Improve styling.

src/main.zig

@@ -7,11 +7,10 @@
 
 const std = @import("std");
 const adw = @import("adw");
-const gdk = @import("gdk");
 const gio = @import("gio");
-const gtk = @import("gtk");
 
 const Window = @import("Window.zig");
+const appearance = @import("appearance.zig");
 
 /// libghostty-vt logs unimplemented sequences at debug level, which is very
 /// chatty against a real shell. Keep the app's own warnings and errors.
@@ -19,8 +18,6 @@ pub const std_options: std.Options = .{
     .log_level = .info,
 };
 
-const css = @embedFile("style.css");
-
 var gpa: std.heap.DebugAllocator(.{}) = .init;
 
 pub fn main() u8 {
@@ -40,8 +37,9 @@ pub fn main() u8 {
 }
 
 fn onActivate(app: *adw.Application, _: ?*anyopaque) callconv(.c) void {
-    forceDark();
-    loadCss();
+    // Before the window, so that the first frame is drawn in the scheme the
+    // user chose rather than repainted into it a moment later.
+    appearance.init();
 
     const window = Window.create(gpa.allocator(), app) catch |err| {
         std.log.err("failed to create window: {s}", .{@errorName(err)});
@@ -49,25 +47,3 @@ fn onActivate(app: *adw.Application, _: ?*anyopaque) callconv(.c) void {
     };
     window.present();
 }
-
-/// The window's own chrome is dark by hand in `style.css`, but stock widgets —
-/// popovers, dialogs, text entries — follow the desktop's colour scheme and
-/// would come up light against it. Layouts brought the first real dialogs into
-/// the app, which is where that mismatch became visible.
-fn forceDark() void {
-    const manager = adw.StyleManager.getDefault();
-    manager.setColorScheme(.force_dark);
-}
-
-fn loadCss() void {
-    const display = gdk.Display.getDefault() orelse return;
-    const provider = gtk.CssProvider.new();
-    defer provider.unref();
-
-    provider.loadFromString(css);
-    gtk.StyleContext.addProviderForDisplay(
-        display,
-        provider.as(gtk.StyleProvider),
-        gtk.STYLE_PROVIDER_PRIORITY_APPLICATION,
-    );
-}