I'm a bit of an emacs noob.
I'm completely satisfied with tomorrow-night-bright-theme
except the fluorescent one below
I'v read some articles explaining how to change font faces in Emacs.
1. Changing highlight line color in emacs
2. Change Emacs syntax highlighting colors
However, I don't know what symbol is related to that color.
Try M-x list-faces-display
RET. This will bring up a list of all defined faces, I guess you could easily spot the fluorescent one there.