'border' as panel button border, add_from_file method

- Use 'border' as panel button border, not 'box-shadow';
- Added add_from_file method to ThemePreparation.

tweaks/overview/tweak.py

@@ -1,4 +1,6 @@
 from scripts import config
+from scripts.utils.theme.theme import Theme
+
 overview_folder = f"{config.tweaks_folder}/overview"
 
 
@@ -7,9 +9,7 @@ def define_arguments(parser):
     overview_args.add_argument('--launchpad', action='store_true', help='change Show Apps icon to macOS Launchpad icon')
 
 
-def apply_tweak(args, theme, colors):
+def apply_tweak(args, theme: Theme, colors):
     if args.launchpad:
-        with open(f"{overview_folder}/launchpad/launchpad.css", "r") as f:
-            theme += f.read()
-
+        theme.add_from_file(f"{overview_folder}/launchpad/launchpad.css")
         theme *= f"{overview_folder}/launchpad/launchpad.png"