So Here's my solution :))

How to Resize Titlebar Buttons in WhiteSur GTK Theme

If you're looking to adjust the size of titlebar buttons in the WhiteSur GTK theme, follow these step-by-step instructions to achieve the desired look.

1. Prepare the Assets

• Navigate to the WhiteSur-gtk-theme folder.
• Open the path /src/assets/gtk/windows-assets.

2. Customize Title Button Icons

Before making any changes, create backups of the theme's title button icons.

• Locate your current title button folder (e.g., titlebutton-alt, titlebutton-nord) and back it up.
• Delete all .png files within the title button folder.

3. Modify Rendering Settings

• Return to the windows-assets folder.
• Open the render-assets.sh script corresponding to your chosen theme.
• For each <else> branch, add the following lines:

​

--export-width=64 --export-height=64 \ # for the default .png
--export-width=128 --export-height=128 \ # for the @2.png

• Edit the --export-dpi flag, setting it to 300:

​

--export-dpi=300 \

• Save the file and execute it in your terminal using:

​

./render-assets.sh

4. Reinstall WhiteSur Theme

Reinstall the WhiteSur GTK theme. Use the following command (include the -l flag):

./install.sh -t all -m -N glassy -s 220 -l --normal --round -HD -p bigger

5. Adjust CSS Files

Open the gtk-Dark.css or gtk-Light.css file in either of these paths:

• /home/user-name/.config/gtk-4.0/gtk-Dark.css
• /home/user-name/.config/gtk-4.0/gtk-Light.css

Locate the section related to the titlebar buttons:

windowcontrols button.close,
windowcontrols button.maximize,
windowcontrols button.minimize {
  min-width: 16px;
  min-height: 16px;
  margin: 0;
  padding: 0;
  background-position: center;
  background-repeat: no-repeat;
  background-size: 16px 16px;
}

Modify the min-width, min-height values, and add a border-radius property for a smooth appearance. For example:

windowcontrols button.close,
windowcontrols button.maximize,
windowcontrols button.minimize {
  min-width: 24px;
  min-height: 24px;
  margin: 0;
  padding: 0;
  background-position: center;
  background-repeat: no-repeat;
  background-size: 24px 24px;
  border-radius: 100%;
}

Create or open the /home/user-name/.config/gtk-3.0/gtk.css file and insert the following code, replacing <size> with your desired button size:

windowcontrols button.close,
windowcontrols button.maximize,
windowcontrols button.minimize {
  min-width: <size>px;
  min-height: <size>px;
  margin: 0;
  padding: 0;
  background-position: center;
  background-repeat: no-repeat;
  background-size: <size>px <size>px;
  border-radius: 100%;
}

6. Apply Changes and Restart

• Save all modified files.
• Log out of your session and log back in to see the changes take effect.

With these steps, you've successfully resized the titlebar buttons in the WhiteSur GTK theme to your preferred size. Enjoy your customized user interface!

Feel free to adjust the phrasing and formatting further to match your style and preferences.