Having problems with using casper3 and CSS

When i bring in outside css files i put them in a folder called css under the static folder. my goal is to ONLY change the footer and navigation header of casper3. i want the body to stay the same. when i bring in my own css files the whole body portion of the page goes blank. Also my the css in the footer dosent work like its supposed. small things are off like position and font size. can anyone help me?

The Casper 3 theme has a dedicated issues queue. Please post your question there. Thanks.