First is editing flash with style.swf, panal.swf. This way require flash technique, I’m not able to show you. So I show you second way – editing font.css.
As it said that editing flash is higher priority, you should remove or comment out these things in Tomcat X.X\webapps\src-9.40\secure\configuration\manifest.xml:
Next step is to open Tomcat X.X\webapps\src-9.40\secure\configuration\default\font.css, this is where you can modify the “Service Portal” color:
You can see color:#ffffff, #ffffff is white color in hex, you can check for color hex code here http://www.color-hex.com/.
After editing, you should clear SRC, tomcat cache.