Need to make my navbar responsive

Hay! We have an creative agency here in vienna, and need very often professional coders. NOT THESE GUYS THAT SAY "I WILL MAKE PERFEKT" and then they code something hole different to them what i need. I have an page now calles [login to view URL] I want recode that page to an static html5 & css page. My reasons are better speed performance, less requests, and cleaner code. I started self working on this, you can see how far i am at www.air-transfer.at. Now i need help to make my self coded navigation responsive. PLEASE READ CAREFULLY: 1. i dont want jquery 2. i dont want bootstrap 3. i dont want adding any other request to my page What i want is: An mobile navigation exact the same looking like [login to view URL] but simple clean coded solution with maybe an little script in html, and an simple clean short code in css, thats all. no jquerys, no bootstrap, no other junk code. for the icon bar i created my costom font where the bars will show up when typing "\" to the html code. If you finish this little project like i want, we can work in future project also together where i need whole pages, and other codings from you. In this case we will pay good money.