how could change tab symbol color a little darker, it's so obvous now

[iysheng]

I like this colorscheme ,it's amazing, but when i see the kernel code, i found a place of maladjustment, first i set tab symbol as >--- to make a difference this space symbol;
when i see the code, I get the effect as below:

need help , how could i let the >--- symbol darker make the eye more comfortable.