I'm creating a site that needs to be managed by a client through WordPress' backend. I think the interface may be too complicated for my client. I want to create my own interface from scratch and 'insert' some WordPress function into my custom design. I also don't want to explicitly modify the stock admin page so I can make changes there if needs be.
Unfortunately I can't seem to find anything online to help me with this process other than plugins that don't satisfy my needs. I've been searching for a few days now to no avail.
I want my client to sign in on a custom designed login page and use a custom designed CMS.
Any idea how to go about this?