HL is skinable. The buttons, window, text, background, and sounds can all be colored or changed with most paint programs and any .wav files you want. All it takes is a little creativity.
In the HL\SKINS folder, make a copy of the default folder for something to start with. As long as there are appropriately sized objects with the name HL expects to see, you can color them anything you wish. The same goes for sounds. To change colors of text and text boxes edit the skin.cfg file in your new folder. When you are satisfied with your creation and it's new sounds, edit the skin.cfg file in your folder to reflect your name, logo, copyright, etc. With the HL window active, select "Skin Manager" and click "refresh", from there you can select your skin.
If you have custom HL skins to share, e-mail me and I'll link to them or post them on this site.
