Firefox/IE not displaying CSS with Drupal website In Firefox and IE (and maybe others?) it seems that the blocks that are built by drupal aren't having CSS applied to them. 

Any help at all would be wonderful, as the issue I'm having is not knowing where the issue lies. The site is http://confluencenter.arizona.edu/.

p.s.
I am very new to CSS and Drupal
It's more like a CSS issue. Your CSS has to be more organize and standard cross browsers. Try not to use "!important", because you don't want to over-use it as you will end up causing headaches down when maintaining the site.

Here are some example you can fix. 
Under file "blocks.css" line 303. 

.pane-block-4, .pane-block-5, .pane-upcoming-events, .pane-block-6 {
  width: 31.25% !important;
  min-height: 500px;
  float: left;
  overflow: hidden;
  position: relative;
}


Since there are 3 classes on each "div"(panel-pane pane-block pane-block-4), you should use something like this instead

#mini-panel-front_blocks .panel-pan {
  width: 31.25%;
  min-height: 500px;
  float: left;
  overflow: hidden;
  position: relative;
}


Hope this help