CSS Dropdown Menu for existing HTML5 website

Hello, Easy project today. I need a CSS drop-down menu added to current HTML5 and CSS3 website file. I would like the addition to be made in the CSS style sheet so that I can implement drop-down menus in the nav bar across the website. After CSS is completed please implement an example on the "[login to view URL]" page I will then implement it across the rest of the site The drop-down menu should be in visual sync with the site Nav bar (white/grey and then green when an object is rolled over). I have attached the site files to this project. You can also preview a live demo of this site here - [login to view URL] I would like the main menu to be able to have multiple drop down menu navigation. As an example look below for what I am referencing - Home Services Engineering Structural Engineering etc etc Safety Consulting Training Expert Witness Events/Presentations About Contact This should be a quick and easy project for anyone who knows what they are doing. Payments are prompt. Further instruction will gladly be provided if needed. Thanks!