The original graphics for Quake 3 Arena were designed for a time far in the past when games ran at 640x480 or 800x600 screen resolutions. Back then, the default graphics were suitable but on today's high resolutions screens the original menu graphics are soft-edged, pixelated or just seem dated.
Thanks to the hard work in the [HQQ] High Quality Quake mod, this issue can be quickly resolved. The menu system, game HUD, 2D icons and more have been corrected for current screen resolutions.
As this mod is often updated, be sure to grab the latest version.
And while you are updating your menu graphics be sure to check out ZTM's Flexible HUD which will correct an aspect ratio issue. These two mods complement each other nicely.
Review by Tig