You are probably missing the Theme CSS file. Dijit is themed entirely in CSS using unique class names located in the templates themselves.
To use a Dijit theme, you must import the themename.css file. The Dijit default theme is Tundra,
and the CSS lives in toolkit_root/dijit/themes/tundra/tundra.css. Import that file using a LINK tag or style tag with an @import call:
@import "js/dijit/themes/tundra/tundra.css";
