I know it\'s possible with jquery to make something that looks like a select box so I can make it look however I want. However, with just css, how much control do I have?
You have some control, but there is quite a bit of variation between browsers and operating systems. For example, Internet Explorer on Windows will always show the standard grey down arrow, even though you can re-colour this in other browsers.
As for the part that drops down - these are option tags, not select; so to change them you'll be applying styles to the option tag instead:
select {
border: 1px solid red;
}
option {
background-color: blue;
}
Luckily some other people have done some research detailing what works and what doesn't, so here are some resources for you: