The Trunk Notes manual gives a partial example of using Lua to automatically switch your wiki to a night mode. The idea is that at night your wiki will use light text on a dark background to make reading easier. This blog post is going to give a more complete description of how to achieve this.

To start with you need to create a special stylesheet to use at night. Anything defined here will be added to the default stylesheet.

Create a new page in Trunk Notes called Night.css with the following text:

body {
  background-color: black;
  color: white;
}

The next step is to create the Lua script. Add a new page called DayNight.lua:

hour = tonumber(os.date('%H'))
if hour > 20 or hour < 7 then
    return "{{stylesheet Night.css}}"
end

Finally we need to ensure the script is run on each page load. Use the search in Trunk Notes to find the page Special:Header and add:

{{lua DayNight.lua}}

We’re done! You’ll now find that between 8pm and 7am that Trunk Notes uses white text on a black background.