Dark theme (default): Fusion-like blue-grey viewport #2e3440, darker chrome, subtle grid, light text, blue accent; light theme kept as a second Tokens set; toggle on the application bar (sun/moon), ui.set {dark}, kept between runs (eframe storage; browser local storage on the web); viewport, sketch, glyph, view cube, timeline and overlay colours all come from the theme; preview spinner and state in ui.inspect

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AS5Tn3xieewUSg3uxrMVdL

crates/ui-egui/src/dialogs.rs

@@ -702,6 +702,9 @@ pub fn show(app: &mut SolveApp, ctx: &egui::Context) {
                 if ui.add(egui::Button::new(close).min_size(vec2(70.0, 24.0))).clicked() {
                     cancel = true;
                 }
+                if app.preview.busy {
+                    ui.add(egui::Spinner::new().size(14.0)).on_hover_text("Updating the preview");
+                }
             });
         });
     // Keyboard: Enter applies (from a value field, or with nothing focused), Esc cancels.