From 441af8389b9227eb74fd75e89dd7f14ebce6a69c Mon Sep 17 00:00:00 2001
From: Mitchell Hashimoto <m@mitchellh.com>
Date: Sun, 10 Aug 2025 13:05:17 -0700
Subject: [PATCH] apprt/gtk-ng: split separator styling

---
 src/apprt/gtk-ng/css/style-dark.css          |  5 +++++
 src/apprt/gtk-ng/css/style.css               | 23 ++++++++++++++++++++
 src/apprt/gtk-ng/ui/1.5/split-tree-split.blp |  4 ++++
 3 files changed, 32 insertions(+)

diff --git a/src/apprt/gtk-ng/css/style-dark.css b/src/apprt/gtk-ng/css/style-dark.css
index a9aa2dcc0..f13b4f4f0 100644
--- a/src/apprt/gtk-ng/css/style-dark.css
+++ b/src/apprt/gtk-ng/css/style-dark.css
@@ -1,3 +1,8 @@
 .transparent {
   background-color: transparent;
 }
+
+.window .split paned > separator {
+  background-color: rgba(36, 36, 36, 1);
+  background-clip: content-box;
+}
diff --git a/src/apprt/gtk-ng/css/style.css b/src/apprt/gtk-ng/css/style.css
index 970c91b03..a1a425f66 100644
--- a/src/apprt/gtk-ng/css/style.css
+++ b/src/apprt/gtk-ng/css/style.css
@@ -114,3 +114,26 @@ label.resize-overlay {
   margin-left: 4px;
   margin-right: 8px;
 }
+
+/*
+ * Splits
+ */
+
+.window .split paned > separator {
+  background-color: rgba(250, 250, 250, 1);
+  background-clip: content-box;
+
+  /* This works around the oversized drag area for the right side of GtkPaned.
+   *
+   * Upstream Gtk issue:
+   * https://gitlab.gnome.org/GNOME/gtk/-/issues/4484#note_2362002
+   *
+   * Ghostty issue:
+   * https://github.com/ghostty-org/ghostty/issues/3020
+   *
+   * Without this, it's not possible to select the first character on the
+   * right-hand side of a split.
+   */
+  margin: 0;
+  padding: 0;
+}
diff --git a/src/apprt/gtk-ng/ui/1.5/split-tree-split.blp b/src/apprt/gtk-ng/ui/1.5/split-tree-split.blp
index aa194e8e8..182919f4e 100644
--- a/src/apprt/gtk-ng/ui/1.5/split-tree-split.blp
+++ b/src/apprt/gtk-ng/ui/1.5/split-tree-split.blp
@@ -2,6 +2,10 @@ using Gtk 4.0;
 using Adw 1;
 
 template $GhosttySplitTreeSplit: Adw.Bin {
+  styles [
+    "split",
+  ]
+
   // The double-nesting is required due to a GTK bug where you can't
   // bind the first child of a builder layout. If you do, you get a double
   // dispose. Easiest way to see that is simply remove this and see the