I prefer

export ZSH_THEME=""

after soure $ZSH/oh-my-zsh.sh

# Compact one-line prompt: host and path on the left, Git on the right.
PROMPT='%F{cyan}%m%f:%F{blue}%1~%f %# '
RPROMPT='%(?..%F{red}exit:%?%f )$(git_prompt_info)'
ZSH_THEME_GIT_PROMPT_PREFIX='%F{245}(%F{cyan}'
ZSH_THEME_GIT_PROMPT_SUFFIX='%F{245})%f'
ZSH_THEME_GIT_PROMPT_CLEAN=''
ZSH_THEME_GIT_PROMPT_DIRTY='%F{yellow}*%f'

as for PS1:

• git info not shown
• PS1 is one-line instead of two
• path (at lease basename)
• hostname is shown
• not too colorful (which would be distracting)
• (NOT MET) no red color (as it looks like Error of compilation message)