We at LampWave Studio have a big background in web development, and all of our collaborators have experience developing websites commercially.
The job you described sounds perfectly within our skill set, from the front-end to the back-end of this renewal on your login page to the Jquery animations you described we got you covered.
We have senior coders among our team who will be able to ensure the architecture of this project stands the test of time and provide you with highly documented & tested code.
This ensures that whoever in the future might look at the code we providing, will be at ease, changing/adapting it according your needs.
Please, feel free to ask for any information that might ease your decision and assure you we have the skill to fulfill your requests.