Applying the GitHub Dark Theme to Miniflux with GPT

By @Charlie Revett on @May 6, 2023

I use the GitHub dark theme for both my VS Code and terminal setup, and wanted to experiment with applying the theme to my self-hosted Miniflux app as I find the default colour scheme quite dull and poor for readability; plus consistency is key of course.

Miniflux offers a primitive CSS override via the settings page, so the goals for this experiment were:

Find the GitHub dark theme colour palette
Find the Miniflux theme CSS custom properties
Craft an OpenAI GPT prompt using the v3.5-turbo and apply it
Write no actual CSS

ℹ️

Miniflux is a “minimalist and opinionated feed reader” mainly used for RSS that you can self-host.

Screenshots

Before

After

Generating

Finding a full colour palette for the theme was tricky, however I found the best to be from the vv9k/vim-github-dark repo (see ghdark.vim). This gave us 10 colours for inspiration:

base0:      #0d1117
base1:      #161b22
base2:      #21262d
base3:      #89929b
base4:      #c6cdd5
base5:      #ecf2f8
red:        #fa7970
orange:     #faa356
green:      #7ce38b
lightblue:  #a2d2fb
blue:       #77bdfb
purple:     #cea5fb

The Miniflux theme CSS custom properties can be found within the :root block of system.css. I removed any lines which were not related to colour (to reduce prompt size), and replaced any existing hex values with #blank, as GPT would only change around 10-20% of the theme if existing values were present. This gives us:

:root {
  --body-color: #blank;
  --body-background: #blank;
  --hr-border-color: #blank;
  /* ... */
}

When crafting the final prompts, I needed to:

Split it in two as the CSS code block hit the character limit for v3.5-turbo
Instruct GPT to not include any explanation as it was explaining why each colour was used
Adjust the theme for links as GPT was using blue for nearly all text values

Using this colour palette (GitHub dark theme) as inspiration:

```
base0:      #0d1117
base1:      #161b22
base2:      #21262d
base3:      #89929b
base4:      #c6cdd5
base5:      #ecf2f8
red:        #fa7970
orange:     #faa356
green:      #7ce38b
light blue: #a2d2fb
blue:       #77bdfb
purple:     #cea5fb
```

Amend these CSS values (`#blank`) to create a new theme:

```css
:root {
  --body-color: #blank;
  --body-background: #blank;
  --hr-border-color: #blank;
  /* ... */
}
```

- Do not use blue for links, use `base5` instead
- Do not include any explanation, just the code block

Followed by:

Apply the same change to these CSS values (`#blank`) following the 
same theme as before:

```css
:root {
  --page-header-title-border-color: #blank;
  --logo-color: #blank;
  --logo-hover-color-span: #blank;
  /* ... */
}
```

Thoughts

I was impressed by GPT’s ability to generate only using the names of the CSS custom properties, without any existing colour values. I found the limitations of v3.5-turbo the most interesting part:

Being unable to return only the diff of the CSS code block
Wanting to explain why all the changes were made
Being overly zealous with the colour blue

Overall, applying the theme was a success; I was able to generate a custom theme without writing any CSS. If you're looking to customize your Miniflux theme, I highly recommend giving this method a try.