Tmux doesn't use gnome-terminal color palette
Version
Tmux - 3.1b
gnome-terminal - 2.31.3
.zshrc
202 #export TERM=xterm-256color
203 #export TERM=gnome-256color
204 export TERM=screen-256color
205 #export TERM=screen-256color-bce
.tmux.conf
248 # Enable RGB colour if running in xterm(1)
249 #set-option -ga terminal-overrides ",gnome*:tc"
250 #set-option -g default-terminal "gnome-256color"
251 #set-option -sa terminal-overrides ",xterm*:Tc"
252 #set-option -g default-terminal "xterm-256color"
253 set-option -g default-terminal "screen-256color"
254 set-option -ga terminal-overrides ",screen*:Tc"
in gnome-terminal text color ( without tmux )
in tmux text color ( in same gnome-terminal )
i used tmux -2 -u options but its color is little distortion this blue color look so dark so i can read text very well