diff --git a/data/Application.css b/data/Application.css
new file mode 100644
index 00000000..10ec098c
--- /dev/null
+++ b/data/Application.css
@@ -0,0 +1,4 @@
+entry.flat {
+    border: none;
+    box-shadow: none;
+}
diff --git a/data/io.elementary.calculator.gresource.xml b/data/io.elementary.calculator.gresource.xml
new file mode 100644
index 00000000..bb050eb3
--- /dev/null
+++ b/data/io.elementary.calculator.gresource.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<gresources>
+  <gresource prefix="/io/elementary/calculator">
+    <file compressed="true">Application.css</file>
+  </gresource>
+</gresources>
diff --git a/data/meson.build b/data/meson.build
index bf82962e..094a36b9 100644
--- a/data/meson.build
+++ b/data/meson.build
@@ -35,3 +35,8 @@ i18n.merge_file(
     install: true,
     install_dir: get_option('datadir') / 'metainfo',
 )
+
+css_gresource = gnome.compile_resources(
+    'gresource_css',
+    'io.elementary.calculator.gresource.xml'
+)
diff --git a/src/MainWindow.vala b/src/MainWindow.vala
index b3d3bb5f..eb888e58 100644
--- a/src/MainWindow.vala
+++ b/src/MainWindow.vala
@@ -118,6 +118,7 @@ public class PantheonCalculator.MainWindow : Gtk.ApplicationWindow {
             valign = Gtk.Align.FILL
         };
         entry.add_css_class (Granite.STYLE_CLASS_H2_LABEL);
+        entry.add_css_class (Granite.STYLE_CLASS_FLAT);
 
         button_calc = new Button ("=") {
             tooltip_text = _("Calculate Result")
diff --git a/src/meson.build b/src/meson.build
index 0207fbaa..a174e7b2 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -8,6 +8,7 @@ executable(
     'Core/Token.vala',
     'Core/Scanner.vala',
     'Core/Evaluation.vala',
+    css_gresource,
     dependencies: [
         core_deps,
         dependency('gtk4'),