To create a custom style using the colors from your website, you'll need a program that can tell you the hex code of those colors. Then you'll use those hex codes to change the colors in your own, custom style. Whether you're a Mac, or PC user, there are free options, and also software you can buy for added security and functionality.
For Mac Users
There is a built-in feature you can use, called the Digital Color Meter.
- In Finder, open your Applications folder.
 - Scroll to the Utilities folder, and open it.
 - Open Digital Color Meter.
 - Set the menu to Display in Generic RGB.
 - Click the View menu.
 - Select Display Values, and as Hexidecimal.
 - Open your site in a browser, and switch back to Digital Color Meter.
 - Hover the mouse over the color on your site.
 - Enter shift+command+c to copy the color as a hex code, and paste it somewhere to remember it.
 - Save all the colors you want to use, and then proceed with the next step.
 
For PC Users
Color Picker Suggestions:
Anny Studio's Just Color Picker
Iconico's ColorPic
WinCatalog's GetColor!
Instructions for Anny Studio's Just Color Picker:
- Go to the download page, and click Download free Just Color Picker 4.6 for Windows (EXE, 32 & 64 bit, portable).
 - Open and run the application.
 - Click the HTML menu, and select HEX.
 - Open your site in a browser, and switch back to Just Color Picker.
 - Hover your mouse over the color you want.
 - Enter alt+x to copy that color in the list on the right.
 - The hex code is the 6 characters after the Ox. Save this value somewhere to remember it.
 - Save all the colors you want to use, and then proceed with the next step.
 
Next step
More info