tmux-detect-theme

#!/bin/sh

current_mode=`gsettings get org.gnome.desktop.interface color-scheme`

set_light()
{
    tmux set -g status-style "fg=#6D8086 bg=#F6F5F4"
    tmux set -g window-status-current-style "fg=#504E55"
}

set_dark()
{
    tmux set -g status-style "fg=#999999 bg=#303030"
    tmux set -g window-status-current-style "fg=#E9E9EA"
}

toggle()
{
    case $current_mode in
        "'default'")
            set_light
            ;;
        "'prefer-dark'")
            set_dark
            ;;
    esac
}

toggle

gsettings monitor org.gnome.desktop.interface color-scheme |
    while read -r line; do
        current_mode="${line/* }"
        toggle
    done