Will using a CMS create restrictions on what I can and can't do in development? I've read a bunch of information on Squarespace, and they make it sound as though it's easy for developers to customize using style sheets, scripts, etc., but I'm a little skeptical. Also, will customizing code directly interfere with my client's ability to edit content through the CMS' UI? He isn't set on using a CMS at this point and I'm trying to decide whether or not to try to talk him out of it. Any info would be much appreciated. Thanks.