There are a gazillion websites out there. Every now and then you find one that has some features you like. Firefox and Chrome (and probably other browsers too) offer some tools to let you examine how the websites are put together. The first tool is the Page Source Tool. You will find it under the View menu in older versions of Firefox as shown below:
In newer versions of FF, you will find it under Tools-->Web Development as follows:
In Chrome, you will find this tool under the "wrench" icon as follows:
When selected, another window will open with the source HTML code for the webpage you are viewing. In this code window, you can view, select, copy the code for the webpage.
What you may find are links (url's) to other resources like .css files and .js files. If you are interested in these files - simple load the links. Then you can examine the structure of those files as well.