Light syntax themes:
    GitHub
    Monokai Extended Light
    OneHalfLight
    Solarized (light)
    gruvbox-light

Dark syntax themes:
    1337
    Coldark-Cold
    Coldark-Dark
    DarkNeon
    Dracula
    Monokai Extended
    Monokai Extended Bright
    Monokai Extended Origin
    Nord
    OneHalfDark
    Solarized (dark)
    Sublime Snazzy
    TwoDark
    Visual Studio Dark+
    ansi
    base16
    base16-256
    gruvbox-dark
    zenburn

Use delta --show-syntax-themes to demo the themes.
The main way to use delta is to configure it as the pager for git: see https://github.com/dandavison/delta#get-started. You can also use delta to diff two files: `delta file_A file_B`.