Buttons
There are two button types: "Add to cart" button (the "Checkout" button in the cart page is the same) and any other button.
There are btn_addtocart.gif and btn.png images in the [YourMagentoDir] /skin / frontend / default / [health-and-beauty] / images / folder.
btn_cart.png = "Add to cart" button on the product page
btn.png = any other button
In order to change button text color open [YourMagentoDir] / skin / frontend / default / [health-and-beauty] / css / color.css and find the following code in the end of the file.
Feel free to make changes.
Backgrounds
In order to change the background, open /YourMagentoDir/skin/frontend/default/[health-and-beauty]/css/skin.css, and add the following code to the end of skin.css file.
In order to change the background of the certain category, get the CSS class of the body tag for this page category.
Open /YourMagentoDir/skin/frontend/default/YourSkin/css/skin.css, and add the following code to the end of skin.css file.