShareForm, actions:
             if let Some(problem) = &problem {
                 ui.label(theme::Role::Caption.rich(problem).color(theme::danger()));
             }
-            ui.add_space(8.0);
+            ui.add_space(theme::space::M);
 
             ui::widgets::toggle(ui, &mut form.has_password, "The link asks for a password");
             if form.has_password {
-                ui.add_space(6.0);
+                ui.add_space(theme::space::S);
                 ui.add(
                     egui::TextEdit::singleline(&mut form.password)
                         .password(true)
@@ -147,7 +147,7 @@ fn add_form(ui: &mut egui::Ui, shares: &[Share], form: &mut ShareForm, actions:
                 );
             }
 
-            ui.add_space(12.0);
+            ui.add_space(theme::space::L);
             let ready = !form.name.trim().is_empty()
                 && !form.url.trim().is_empty()
                 && problem.is_none()
@@ -156,7 +156,7 @@ fn add_form(ui: &mut egui::Ui, shares: &[Share], form: &mut ShareForm, actions:
 
             if let Some(error) = &form.error {
                 ui.label(theme::Role::Caption.rich(error).color(theme::danger()));
-                ui.add_space(6.0);
+                ui.add_space(theme::space::S);
             }
             ui.horizontal(|ui| {
                 if ui
diff --git a/crates/pstr-app/src/ui/shortcuts.rs b/crates/pstr-app/src/ui/shortcuts.rs
index e935b6a..407630a 100644
--- a/crates/pstr-app/src/ui/shortcuts.rs
+++ b/crates/pstr-app/src/ui/shortcuts.rs
@@ -47,7 +47,7 @@ pub fn show(ctx: &egui::Context) -> bool {
             egui::Frame::new()
                 .fill(theme::surface())
                 .inner_margin(egui::Margin::same(20))
-                .corner_radius(egui::CornerRadius::same(12)),
+                .corner_radius(egui::CornerRadius::same(theme::radius::LG)),
         )
         .show(ctx, |ui| {
             ui.set_width(460.0);
@@ -60,9 +60,9 @@ pub fn show(ctx: &egui::Context) -> bool {
                 });
             });
             for (heading, keys) in GROUPS {
-                ui.add_space(12.0);
+                ui.add_space(theme::space::L);
                 ui.label(ui::muted(heading.to_uppercase()));
-                ui.add_space(4.0);
+                ui.add_space(theme::space::XS);
                 egui::Grid::new(*heading)
                     .num_columns(2)
                     .spacing([18.0, 8.0])
diff --git a/crates/pstr-app/src/ui/title.rs b/crates/pstr-app/src/ui/title.rs
index 208adf5..b5e4025 100644
--- a/crates/pstr-app/src/ui/title.rs
+++ b/crates/pstr-app/src/ui/title.rs
@@ -33,13 +33,13 @@ pub fn show(
     if back_link(ui).clicked() {
         actions.push(Action::Goto(Page::Library));
     }
-    ui.add_space(6.0);
+    ui.add_space(theme::space::S);
 
     egui::ScrollArea::vertical()
         .auto_shrink([false, false])
         .show(ui, |ui| {
             header(ui, art, title, &offline, actions);
-            ui.add_space(18.0);
+            ui.add_space(theme::space::XL);
 
             // One season at a time, picked from a row of pills, rather than
             // every season stacked as a collapsing header: a four-season show
@@ -78,7 +78,7 @@ pub fn show(
                         picked = index;
                         ui.data_mut(|data| data.insert_temp(picked_id, index));
                     }
-                    ui.add_space(10.0);
+                    ui.add_space(theme::space::L);
                 }
                 ui.label(ui::muted(ui::library::plural(
                     season.episodes.len(),
@@ -88,7 +88,7 @@ pub fn show(
                     season_download(ui, title, season, &offline, actions);
                 });
             });
-            ui.add_space(10.0);
+            ui.add_space(theme::space::L);
 
             let Some(season) = title.seasons.get(picked) else {
                 return;
@@ -96,7 +96,7 @@ pub fn show(
             for episode in &season.episodes {
                 episode_row(ui, art, title, season, episode, &offline, actions);
             }
-            ui.add_space(12.0);
+            ui.add_space(theme::space::L);
         });
 }
 
@@ -105,7 +105,7 @@ pub fn show(
 fn poster(ui: &mut egui::Ui, texture: &egui::TextureHandle, progress: Option<f64>) {
     let size = egui::vec2(180.0, 270.0);
     let (rect, _) = ui.allocate_exact_size(size, egui::Sense::hover());
-    let radius = egui::CornerRadius::same(10);
+    let radius = egui::CornerRadius::same(theme::radius::LG);
     ui.painter()
         .add(theme::tile_shadow(1.0).as_shape(rect, radius));
     ui.painter().add(
@@ -201,7 +201,7 @@ fn header(
         .as_ref()
         .map(|(texture, _)| (texture.clone(), ui.painter().add(egui::Shape::Noop)));
 
-    ui.add_space(6.0);
+    ui.add_space(theme::space::S);
     ui.horizontal_top(|ui| {
         match &picture {
             // A poster is drawn as a poster. Fitted into the 16:9 tile the grid
@@ -224,7 +224,7 @@ fn header(
             }
         }
 
-        ui.add_space(22.0);
+        ui.add_space(theme::space::XXL);
         ui.vertical(|ui| {
             // Text in a column a person can read, with the picture to the
             // right of it rather than under it.
@@ -242,9 +242,9 @@ fn header(
                     if by_hand { " (chosen by hand)" } else { "" }
                 )));
             }
-            ui.add_space(4.0);
+            ui.add_space(theme::space::XS);
             ui.label(ui::muted(meta_line(title, found.as_ref())));
-            ui.add_space(14.0);
+            ui.add_space(theme::space::L);
 
             ui.horizontal(|ui| {
                 if let Some(episode) = title.next_up() {
@@ -342,14 +342,14 @@ fn header(
             });
 
             if let Some(found) = &found {
-                ui.add_space(14.0);
+                ui.add_space(theme::space::L);
                 description(ui, found);
             }
         });
     });
 
     if let Some((texture, index)) = backdrop {
-        ui.add_space(10.0);
+        ui.add_space(theme::space::L);
         band(ui, &texture, index);
     }
 }
@@ -456,7 +456,7 @@ fn description(ui: &mut egui::Ui, found: &TitleMetadata) {
                 ui::widgets::chip(ui, genre);
             }
         });
-        ui.add_space(8.0);
+        ui.add_space(theme::space::M);
     }
     if let Some(overview) = &found.overview {
         // Four lines, then "More". A provider's synopsis runs to three
@@ -496,7 +496,7 @@ fn description(ui: &mut egui::Ui, found: &TitleMetadata) {
         }
     }
     if let Some(url) = &found.url {
-        ui.add_space(8.0);
+        ui.add_space(theme::space::M);
         ui.hyperlink_to(
             ui::muted(format!("More on {}", found.provider.label())),
             url,
@@ -573,7 +573,7 @@ fn episode_row(
     let row_id = ui.id().with(("episode", &episode.node.link_id));
 
     let frame = egui::Frame::new()
-        .corner_radius(egui::CornerRadius::same(10))
+        .corner_radius(egui::CornerRadius::same(theme::radius::LG))
         .inner_margin(egui::Margin::same(8));
     let mut prepared = frame.begin(ui);
     {
@@ -581,7 +581,7 @@ fn episode_row(
         ui.set_width(ui.available_width());
         ui.horizontal_top(|ui| {
             still(ui, art, title, episode, watched, actions);
-            ui.add_space(6.0);
+            ui.add_space(theme::space::S);
 
             let controls = 96.0;
             let text_width = (ui.available_width() - controls).max(120.0);
@@ -665,7 +665,7 @@ fn episode_row(
                         duration: episode.watch.and_then(|watch| watch.duration_secs),
                     });
                 }
-                ui.add_space(6.0);
+                ui.add_space(theme::space::S);
                 download(ui, title, episode, offline, actions);
             });
         });
@@ -676,11 +676,11 @@ fn episode_row(
     let lit = ui.ctx().animate_bool_with_time(
         row_id,
         response.hovered() || response.contains_pointer(),
-        0.10,
+        theme::motion::HOVER,
     );
     prepared.frame.fill = theme::card().gamma_multiply(0.35 + 0.65 * lit);
     prepared.paint(ui);
-    ui.add_space(2.0);
+    ui.add_space(theme::space::XXS);
 }
 
 /// The grey line under an episode's name: when it aired, how big it is, and
@@ -728,7 +728,7 @@ fn still(
     if !ui.is_rect_visible(rect) {
         return;
     }
-    let radius = egui::CornerRadius::same(8);
+    let radius = egui::CornerRadius::same(theme::radius::MD);
     let painter = ui.painter();
     painter.rect_filled(rect, radius, theme::card_hover());
     // Asked for only once the row is on screen: a season of twenty-five is
@@ -751,7 +751,7 @@ fn still(
     let hover = ui.ctx().animate_bool_with_time(
         response.id,
         response.hovered() || response.has_focus(),
-        0.12,
+        theme::motion::HOVER,
     );
     if hover > 0.0 {
         painter.rect_filled(
diff --git a/crates/pstr-app/src/ui/toast.rs b/crates/pstr-app/src/ui/toast.rs
index 77b93d6..12dba8b 100644
--- a/crates/pstr-app/src/ui/toast.rs
+++ b/crates/pstr-app/src/ui/toast.rs
@@ -17,7 +17,7 @@ const ERROR_SECONDS: f64 = 9.0;
 /// How many fit at once. A burst beyond that drops the oldest.
 const MOST: usize = 4;
 /// How long one takes to arrive and to leave.
-const FADE: f64 = 0.18;
+const FADE: f64 = theme::motion::FADE as f64;
 const WIDTH: f32 = 340.0;
 
 pub struct Toast {
@@ -98,7 +98,7 @@ impl Toasts {
             let age = now - toast.at;
             let arriving = (age / FADE).clamp(0.0, 1.0) as f32;
             let leaving = ((life - age) / FADE).clamp(0.0, 1.0) as f32;
-            let opacity = ease(arriving.min(leaving));
+            let opacity = theme::motion::ease_out(arriving.min(leaving));
 
             let area = egui::Area::new(egui::Id::new(("toast", toast.id)))
                 .order(egui::Order::Foreground)
@@ -150,10 +150,6 @@ fn lifetime(error: bool) -> f64 {
     if error { ERROR_SECONDS } else { SECONDS }
 }
 
-fn ease(t: f32) -> f32 {
-    1.0 - (1.0 - t).powi(3)
-}
-
 /// Which of a toast's buttons was pressed.
 enum Pressed {
     Nothing,
@@ -172,7 +168,7 @@ fn card(ui: &mut egui::Ui, toast: &Toast) -> Pressed {
     egui::Frame::new()
         .fill(theme::surface())
         .stroke(Stroke::new(1.0, theme::card_hover()))
-        .corner_radius(CornerRadius::same(10))
+        .corner_radius(CornerRadius::same(theme::radius::LG))
         .inner_margin(egui::Margin {
             left: 16,
             right: 10,
@@ -211,7 +207,7 @@ fn card(ui: &mut egui::Ui, toast: &Toast) -> Pressed {
                     pressed = Pressed::Close;
                 }
                 if let Some((label, _)) = &toast.action {
-                    ui.add_space(4.0);
+                    ui.add_space(theme::space::XS);
                     if ui
                         .add(
                             egui::Button::new(
@@ -240,7 +236,8 @@ fn card(ui: &mut egui::Ui, toast: &Toast) -> Pressed {
                 egui::pos2(frame.left() - 10.0, frame.top() - 4.0),
                 egui::pos2(frame.left() - 7.0, frame.bottom() + 4.0),
             );
-            ui.painter().rect_filled(strip, CornerRadius::same(2), edge);
+            ui.painter()
+                .rect_filled(strip, CornerRadius::same(theme::radius::BAR), edge);
         });
     pressed
 }
diff --git a/crates/pstr-app/src/ui/transport.rs b/crates/pstr-app/src/ui/transport.rs
index 46a55ea..2060199 100644
--- a/crates/pstr-app/src/ui/transport.rs
+++ b/crates/pstr-app/src/ui/transport.rs
@@ -56,7 +56,7 @@ pub fn full(
 ) {
     seek_bar(ui, playback, actions, 6.0);
     times(ui, playback, true);
-    ui.add_space(6.0);
+    ui.add_space(theme::space::S);
 
     ui.horizontal(|ui| {
         ui.set_min_height(ROW_HEIGHT_FULL);
@@ -87,7 +87,7 @@ pub fn full(
             },
         );
 
-        ui.add_space(12.0);
+        ui.add_space(theme::space::L);
         if playback.seeking || playback.buffering || !playback.loaded {
             ui.add(egui::Spinner::new().size(16.0));
             ui.label(ui::muted(if playback.loaded && playback.seeking {
@@ -100,11 +100,11 @@ pub fn full(
         // Right cluster: everything that is a choice rather than a move.
         ui.with_layout(egui::Layout::right_to_left(egui::Align::Center), |ui| {
             track_menus(ui, playback, actions);
-            ui.add_space(8.0);
+            ui.add_space(theme::space::M);
             speed_menu(ui, playback, actions);
-            ui.add_space(8.0);
+            ui.add_space(theme::space::M);
             chapter_menu(ui, playback, actions);
-            ui.add_space(8.0);
+            ui.add_space(theme::space::M);
             volume(ui, playback, actions);
         });
     });
@@ -130,7 +130,7 @@ pub fn mini(
             Some(texture) => {
                 let (rect, response) = ui.allocate_exact_size(MINI_PICTURE, Sense::click());
                 let painter = ui.painter();
-                let radius = CornerRadius::same(6);
+                let radius = CornerRadius::same(theme::radius::SM);
                 painter.rect_filled(rect, radius, Color32::BLACK);
                 painter.add(
                     egui::epaint::RectShape::filled(rect, radius, Color32::WHITE).with_texture(
@@ -141,7 +141,7 @@ pub fn mini(
                 let hover = ui.ctx().animate_bool_with_time(
                     response.id.with("hover"),
                     response.hovered(),
-                    0.12,
+                    theme::motion::HOVER,
                 );
                 if hover > 0.0 {
                     painter.rect_filled(
@@ -172,7 +172,7 @@ pub fn mini(
                     .add(
                         egui::Button::new(theme::Role::Label.rich("Back to video"))
                             .fill(theme::card_hover())
-                            .corner_radius(CornerRadius::same(8)),
+                            .corner_radius(CornerRadius::same(theme::radius::MD)),
                     )
                     .on_hover_text("Show the picture again")
                     .clicked()
@@ -181,7 +181,7 @@ pub fn mini(
                 }
             }
         }
-        ui.add_space(10.0);
+        ui.add_space(theme::space::L);
         ui.vertical(|ui| {
             ui.horizontal(|ui| {
                 ui.set_min_height(ROW_HEIGHT_MINI);
@@ -208,7 +208,7 @@ pub fn mini(
                     if ui.button("Stop").clicked() {
                         actions.push(Action::Player(Command::Stop));
                     }
-                    ui.add_space(6.0);
+                    ui.add_space(theme::space::S);
                     step_button(
                         ui,
                         egui_phosphor::regular::SKIP_FORWARD,
@@ -231,18 +231,18 @@ pub fn mini(
                         },
                     );
 
-                    ui.add_space(8.0);
+                    ui.add_space(theme::space::M);
                     track_menus(ui, playback, actions);
-                    ui.add_space(6.0);
+                    ui.add_space(theme::space::S);
                     volume(ui, playback, actions);
 
                     if playback.seeking || playback.buffering || !playback.loaded {
-                        ui.add_space(6.0);
+                        ui.add_space(theme::space::S);
                         ui.add(egui::Spinner::new().size(14.0));
                     }
                 });
             });
-            ui.add_space(4.0);
+            ui.add_space(theme::space::XS);
             seek_bar(ui, playback, actions, 5.0);
             times(ui, playback, false);
         });
@@ -569,11 +569,11 @@ fn seek_bar(ui: &mut egui::Ui, playback: &Playback, actions: &mut Vec<Action>, t
 
     let active = response.hovered() || response.dragged();
     // Grows rather than jumps when the pointer arrives.
-    let grow = ui
-        .ctx()
-        .animate_bool_with_time(response.id.with("grow"), active, 0.12);
+    let grow =
+        ui.ctx()
+            .animate_bool_with_time(response.id.with("grow"), active, theme::motion::HOVER);
     let track = Rect::from_center_size(rect.center(), Vec2::new(width, thickness + 3.0 * grow));
-    let radius = CornerRadius::same(3);
+    let radius = CornerRadius::same(theme::radius::BAR);
     let painter = ui.painter();
     // From the palette rather than a fixed grey: the same bar sits on the
     // video's dark scrim and on a light theme's transport strip.
@@ -692,6 +692,10 @@ fn bubble(ui: &egui::Ui, anchor: egui::Pos2, text: &str) {
     let screen = ui.ctx().content_rect();
     let left = (anchor.x - size.x / 2.0).clamp(screen.left() + 4.0, screen.right() - size.x - 4.0);
     let frame = Rect::from_min_size(egui::pos2(left, anchor.y - size.y), size);
-    painter.rect_filled(frame, CornerRadius::same(6), Color32::from_black_alpha(215));
+    painter.rect_filled(
+        frame,
+        CornerRadius::same(theme::radius::SM),
+        Color32::from_black_alpha(215),
+    );
     painter.galley(frame.min + Vec2::new(8.0, 4.0), galley, Color32::WHITE);
 }
diff --git a/crates/pstr-app/src/ui/widgets.rs b/crates/pstr-app/src/ui/widgets.rs
index 993f060..eb0de65 100644
--- a/crates/pstr-app/src/ui/widgets.rs
+++ b/crates/pstr-app/src/ui/widgets.rs
@@ -40,8 +40,12 @@ pub fn toggle(ui: &mut egui::Ui, on: &mut bool, text: &str) -> egui::Response {
 
     if ui.is_rect_visible(rect) {
         let ctx = ui.ctx();
-        let t = ctx.animate_bool_with_time(response.id, *on, 0.14);
-        let hover = ctx.animate_bool_with_time(response.id.with("hover"), response.hovered(), 0.10);
+        let t = ctx.animate_bool_with_time(response.id, *on, theme::motion::STATE);
+        let hover = ctx.animate_bool_with_time(
+            response.id.with("hover"),
+            response.hovered(),
+            theme::motion::HOVER,
+        );
         let track = egui::Rect::from_min_size(
             egui::pos2(rect.left(), rect.center().y - TRACK.y / 2.0),
             TRACK,
@@ -96,8 +100,12 @@ pub fn watched_mark(ui: &mut egui::Ui, watched: bool) -> egui::Response {
     let (rect, response) = ui.allocate_exact_size(Vec2::splat(SIZE), Sense::click());
     if ui.is_rect_visible(rect) {
         let ctx = ui.ctx();
-        let t = ctx.animate_bool_with_time(response.id, watched, 0.14);
-        let hover = ctx.animate_bool_with_time(response.id.with("hover"), response.hovered(), 0.10);
+        let t = ctx.animate_bool_with_time(response.id, watched, theme::motion::STATE);
+        let hover = ctx.animate_bool_with_time(
+            response.id.with("hover"),
+            response.hovered(),
+            theme::motion::HOVER,
+        );
         let painter = ui.painter();
         let center = rect.center();
         let radius = SIZE / 2.0 - 1.0;
@@ -147,7 +155,7 @@ pub fn settings_group<R>(
     description: Option<&str>,
     add: impl FnOnce(&mut egui::Ui) -> R,
 ) -> R {
-    ui.add_space(4.0);
+    ui.add_space(theme::space::XS);
     ui.label(
         theme::Role::Subhead
             .rich(heading)
@@ -155,13 +163,13 @@ pub fn settings_group<R>(
             .color(theme::text()),
     );
     if let Some(description) = description {
-        ui.add_space(2.0);
+        ui.add_space(theme::space::XXS);
         ui.label(crate::ui::muted(description));
     }
-    ui.add_space(8.0);
+    ui.add_space(theme::space::M);
     let inner = egui::Frame::new()
         .fill(theme::card())
-        .corner_radius(CornerRadius::same(10))
+        .corner_radius(CornerRadius::same(theme::radius::LG))
         .inner_margin(egui::Margin::symmetric(16, 6))
         .show(ui, |ui| {
             ui.set_width(ui.available_width());
@@ -169,7 +177,7 @@ pub fn settings_group<R>(
             add(ui)
         })
         .inner;
-    ui.add_space(26.0);
+    ui.add_space(theme::space::XXL);
     inner
 }
 
@@ -192,7 +200,7 @@ pub fn settings_row<R>(
             Stroke::new(1.0, theme::card_hover()),
         );
     }
-    ui.add_space(10.0);
+    ui.add_space(theme::space::L);
     let inner = ui
         .horizontal(|ui| {
             ui.set_min_height(28.0);
@@ -209,7 +217,7 @@ pub fn settings_row<R>(
                 .inner
         })
         .inner;
-    ui.add_space(10.0);
+    ui.add_space(theme::space::L);
     inner
 }
 
@@ -224,7 +232,7 @@ pub fn segmented<T: Copy + PartialEq>(
     let mut picked = None;
     egui::Frame::new()
         .fill(theme::card_hover())
-        .corner_radius(CornerRadius::same(8))
+        .corner_radius(CornerRadius::same(theme::radius::MD))
         .inner_margin(egui::Margin::same(3))
         .show(ui, |ui| {
             ui.spacing_mut().item_spacing.x = 2.0;
@@ -237,7 +245,7 @@ pub fn segmented<T: Copy + PartialEq>(
                         theme::text()
                     });
                     let button = egui::Button::new(text)
-                        .corner_radius(CornerRadius::same(6))
+                        .corner_radius(CornerRadius::same(theme::radius::SM))
                         .fill(if selected {
                             theme::accent()
                         } else {
@@ -273,9 +281,9 @@ pub fn download_button(ui: &mut egui::Ui, glyph: DownloadGlyph) -> egui::Respons
     if !ui.is_rect_visible(rect) {
         return response;
     }
-    let hover = ui
-        .ctx()
-        .animate_bool_with_time(response.id, response.hovered(), 0.10);
+    let hover =
+        ui.ctx()
+            .animate_bool_with_time(response.id, response.hovered(), theme::motion::HOVER);
     let painter = ui.painter();
     let c = rect.center();
     if hover > 0.0 {
@@ -352,7 +360,7 @@ pub fn download_button(ui: &mut egui::Ui, glyph: DownloadGlyph) -> egui::Respons
 pub fn chip(ui: &mut egui::Ui, text: &str) -> egui::Response {
     egui::Frame::new()
         .fill(theme::card_hover().gamma_multiply(0.8))
-        .corner_radius(CornerRadius::same(10))
+        .corner_radius(CornerRadius::same(theme::radius::LG))
         .inner_margin(egui::Margin::symmetric(9, 3))
         .show(ui, |ui| {
             ui.label(theme::Role::Caption.rich(text).color(theme::text()));
diff --git a/docs/DESIGN-TOKENS.md b/docs/DESIGN-TOKENS.md
index 97443f7..3ad1167 100644
--- a/docs/DESIGN-TOKENS.md
+++ b/docs/DESIGN-TOKENS.md
@@ -12,10 +12,11 @@ is the contract, and each side's copy is asserted against it by a test.
 |---|---|---|---|
 | Colour roles | `pstr_core::appearance::Palette` | `ui/theme/Theme.kt` `schemeOf` | `SchemeRolesTest` |
 | Type ramp | `pstr_app::theme::Role` | `ui/theme/Type.kt` | `TypeRampTest` |
-| Corner radius | `pstr-app` `ui/mod.rs` | `ui/theme/Shape.kt` | `TypeRampTest` |
+| Corner radius | `pstr_app::theme::radius` | `ui/theme/Shape.kt` | `TypeRampTest` |
 | Gradient rule | `Palette::resolve` | — (derived, see below) | `appearance.rs` tests |
 | Depth | `pstr_app::theme::{tile_shadow, bar_shadow}` | Material elevation | — |
-| Motion | `Context::animate_*` | Compose defaults | — |
+| Spacing | `pstr_app::theme::space` | Compose `dp` literals | — |
+| Motion | `pstr_app::theme::motion` | Compose defaults | — |
 
 ## Type
 
@@ -54,9 +55,19 @@ this module, and keep Material's sizes. Nothing in the app draws with them.
 
 ## Shape
 
-**Radius 8** for everything either client paints: cards, buttons, the tab pill,
-progress bars, dialogs. **4** for a badge over artwork. **16** for an Android
-bottom sheet, which has no desktop counterpart.
+**Radius 8** (`radius::MD`) for everything either client paints: cards,
+buttons, the tab pill. **4** (`BADGE`) for a badge over artwork. The desktop
+also has **3** (`BAR`) for progress bars and edge strips, **6** (`SM`) for a
+small control inside something else, and **12** (`LG`) for what floats — row
+cards, dialogs, toasts, the hero. **16** for an Android bottom sheet, which has
+no desktop counterpart.
+
+## Spacing
+
+The desktop spaces things from one scale, `theme::space`: 2, 4, 6, 8, 12, 16,
+24 (`XXS` to `XXL`). Use a step of the scale for a gap, not a literal. Sizes of
+things — a still, a button, a column — are not spacing and stay where they are
+defined.
 
 Two traps, both Android's:
 
@@ -104,9 +115,11 @@ page is a smudge on a near-white one. Android gets Material's elevation, which
 already adapts. Neither uses a tint to say "raised".
 
 Transitions on the desktop go through `Context::animate_*`: wall-clock driven,
-frame-rate independent, no state held by the caller. Durations in use are 0.05 s
-for a press, 0.10–0.12 s for a hover, 0.16 s for the tab pill's travel and 0.22 s
-for artwork arriving. Compose's defaults are close enough that nothing here
+frame-rate independent, no state held by the caller. Durations come from
+`theme::motion`: `PRESS` 0.05 s, `HOVER` 0.12 s, `STATE` 0.15 s (a switch, the
+tab pill's travel, a page change), `FADE` 0.18 s (player chrome, toasts) and
+`ARRIVE` 0.24 s (artwork over its placeholder). A hand-driven transition eases
+with `motion::ease_out`. Compose's defaults are close enough that nothing here
 overrides them.
 
 ## Desktop widgets