Sometimes reading official docs is the fastest way to get all the necessary and right information. But I've found that for me, the current documentation format isn't comfortable to read, even on 4k 27" IPS display. So, if somebody feels the same, I consider there are four simple steps to change the situation.

1. Move docs to an external browser(chromium-based in this article).
   
2. Change default page font in the browser to something more weight.
   
3. Increase the font size to amplify the effect.
   
4. Slightly adjust contrast to reduce the brightness of white background.
   

1) Set HOUDINI_EXTERNAL_HELP_BROWSER to 1.
Create a new text file in \houdini18.0\packages and call it ExtBrowser.json
And paste JSON code inside:

{
    "env" : 
    [
        {
            "HOUDINI_EXTERNAL_HELP_BROWSER" :
            {
                "value": "1",
                "method": "replace"
            }
        }
    ]
}

Restart Houdini.

There is also an old-fashion way to do the same thing. See https://houdinitricks.com/default-web-browser-houdini-docs/ [houdinitricks.com]
2) Install chromium extension: Font changer (found it in a web)
https://chrome.google.com/webstore/detail/font-changer-with-google/jgjhhoglgjdklldfgoffdiaceffijeke [chrome.google.com]
2.1) Change font to Montserrat, weight: Bold.
Montserrat is a font that is very popular for article titles. But when you read a paragraph text, it makes your brain read everything smoothly, not just skip half of the page.

3) To amplify the effect, use CTRL + Scroll and increase the page size (200% in my case)
4) Install chromium extension: Dark reader.
https://chrome.google.com/webstore/detail/dark-reader/eimadpbcbfnmbkopoojfekhnkhdbieeh [chrome.google.com]
4.1) In Dark reader's options change Filter mode to light
4.2) Reduce in contrast to -10;
4.3) Change theme generation mode to Filter+ in More tab.


(There is also an option for font changing, but I think Font changer extension is more configurable).

Attachments:
overall.png (598.4 KB)
fontChanger.png (83.1 KB)
darkreader_contrast.png (124.1 KB)
darkreader_theme.png (127.8 KB)
packages.png (46.1 KB)
ExtBrowser.json (190 バイト)

or edit some lines in css ))
font-size
background-color
color

+ maybe some paddings

$HFS/houdini/python2.7libs/houdinihelp/static/scss/hpage.css
C:\Program Files\Side Effects Software\Houdini XX.X.XXX\houdini\python2.7libs\houdinihelp\static\scss\hpage.css

Attachments:
sshot_816.jpg (240.0 KB)

code {
    font-size: 15px;
    background-color: rgba(100, 100, 190, 0.2);
    padding: 0.1em;
}

Attachments:
Screenshot 2024-05-15 091948.png (507.8 KB)
Screenshot 2024-05-15 092125.png (34.0 KB)