UI refinement for TeenyURL

Refine the UI of LetsHire, the detailed information is listed as below:

1. Change the color of whole page background to  #F5F5F5, and page content to have a white background and rounded corners, let it be the same with LetsHire; 
2. Change font, margin, padding smaller;
3. Add fade out and fade in effect to the result shorten url when users click 'shorten' button in order to highlight it;
4. Remove the container for the original url input tag, and make it more clean and simple;
5. Many detailed changes.