Pretty clever to pre-define a bunch of attractive themes so developers don't have to think too hard (or do too much of what they're often not good at - UI design). Check out the R.style page and look at everything that begins with "Theme_". They basically act like CSS. I'm playing around with the Dialog theme for an "About Us" popup. You utilize it while defining the activity in AndroidManifest.xml: android:theme="@android:style/Theme.Dialog"