The Music Player is slightly modified by me to my liking. Code written by Divya from this Medium guide and also in this GitHub repository.
The Colored Buttons all come from W3School's CSS Buttons. From changing when hovering over it, rounded corners, to the different colors all came from this website.
As well as the Employees Only Collapsible section comes from W3School's Collapsible. This is also modified to my liking by a lot I'll say.