/*
This style was made to address issues not present in other rounded tab styles:
Integration with New Tab Button Position
Forward-compatible with Firefox 3.1's new tab button
rounding of the other tab buttons you may not use anyway.
Utilization of "text-shadow" CSS selector to make the font "Glow"
Tabs should be on top for default configuration to work. But if your tab bar is still on the bottom, switch around the values for -moz-border-radius in the first code block.

I would like to thank everyone at userstyles.org who makes these awesome styles.

Additional notes:
I use a dark background, which explains the white-colored font. Change this to your liking.
I'm always one for the neon look, and text-shadow with 75% opaque font seems to do the trick. If you do change the colors, know the RGB of the color you want, keep the RGBA specification for text color and use an RGB spec for shadow.
Tab hover and tab active preferences can be added by the user. Look below.
If you're going for a lighted effect, use an "Off" (darker or gray) colored font for all tabs with no shadow and no transparency for best effect. Current settings gives the effect of inactive tabs being out of focus, while hover and active makes the text come more into focus.
If you don't know anything about text-shadow, or any of this stuff... what are you doing using Stylish? In any case, Google and forum.userstyles.org are your friends. Look up what you don't understand and educate yourself on what you can do with Stylish and some CSS.

VERY IMPORTANT NOTE: If you haven't already, remove/modify the tab focus rings. Details at http://forum.userstyles.org/comments.php?DiscussionID=2635
*/

@namespace url(http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul);

.tabbrowser-tab,
.tabs-newtab-button,
#tabs-newtab-button-start,
#tabs-newtab-button-end,
#tabs-newtab-button-left,
.tabs-alltabs-button,
.scrollbutton-up,
.scrollbutton-down
{
-moz-appearance: none !important;
background-color: transparent !important;
color: transparent !important;
text-shadow: white 0px 0px 1px !important;
font-weight: bold !important;
-moz-border-radius: 12px 12px 0px 0px !important;
}
/*-Below are tab hover and tab active properties.-*/

.tabbrowser-tab:not([selected="true"]):hover
{
color: rgba(255,255,255,0.38) !important;
font-weight: bold !important;
text-shadow: white 0px 0px 3px !important;
}

.tabbrowser-tabs [selected="true"]
{
color: rgba(255,255,255,0.76) !important;
text-shadow: white 0px 0px 3px !important;
}

/*
If there are other tab IDs or classes I forgot, be sure to look through DOM inspector, maybe even having to open a JAR or two and figure out what they are.

THEN, when you figure them out, be sure to send the text string I need to add to bluufoxx at gmail dot com.

Just the ID or class name I need will do, though the entire string would be preferable. Also, don't be afraid to tweak this up yourself!
*/