having trouble changing theme with old information

Help. I am trying to change themes from delectio to probama unfortunately everytime I do, my blog turns into just html no css and is no where near what the probama blog looks like. I have all my css in the theme file folder. What I can’t figure out is why it is working perfectly fine through mamp where I set up all my css and then when I bring it over to my WP account poop hits the fan.